JP2020025238A - Control method and device for maximizing speaker system capacity - Google Patents

Abstract

To solve a problem in which, in a loudspeaker system that is becoming smaller, higher in performance, and lighter in weight, parameters related to respective evaluation items have a conflicting relationship in view of the performance of a system under the condition in which the cost, and the size and shape are minimum, and it is necessary to increase the degree of freedom in selecting all parameters, but it is not easy today, in which the degree of perfection is already high, and there are further needs in the market, and a definitive method of significantly expanding the degree of freedom in design is desired in order to satisfy these needs.SOLUTION: In particular, in bass and treble ranges, and generally in the entire band, regarding the various limiting capabilities of a sound reproduction system including a speaker system, the output voltage of a power amplifier, the supply voltage to a voice coil, the power consumption of the voice coil, the temperature of the voice coil, and the vibration amplitude of the voice coil are calculated from the set of known parameters and input signal required for calculation, and therefore, the operating condition is grasped, and the reproduction signal is suppressed to a state within an allowable limit.SELECTED DRAWING: Figure 5

Description

Speaker system impedance and admittance characteristics Power conversion efficiency of speaker system Low output impedance driving method and high output impedance driving method of speaker system Fast Fourier transform and inverse transform Impulse response Convolution or convolution integral voice coil Motion speaker power consumption voice coil Temperature Digital Sound Signal Processing

Throughout the description, the terms used in the claims are used.
Background art No. 1, Speaker system
FIG. 1 shows an example of characteristics of a speaker system prototyped for verification of the present invention described in claim 1.
The speaker system for the test is a speaker unit with a nominal diameter of 70 mm, a rated power of 15 W, an impedance of 8 ohms, and two resonators with an inner volume of 62.5 cm ^ 3, a diaphragm window area of 25 cm ^ 2, a weight of 40 g,
But,
The enclosed cabinet is 130mm in width, 94mm in height and 69mm in depth.
In FIG. 1, Impedance is the impedance characteristic of the speaker system under test.
The resonance characteristic of the gradual impedance increase band centered around 120 Hz is gradual. This is due to the fact that the sharp peak near 200Hz, usually called f0, when there is no resonator, couples with the resonance characteristics of the resonator and moves to the lower frequency side.
This characteristic is important in the design process for producing good bass reproduction characteristics.

Methods for designing such a speaker system are known and are described in the following patent documents. Although the expressions are different, the essence of the vibration mechanism is similar.
Japanese Patent Application No. 2010-251188 Loudspeaker device Japanese Patent Application No. 2011-514324 Loudspeaker device JP2010-097146 Sound absorbing structure group and acoustic room JP2010-097145 Sound absorbing structure group and acoustic room JP2010-031582 Sound absorbing structure group and acoustic room JP2007 The speaker system and speaker enclosure design method described above relates to improving bass reproduction performance.

Background technology No.2 Power amplifier
Generally, a power amplifier for sound reproduction is of a voltage output type. This is due to the fact that the characteristics of the speaker are implicitly defined as reproduction characteristics with a constant voltage input.
In addition, it has a strong peculiar tone near the bass resonance point called f0. The voltage output type power amplifier suppresses this inherent timbre more than the current output type. The suppression of resonance-point free vibration is evaluated by a parameter called a damping factor.
In the case of the impedance characteristics shown in the graph of FIG. 1, in a frequency band around 120 Hz where the impedance is high, the sound pressure of the current output power amplifier is about 10 dB stronger than that of the voltage output power amplifier. This is equivalent to three times the power difference.
The above is known.
SPL by Voltage Amplifier shows the sound pressure characteristics of a voltage output power amplifier.
SPL by Current Amplifier shows the sound pressure characteristics of a current output power amplifier.
In both characteristics, the level of the input signal is matched so that the SPL matches near 400 Hz at which the impedance shows the minimum value.

In the high frequency range, the impedance characteristic of the speaker system generally increases in proportion to the frequency. In the design process of the speaker unit, it is necessary to satisfy both the bass reproduction characteristics and the treble reproduction characteristics required by the supplier. There is always a cut-and-try task for both factors that have a trade-off relationship. In recent years, as of 2018, in particular, there has been a strong demand for higher performance of small speaker systems, and various attempts have been made to improve the performance of difficult bass reproduction. However, since high-frequency sound reproduction cannot be sacrificed, there is a demand for a method of greatly expanding the degree of freedom in design with a simpler technique.
Using a current output power amplifier greatly expands the degree of freedom in design and greatly improves the trade-off between low-frequency sound reproduction performance and high-frequency sound reproduction performance.

The high-frequency characteristic in FIG. 1 shows the fact. The output sound pressure from 3 kHz to 10 kHz is different from that of the voltage output power amplifier in the case of the current output power amplifier because of the impedance characteristic.
There is a significant improvement in proportion in the + 2dB range.
However, when a current output power amplifier is used, there are the following three problems.
First, the upper limit of the maximum output voltage is determined by the limitation by the power supply voltage of the power amplifier.
However, increasing the power supply voltage of the power amplifier extremely increases the probability of excessive input in a band where the impedance of the voice coil is small. Therefore, when the power supply voltage is increased, the rated output operation in all bands cannot be guaranteed.
Second, current output power amplifiers are not employed due to the problem of damping factors.
Third, as of 2018, 100% of power amplifiers for mass-produced products requiring low power consumption, space saving and low cost are switching-type voltage output power amplifiers. It is not easy to change the status quo of production sites that already have a high degree of perfection and a stable track record.

FIG. 2 shows the difference between the voltage output power amplifier and the current output power amplifier having the vibration amplitude of the voice coil. The frequency range of the displacement measuring instrument used to measure this characteristic is from 20 Hz to 500 Hz.
FIG. 2 shows that the speaker system has a significantly different vibration amplitude in the low frequency range between the current output power amplifier and the voltage output power amplifier. These characteristics, including FIG. 1, show that the current output power amplifier is more excellent in both low sound reproduction characteristics and high sound characteristics than the voltage output power amplifier.
However, since the vibration amplitude increases as the reproduction frequency shifts toward a lower frequency range, there is a limit to softening the damper and the edge in a small speaker system having a narrow dynamic range. This limit is the plateau in the ultra-low sound range of the vibration amplitude in FIG. 2 by increasing the elasticity of the damper according to the conventional design method. If the vibration amplitude of the voice coil can be known, the dynamic range of the low frequency range can be controlled on the signal processing side according to the low sound intensity of the signal, so that the elasticity of the damper can be softened.
The above is known.

Background art 3, voice coil temperature.
The allowable rated power of the speaker system is determined by the guaranteed maximum environmental temperature and the allowable temperature rise of the voice coil. This depends on the power loss of the voice coil, the heat capacity of the coil and the bobbin, and the heat radiation condition of the bobbin. Further, since the heat radiation condition of the voice coil generally depends on the vibration amplitude of the voice coil, the heat radiation condition is different between the low frequency range and the high frequency range. When the signal is only in the high frequency range, the vibration amplitude of the voice coil becomes extremely small, and as a result, the cooling effect by the airflow near the voice coil is extremely reduced. This must be taken into account depending on the purpose and type of speaker system and the conditions of use.
The above is known.

Background Art No. 4 Regarding signal processing
Acoustic signal processing of general consumer products incorporates functions of the minimum necessary size under limited DSP resources. However, the cost of materials necessary for improving both bass reproduction performance and treble reproduction performance is sufficiently higher than the cost of DSP resources. Therefore, the increase in cost required for signal processing required for additional DSP resources of about several tens of MPS does not become a large burden. In addition, as with the lineup of power amplifiers, there are many different types of DSPs on the market, so the only issue with signal processing is the choice.
In particular, it is difficult to estimate the risk of the design process for improving the performance of the speaker system beyond the current state.

Background technology 5,
A technique of approximating a given specific frequency characteristic with first-order and second-order filters is very generally used. In the case of a normal sound reproducing system, the phase characteristics are not important in practical use, so that it is possible to sufficiently approximate the phase characteristics by ignoring the phase characteristics and aiming at only the gain characteristics.
FIG. 4 shows the respective characteristics of the eight secondary filters necessary for this approximation and the overall characteristics of gain and phase. The adjustment of these filters focuses only on the gain characteristics and ignores the phase characteristics.

Background technology 6,
The actual measured value of the pure resistance of the voice coil of the speaker under test in FIGS. 1 and 2 is 6.84 ohms,
The absolute value of the impedance, which is the ratio of the actual value of the current value to the voltage value of a 440 Hz signal, is
6.6 ohms. The difference is 3.5%. That is, the impedance of the speaker system at the minimum point of impedance or the maximum point of admittance is approximately equal to the pure resistance of the voice coil. This proves that the measurement of the pure resistance of the voice coil can be obtained with necessary and sufficient accuracy from the measured values of the supply current and the supply voltage to the speaker system.

Background art 7,
For the test speaker shown in Figs. 1 and 2,
The measured value of the impedance of the voice coil at 440 Hz in an environment of room temperature 26 ° C is
6.6 ohms. In estimating the temperature rise, the temperature coefficient of resistance shall be 1.0035 / degree.
A current of 4000 Hz and 0.5 A was applied, and the measured value of the impedance of the voice coil at 440 Hz after 10 minutes was 8.4 ohms. From this, the temperature rise of the voice coil can be estimated to be 78 ° C.
A current of 80 Hz and 0.5 A was passed, and after 10 minutes, the measured value of the impedance of the voice coil at 440 Hz was 7.1 ohms. From this, the temperature rise of the voice coil can be estimated to be 22 ° C.
Since the heat loss of both voice coils can be considered to be the same for the same 0.5 A current, it can be concluded that the difference between the two is due to the difference in air flow heat radiation conditions caused by the voice coil vibration.
Since the temperature characteristic of the resistance of the voice coil used is known, the temperature or temperature rise of the voice coil can be measured by the method described in claim 2.

Patent literature is described in the background art.

In a speaker system that is becoming smaller, higher in performance and lighter in weight, it is necessary to comprehensively maximize important evaluation items in order to ensure reliability under conditions of desired cost and size.
For example,

Assignment 1
As a result of the miniaturization and the weight reduction, the bass reproduction ability generally decreases remarkably.

Assignment 2
Attempts to increase bass reproduction performance generally degrade treble reproduction performance.

In particular,
Assignment 3
The vibration amplitude of the voice coil in the impedance increase band increases, and the sound output in this band increases. When this frequency band is driven by an amplifier having a low impedance output, the current flowing through the speaker system decreases as the impedance increases. A power amplifier for driving a normal speaker has a low impedance output, and the power supplied to the speaker system in the band where the conversion efficiency is increased decreases in inverse proportion to the change in impedance.
That is, in this frequency band, the capability of the speaker system is not used up from the viewpoint of thermal design.

Assignment 4
Generally, the impedance of a speaker unit increases as the frequency increases in a high frequency range. The main cause is inductance caused by the voice coil. This is a main cause of a decrease in sound output in a high frequency band. This tendency becomes remarkable with the improvement of bass reproduction performance. The current consumption of the loudspeaker system under the maximum rated voltage corresponding to the nominal impedance at high frequencies is reduced.
As a result, the heat loss generated by the voice coil is reduced.
That is, in this frequency band, the capability of the speaker system is not used up from the viewpoint of thermal design.

Assignment 5
The maximum rated output of the power amplifier is designed to balance the maximum rated power of both in operation according to the nominal allowable power of the speaker system. That is, the nominal maximum effective voltage of the low output impedance power amplifier is designed based on the square root of the product of the nominal maximum rated power of the speaker and the nominal impedance. This is implemented without exception when designing a reproduction system in which the speaker system and the power amplifier are integrated.

Assignment 6
The power supply voltage for driving the power amplifier is determined based on a voltage that satisfies the maximum effective voltage.
It is customary to never design a power supply voltage that would damage or burn out the speaker system.

Assignment 7
From the aspect of allowable power, it is not general that the speaker system, the power amplifier, and the power supply circuit are designed beyond the necessary range and provided with an unnecessary margin.

Assignment 8
In general, under the conditions of minimum cost and minimum size and shape, the parameter groups corresponding to the respective evaluation items always have a conflicting relationship. It is imperative for a speaker system to increase the freedom of choice of all these conflicting parameters. However, it is extremely difficult to greatly expand the degree of freedom in design from today's state of perfection.

The present invention combines known techniques. In the given operating state of the sound reproducing device,
The present invention relates to a method for maximizing the capabilities of power amplifiers and speaker systems by estimating voltage, current, heat loss, temperature rise, and vibration amplitude by calculation and precisely controlling them so as not to exceed allowable limits.

Means 1,
Measure the resistance value Ra of the voice coil of the speaker system at the ambient temperature Qa.

Means 2,
Measure the impedance or admittance characteristics of the speaker system.

Means 3,
Based on the impedance or admittance characteristics of the speaker system,
Determines the output voltage of the voltage output power amplifier that can supply the maximum allowable current to the speaker system in all frequency bands. The allowable current is determined based on the allowable power of {1 + KRq * {qmax (t) -Qa}} * Ra * i (t) ^ 2. Krq is the temperature coefficient of resistance of the voice coil qmax (t) is the allowable temperature of the voice coil,
Ra is the pure resistance of the voice coil at the ambient temperature Qa.
Since the resistance value of the voice coil fluctuates depending on the temperature of the voice coil, the value is corrected depending on the calculated temperature of the voice coil. For example, in the description of the background art No. 7, when a DC current of 4000 Hz and 0.5 A flows, the resistance of the voice coil increases by 27% with respect to a normal temperature state.

Means 4,
Vmax, Imax, Pmax, Qmax, Dmax, Kvmin, Kvmax, Kvmin, Kimax, Kimin, Kpmax, Kpmin,
Determine KRq, Qa, Ra, Kqmax, Kqmin, Kdmax, Kdmin, Tva, Tvr, Tia, Tir, Tpa, Tpr, Tqa, Tqr.

Means 5,
G {f, q (t)} and the power amplifier and speaker system
Measure Y {f, q (t)}.

Means 6,
Determine the characteristics H (f) of the sound quality finishing filter to make the reproduction characteristics the expected characteristics.

Means 7,
A calculation function for calculating r (t), v (t), i (t), p (t), q (t), and d (t) is constructed.
r (t) = {1 + Krq * {q (t) -Qa}} is the calculated pure resistance of the voice coil
v (t) = e (t) * K (f) * G {f, q (t)} is the calculated voice coil voltage
i (t) = e (t) * K (f) * Y {f, q (t)} is the calculated voice coil current
p (t) = r (t) * {i (t)} ^ 2 is the calculated heat loss of the voice coil
q (t) = r (t) * {i (t) * J (f)} ^ 2 * Tq (f) is the calculated temperature rise of the voice coil
d (t) = e (t) * K (f) * D {f, q (t)} is the calculated vibration amplitude of the voice coil

Means 8,
A calculation function for calculating the strength suppression coefficients, Kv, Ki, Kp, Kq, and Kd has been built.
Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax｝ are voltage intensity suppression coefficients
Ki = Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax} is the current intensity suppression coefficient
Kp = Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax} is the heat loss strength loss suppression coefficient
Kq = Kq {q (t), Kqmin, Kqmax, Qmax} is the temperature intensity suppression coefficient
Kd = Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax) is the vibration amplitude intensity suppression coefficient

Means 9,
A calculation function for calculating the voice coil vibration amplitude suppression coefficient LCd {f, Kd} is built.

Means 10,
The calculation function to calculate the total suppression coefficient K (f) = Kv * Ki * Kp * Kq * LCd {f, Kd} is built.
Combine the above functions.

Effect 1,
The potential of the small speaker system can be maximized within the safe area.
Effect 2,
Although it is a calculated value in the aging test process, the voltage, current, power, temperature, and vibration amplitude status of the voice coil can be accurately monitored, thereby improving the objectivity of the reliability design.
Effect 3
If a problem such as failure or quality occurs during the sale of a product, it can be quickly responded by changing the set values of allowable limits of voltage, current, power, temperature, and vibration amplitude.
Effect 4
If a problem such as a change in the material or shape occurs during the production of a product, it can be quickly responded by changing the set values of the allowable limits of voltage, current, power, temperature, and vibration amplitude.

Difference in impedance characteristics of speaker system under test and reproduction characteristics between voltage output power amplifier and current output power amplifier Difference of impedance characteristics of speaker system under test and vibration amplitude frequency characteristics of voice coil by voltage output power amplifier and current output power amplifier Example of approximating given frequency characteristics with eight secondary filters Total gain characteristic and total phase characteristic by eight filters of frequency characteristic of Fig. 8 Block diagram for explaining claim 1 of the present invention Block diagram for explaining claim 2 of the present invention Block diagram for explaining a system in which a reproduction system is divided into bands.

First, various calculation functions are incorporated into the program of the acoustic signal processor.
2. Create a GUI that monitors the operation status of each part and has a function to rewrite parameters.
Part 3. Create a parameter design procedure manual Part 4. Create a device that can automatically measure key parameters that are a little cumbersome or have no measurement habit, and that can be connected to the target playback device by data communication.
5. Provide basic source programs for all programs to be incorporated into the processor.

1. Standardization of the design for obtaining the maximum effect of the reproduction device using the small speaker system. 2. Especially, the standardization of the design for obtaining the maximum effect of the reproduction device using the speaker system having the resonator. Shortening the product development process by making the design process of the playback device work part 4. Standardization of reliability design that enables the operator to grasp the operation status of the speaker unit. Part 5. The current temperature of the voice coil, although it is an estimated value by calculation. Can control.
Part 6. IP conversion of source code for a series of signal processing programs

FIG. 1 is an explanatory diagram showing the difference between the impedance characteristics of a speaker system of a test sample and the reproduction characteristics of a voltage output power amplifier and a current output power amplifier.
As described in the background art section.

FIG. 2 is an explanatory diagram of the difference between the impedance characteristics of the speaker system of the test sample and the vibration amplitude frequency characteristics of the voice coil between the voltage output power amplifier and the current output power amplifier.
As described in the background art section.

FIG. 3 is an explanatory diagram of an example in which a given frequency characteristic is approximated by eight secondary filters.
As described in the background art section.

FIG. 4 is an explanatory diagram of the overall gain characteristics and overall phase characteristics of the filter.
As described in the background art section.

FIG. 5 is a block diagram for explaining claim 1 of the present invention.
The details are as described in the claims, and the following is a supplementary explanation of the claims.
s (t) is a playback signal, Tone Conditioning is a sound quality finishing filter that adjusts the sound quality of the entire playback system, and Intensity Conditioning is a coefficient unit and low-frequency cutoff filter that comprehensively suppresses voltage, current, heat loss, temperature, and vibration amplitude. , Power Amp is a power amplifier,
Speaker System is the speaker system Seting Parameters are the parameters determined by design required for the function of the proposed system to function, and Signal Estimation is the instantaneous value of the voice coil's pure resistance, voltage, current, heat loss, temperature, vibration amplitude, etc. Intensity Detection is a function that calculates the control variables required to control the allowable limit of each factor based on the calculated values of voltage, current, heat loss, temperature, and vibration amplitude.
Formulas and parameters required for control are determined by design.

The function of suppressing the voltage of the voice coil or the output voltage of the power amplifier is controlled by Kv so that the amplitude of the voltage does not exceed the allowable value so that the output of the power amplifier does not saturate. The essence of the present invention is not voltage suppression inside the signal processing system but voltage suppression as a part of the operation state of the entire reproduction apparatus.

The voice coil current or power amplifier output current suppression function is controlled by Ki so that the current stays below the allowable value. The essence of the present invention is not the suppression of the amplitude inside the signal processing system, but the suppression of the current as a part of the operation state of the entire reproducing apparatus.

Kp is controlled so that the power consumption of the voice coil falls below the allowable value.
Kq is controlled so that the temperature or temperature rise of the voice coil stays below the allowable value.

Kd is controlled so that the vibration amplitude of the voice coil falls below the allowable value.
The suppression of the vibration amplitude of the voice coil does not control the magnitude of the signal, but causes the low-frequency cutoff filter to function and has a large effect on the lower frequency. Many songs have strong bass signals recorded. However, in normal listening at a signal level that is not so large, it is desirable to be able to reproduce to the maximum extent possible in the low frequency range. For this reason, it is effective to suppress the vibration amplitude by controlling the cutoff frequency of the bass cutoff filter LCd {f, Kd}.
There is no priority level for any of the suppression factors, and the factors that try to exceed
Suppression works by calculating K (f) = Kv * Ki * Kp * Kq * LCd {f, Kd}.
Vmax, Imax, Pmax, Qmax, and Dmax are determined in design based on the permissible limit values of the power amplifier and the speaker system, based on product planning and reliability design policies.
Kvmin, Kvmax, Kimin, Kimax, Kpmin, Kpmax, Kqmin, Kqmax are
It is designed and determined depending on Vmax, Imax, Pmax, Qmax, and Dmax.

Tva, Tvr, Tia, Tir, Tpa, Tpr, Tda, and Tdr are each determined by design according to the nature of the signal to be suppressed.
In general, the time constants of the fast attack time and the slow release time are appropriate for hearing.
The following values are guidelines as reference examples of attack time.
When Tva is less than about 10 msec, intermodulation distortion caused by saturation due to overvoltage is sensitive to hearing.
When Tia is less than about 100msec, short-time overcurrent is not sensitive to hearing.
When Tpa is less than about 1sec, the voice coil has heat capacity and short-time overpower is not a problem.
When Tda is about 10msec or less, the over-amplitude of the speaker system is sensitive to hearing as intermodulation distortion.
The standard for Tvr, Tir, Tpr, and Tdr is 1.5 to 30 seconds each.
It is necessary to minimize the uncomfortable feeling of the gain change, which is a by-product of the suppression function.
By assigning the time constants of the plurality of suppression functions to high speed and low speed, the uncomfortable feeling can be reduced. For example, voltage suppression is set to high speed, and current suppression is set to low speed. Furthermore, by applying two types of high speed and low speed to one suppression function, this uncomfortable feeling can be greatly reduced.

The detection of the temperature rise q (t) requires a calculation model that includes strictly complicated nonlinearities depending on the heat capacity and heat radiation conditions. However, in practice, a simple linear calculation model based on actual measurement values works well.
Jq (f) can model the square root of the intensity of the frequency characteristic of the temperature rise with a combination of first and second order filters.
Tq (f) is a characteristic under a heat radiation condition having a large thermal time constant. The temperature of the voice coil can be calculated by convolution integration with time-varying heat loss using the characteristic of the time lapse of the temperature rise as the integration nucleus of the impulse response characteristic.
The specific calculation formula is determined by design.
The calculation of the heat loss of the voice coil, which is the reference for temperature rise, uses a calculation model that takes into account the effect of the temperature rise of the voice coil's pure resistance. It can be calculated with sufficient accuracy.

Int {v (t)}, Int {i (t)}, Int {p (t)}, Int {d (t)} are voltage strength, current strength,
Heat loss intensity and vibration amplitude intensity.
The procedure for calculating each strength is determined by design.
Since it is necessary to detect the maximum instantaneous value,
Use the maximum absolute value of v (t), i (t), p (t), d (t).

FIG. 6 is an explanatory diagram of a measuring device having a function of obtaining main parameters of the setting parameters of FIG. 5 by automatic measurement and calculation.
In recent years, since most power amplifiers of small speaker systems have balanced outputs, the voltage detection portion is of a balanced type. An unbalanced type is acceptable as long as it can be measured without errors. rs is a current detection resistor having a small resistance value for current detection. By detecting the differential voltage across rs, the current supplied to the voice coil can be measured.
If the resistance of the voice coil is 4 ohms, the required value of rs can be 0.1 ohms for the required measurement.

DS measures the displacement of the voice coil.
For measuring the characteristics of the vibration amplitude, a white noise, an M-sequence random signal, or a signal that sweeps a sine wave is used.
Supply this signal to the power amplifier, or supply the measurement signal from the input terminal,
It can also be measured by setting H (f) and k (f) to 1 constantly.

G {f, q (t)} is a signal obtained by performing a fast Fourier transform of the voltage signal across the voice coil,
It can be obtained by dividing the measurement signal by the signal subjected to the fast Fourier transform.
Y {f, KRq, R, q (t)} is a signal obtained by subjecting the current signal of the voice coil to a fast Fourier transform,
It is obtained by dividing the measurement signal by the signal subjected to the fast Fourier transform.
In both G {f} and Y (f), the phase information is insignificant and can be ignored. Therefore, it is sufficient to calculate only the size. The calculation formulas reflecting the effect of the temperature rise q (t) of the voice coil of G {}, Y {} need not be a calculation formula expressed precisely and continuously.
By using the absolute value of the actual measurement value of G {f}, Y {f} at the temperature q (t) of a practically necessary and sufficient number of samples, sufficient accuracy is obtained by complementation between adjacent samples in practical use. Device can be realized.

R is the minimum value Fzmin of ABS {G (f, q (t)) / Y {f, q (t)}}.
There may be multiple minimum points Fzmin. In this case,
Select the minimum value of ABS {G (f, q (t)) / Y {f, q (t)}} at the minimum point.
The normal speaker Fzmin lies between 40Hz and 200Hz.

D {f, KRq, R, q (t)} is a signal obtained by performing a fast Fourier transform of the vibration amplitude of the voice coil,
It is obtained by dividing the test signal by the signal subjected to the fast Fourier transform.
The vibration amplitude of the voice coil is also affected by each component based on the temperature of the voice coil.
The calculation formula reflecting the effect of the temperature rise q (t) of the voice coil of D {} does not need to be a calculation formula accurately and continuously expressed.
By using the absolute value of the measured value of D {f, Kd} at a temperature q (t) of a practically necessary and sufficient number of samples, a device with practically sufficient accuracy can be realized.

Jq (f) is the frequency characteristic of the square root of the magnitude of the frequency characteristic of the temperature or the temperature rise value for each sampling frequency when a constant current is applied to the voice coil with the signal of the sampling frequency. The reason for the square root is that the power that causes the temperature rise of the voice coil in the subsequent calculation is r (t) * ｛i (t) * Jq (f)｝ ^ 2.
Because the temperature rise of the voice coil also depends on the vibration amplitude of the voice coil, the temperature rise also depends on the frequency of the voice coil current. In principle, Jp (f) is not a correction factor for the current, but this simplified calculation can provide sufficient accuracy for practical use.

Tq (f) is a time constant of temperature rise when a constant current is applied to the voice coil.
The temperature rise depends on the heat capacity and the heat radiation conditions, and is not necessarily a linear system, but is not necessarily linear. However, even if it is calculated as a linear concentrated constant system, no practically inconvenient error occurs.

FIG. 7 is a block diagram for explaining a system in which the reproduction system is divided into bands.
It is explanatory drawing corresponding to Claim 5.
An example is shown in which the band is divided by four types of speaker systems, and two types of speaker systems are connected to one system of power amplifier.
This system, for each band division system,
Has a common input signal s (t), a common sound quality finishing filter H (f), and a common overall suppression coefficient K (f) = K11 (f) * K12 (f) * K2 (f) * K3 (f) .
K11 is a suppression coefficient corresponding to the speaker system 11 of the system 11;
K11 = Kv11 * Ki11 * Kp11 * Kq11 * LCq11 {f, Kd11}.
Kv11 * Ki11 * Kp11 * Kq11 * LCd11 {f, Kd11} is Kv, Ki, Kp, Kq, LCd (f, Kd) described in claim 1.
Respectively correspond to the voltage, current, heat loss, temperature, and vibration amplitude suppression coefficient of the voice coil.
Kv11 * Ki11 * Kp11 * Kq11 * LCd11 {f, Kd11} is an output of Intensity-Detection-11, and corresponds to Intensity-Detection of Claim 1.
The Signal-Detection-11 calculates the pure resistance, voltage, current, heat loss, temperature, and vibration amplitude of the voice coil in accordance with the Intensity-Detection of the first aspect, and calculates the calculated values. Pass to 11.
The input signal of Signal-Detection-11 is s (t) * H (f) * K (f) as in claim 1.
The parameters determined by the design, which are required by the Intensity-Detection-11 and the Signal-Detection-11, are preliminarily incorporated into the system as in claim 1.

K12 is a suppression coefficient corresponding to the speaker system 12 of the system 12.
K2 is a suppression coefficient corresponding to the speaker system 2 of the system 2.
K3 is a suppression coefficient corresponding to the speaker system 3 of the system 3.
Intensity-Detection-12, Intensity-Detection-2, and Intensity-Detection-3 are suppression coefficients for each subband,
Signal-Detection-12, Signal-Detection-2, Signal-Detection-3 are detection signals in calculation of each divided band,
Parameter-Set-12, Parameter-Set-2, and Parameter-Set-3 are parameters required for signal detection calculation and strength calculation of each divided band.

It is a basic configuration of the present invention. All of them relate to a method of greatly increasing the degree of freedom in designing a small speaker system using a plurality of known techniques.
From the characteristics of the entire playback device, calculate the voltage, current, heat loss, temperature, and vibration amplitude of the voice coil by calculation, detect the state of each factor, and ensure that each factor does not exceed the allowable limit. Suppress the strength of each factor.
G {}, Y {}, D {} are each affected by the temperature of the voice coil. The actual measured value of the voice coil's pure resistance Ra in a specific temperature environment Qa is incorporated in the calculation process as a parameter required for the present invention in advance. When information on the environmental temperature of the voice coil is given from outside, the temperature of the voice coil obtained by the calculation according to the present invention can be calculated.

A second aspect of the present invention relates to a method and apparatus for automatic parameter generation that enables simple and accurate setting of complicated parameters described in the first aspect at a design site.
The temperature of the voice coil greatly changes according to the operating conditions, and as a result, the pure resistance of the voice coil greatly changes. The task of knowing the temperature of the voice coil is important for accurately understanding the operating state of the speaker system.
To calculate the temperature of the voice coil, it is necessary to know the relationship between the current of the environmental voice coil, the value of the pure resistance of the voice coil, and the thermal time constant. In addition, the influence on the heat radiation condition that depends on the vibration amplitude of the voice coil must be considered. Unless the product is equipped with a function of measuring the voltage and current of the operating voice coil, it is not possible to directly grasp the driving situation.
For the temperature rise described in claim 1, the temperature q (t) of the voice coil is estimated by a design formula determined using a parameter group actually measured in advance. Based on the estimated temperature of the voice coil, G {f}, Y {f}, D {f} and the temperature q (t) are also incorporated into the calculation formula and calculated.

Although the voltage and current of the voice coil with respect to the input of the power amplifier greatly depend on the pure resistance of the voice coil, the calculation model of G ({f} and Y {f} The change in resistance due to coil temperature must be reflected, the temperature of the voice coil required for these formulas is also a calculated value, and a series of results in which the calculated temperature value forms a closed loop. There is a concern that the calculation error due to the positive feedback or the negative feedback may further increase due to the calculation error of q (t) because it is included in the calculation of the ambient temperature. Since the function of measuring the temperature rise of the voice coil and the temperature of the voice coil is provided, it is possible to evaluate the error of the entire calculation processing based on claim 1. That is, the temperature estimated by the calculation. It is possible to verify whether there is a discrepancy between the voltage and current values of the voice coil calculated by the above and the measured voltage and current values.If the discrepancy is larger than expected, And the opportunity to review the formulas.
The values of G {f}, Y {f}, D {f} due to the rise in temperature of the voice coil are measured discretely using sample values of temperature, and the results obtained at all sample temperatures are sent to the playback device. hand over.

A third aspect of the present invention relates to a method of determining the specifications of the maximum output voltage of the power amplifier and the impedance of the speaker system in the case of the design of the conventional reproducing apparatus.
By maximizing the capability of the speaker system and operating it constantly within the safe area according to the method of claim 1, the output voltage of the power amplifier can be greatly increased without being bound by the conventional practice, or the speaker system The present invention relates to a technique capable of significantly reducing the impedance of a voice coil.

The supplementary explanation of claim 4 is based on the fact that a closed loop including itself is formed in the calculation process of r (t) and q (t) described in claim 1 through the calculation of i (t). It relates to the function of suppressing the expansion of calculation errors.

Supplementary explanation of claim 5 The present invention relates to an application of claim 1 in a case where a plurality of power amplifiers and speaker systems are provided and divided into bands. The filter for band division for each band is integrated with the power amplifier.
For each speaker system, parameter group and voice coil pure resistance, voltage, current,
It has a function of calculating signal detection and a function of calculating suppression coefficients for heat loss, temperature, and vibration amplitude. When multiple speaker systems are connected to a single power amplifier, the operating state is detected for each speaker system in a state where the power amplifier and each speaker system are combined, and the suppression coefficient is determined based on each allowable value. Is calculated.
The total suppression coefficient is a product of suppression coefficients calculated for each speaker system.
The inputs of all the power amplifiers are common, and the common signal is subjected to the sound quality finishing filter and the overall suppression coefficient of the entire reproduction system and supplied to the respective power amplifiers.
All operations in the case of band division are based on the operations described in claim 1.

Figure 1
Of the speaker system under test,
Impedance impedance characteristics
SPL by Voltage Amplifier SPL by voltage output power amplifier
SPL by Current Amplifier SPL by current output power amplifier

FIG.
Of the speaker system under test,
Voltage drive Displacement Vibration of voice coil by voltage drive
Current drive Displacement Vibration of voice coil by current drive

FIG.
Of the speaker system under test,
Admitance Admittance characteristics
By Secondary EQ Approximation by eight secondary filters

FIG.
The approximation characteristic of FIG.
EQ1, Eq2 ,,,,,,, EQ12 12 secondary filters
Gain Total gain characteristics of eight secondary filters
Pahse Total phase characteristics of eight second-order filters

FIG.
s (t) playback signal
Tone Conditioning sound quality finish
H (f) sound quality finishing filter
e (t) Output of sound quality finishing filter
K (f) = Kv * Ki * Kp * Kq * LCd (f, Kd) Total suppression coefficient
Power Amp Power amplifier
Speaker System Speaker System
SP speaker unit
Resonance resonator
e (t) * K (f) Power amplifier input
Ra Voice coil net resistance reference value (at ambient temperature Qa)
Qa ambient temperature
KRq Voice coil temperature coefficient of resistance
Minimal impedance of Fzmin voice coil
r (t) = {1 + KRq * q (t)} * R Voice coil resistance with corrected voice coil temperature
G {f, q (t)} Voltage frequency characteristics of voice coil to input of power amplifier
Y {f, q (t)} Current frequency characteristics of voice coil for power amplifier input
Jq (f) The temperature of the voice coil that depends on the signal frequency
Coefficient to be corrected by current conversion
Tq (f) Voice coil thermal time constant
D {f, q (t)} Vibration amplitude frequency characteristics of voice coil for power amplifier input
v (t) = e (t) * K (f) * G {f, q (t)} Calculated voice coil voltage
i (t) = e (t) * K (f) * Y {f, q (t)} Calculated voice coil current
p (t) = r (t) * {i (t)} ^ 2 Calculated heat loss of voice coil
q (t) = r (t) * {i (t) * J (f)} ^ 2 * Tp (f) Calculated voice coil temperature or temperature rise
d (t) = e (t) * K (f) * D {f, q (t)} Calculation of amplitude oscillation of voice coil
Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax｝ Voltage intensity suppression coefficient
Ki = Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax} Current intensity suppression coefficient
Kp = Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax} Heat loss strength loss suppression coefficient
Kq = Kq {q (t), Kqmin, Kqmax, Qmax} Temperature intensity suppression coefficient
Kd = Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax) Vibration amplitude intensity suppression coefficient
Tva, Tvr Attack time and release time for voltage strength measurement
Kvmin, Kvmax, Vmax Lower and upper limits of voltage intensity suppression coefficient, allowable voltage intensity
Tia, Tir Attack time and release time of current intensity measurement
Kimin, Kimax, Imax Lower and upper limits of current intensity suppression coefficient, allowable current intensity
Tpa, Tpr Attack time and release time for power intensity measurement
Kpmin, Kpmax, Pmax Lower and upper limits of power intensity suppression coefficient, allowable power intensity
Kqmin, Kqmax, Qmax Lower and upper limit of temperature intensity suppression coefficient, allowable temperature intensity
Tda, Tdr Attack time and release time of vibration amplitude intensity measurement
Kdmin, Kdmax, Dmax Lower and upper limits of vibration amplitude intensity suppression coefficient, allowable vibration amplitude intensity

FIG.
Measurement Equipment Parameter Measurement Tool
Displacement Sencer Voice coil vibration amplitude sensor
DS vibration amplitude sensor
Displacement Vibration amplitude measurement input
Test Signal Signal output for measurement
Voltage Voltage measurement input
Current Current measurement input
rs Current detection resistor
Dislacement Vibration amplitude measurement input
Measurment {G {f, q (t)}, Y {f, q (t)}, Ra, Qa, Jq (f), Tq (f), D {f, q (t)}}
Output of measured parameters

FIG.
K11 (f), K12 (f), K2 (f), K3 (f) Power amplifiers and speakers for each divided band
Suppression coefficient for each band corresponding to
K (f) = K11 (f) * K12 (f) * K2 (f) * K3 (f) Overall suppression coefficient
Power-Amp-1, Power-Amp-2, Power-Amp-3
Power amplifier with built-in split filter for each split band
H1 (f), H2 (f), H3 (f) Split characteristics for each split band
PA-1, PA-2, PA-3 Power amplifier for each divided band
Speaker-System-11 1st speaker system with split band 1
Speaker-System-12 Second speaker system with split band 1
Speaker-System-2 Split-band 2 speaker system
Speaker-System-3 Speaker system with 3 split bands
Parameter-set-1, Parameter-set-1, Parameter-set-1
Parameter group for each sub-band
Signal-Detection-1, Signal-Detection-2, Signal-Detection-3
Signal detection for each sub-band
Intensity-Detection-1, Intensity-Detection-2, Intensity-Detection-3
Intensity detection for each sub-band

Speaker system impedance and admittance characteristics Power conversion efficiency of speaker system Low output impedance driving method and high output impedance driving method of speaker system Fast Fourier transform and inverse transform Impulse response convolution or convolution integral voice coil Motion speaker power consumption voice coil Temperature Digital Sound Signal Processing

Throughout the description, the terms used in the claims are used.
Background art No. 1, Speaker system
FIG. 1 shows an example of characteristics of a speaker system prototyped for verification of the present invention described in claim 1.
The speaker system for the test is a speaker unit with a nominal diameter of 70 mm, a rated power of 15 W, an impedance of 8 ohms, and two resonators with an inner volume of 62.5 cm ^ 3, a diaphragm window area of 25 cm ^ 2, a weight of 40 g,
But,
The enclosed cabinet is 130mm in width, 94mm in height and 69mm in depth.
In FIG. 1, Impedance is the impedance characteristic of the speaker system under test.
The resonance characteristic of the gradual impedance increase band centered around 120 Hz is gradual. This is due to the fact that the sharp peak near 200Hz, usually called f0, when there is no resonator, couples with the resonance characteristics of the resonator and moves to the lower frequency side.
This characteristic is important in the design process for producing good bass reproduction characteristics.

Methods for designing such a speaker system are known and are described in the following patent documents. Although the expressions are different, the essence of the vibration mechanism is similar.
Japanese Patent Application No. 2010-251188 Loudspeaker device Japanese Patent Application No. 2011-514324 Loudspeaker device JP2010-097146 Sound absorbing structure group and acoustic room JP2010-097145 Sound absorbing structure group and acoustic room JP2010-031582 Sound absorbing structure group and acoustic room 2007 The speaker system and speaker enclosure design method described above relates to improving bass reproduction performance.

Background technology No.2 Power amplifier
Generally, a power amplifier for sound reproduction is of a voltage output type. This is due to the fact that the characteristics of the speaker are implicitly defined as reproduction characteristics with a constant voltage input.
In addition, it has a strong peculiar tone near the bass resonance point called f0. The voltage output type power amplifier suppresses this inherent timbre more than the current output type. The suppression of resonance-point free vibration is evaluated by a parameter called a damping factor.
In the case of the impedance characteristics shown in the graph of FIG. 1, in a frequency band around 120 Hz where the impedance is high, the sound pressure of the current output power amplifier is about 10 dB stronger than that of the voltage output power amplifier. This is equivalent to three times the power difference.
The above is known.
SPL by Voltage Amplifier shows the sound pressure characteristics of a voltage output power amplifier.
SPL by Current Amplifier shows the sound pressure characteristics of a current output power amplifier.
In both characteristics, the level of the input signal is matched so that the SPL matches near 400 Hz at which the impedance shows the minimum value.

In the high frequency range, the impedance characteristic of the speaker system generally increases in proportion to the frequency. In the design process of the speaker unit, it is necessary to satisfy both the bass reproduction characteristics and the treble reproduction characteristics required by the supplier. There is always a cut-and-try task for both factors that have a trade-off relationship. In recent years, as of 2018, in particular, there has been a strong demand for higher performance of small speaker systems, and various attempts have been made to improve the performance of difficult bass reproduction. However, since high-frequency sound reproduction cannot be sacrificed, there is a demand for a method of greatly expanding the degree of freedom in design with a simpler technique.
Using a current output power amplifier greatly expands the degree of freedom in design and greatly improves the trade-off between low-frequency sound reproduction performance and high-frequency sound reproduction performance.

The high-frequency characteristic in FIG. 1 shows the fact. The output sound pressure from 3 kHz to 10 kHz is different from that of the voltage output power amplifier in the case of the current output power amplifier because of the impedance characteristic.
There is a significant improvement in proportion in the + 2dB range.
However, when a current output power amplifier is used, there are the following three problems.
First, the upper limit of the maximum output voltage is determined by the limitation by the power supply voltage of the power amplifier.
However, increasing the power supply voltage of the power amplifier extremely increases the probability of excessive input in a band where the impedance of the voice coil is small. Therefore, when the power supply voltage is increased, the rated output operation in all bands cannot be guaranteed.
Second, current output power amplifiers are not employed due to the problem of damping factors.
Third, as of 2018, 100% of power amplifiers for mass-produced products requiring low power consumption, space saving and low cost are switching-type voltage output power amplifiers. It is not easy to change the status quo of production sites that already have a high degree of perfection and a stable track record.

FIG. 2 shows the difference between the voltage output power amplifier and the current output power amplifier having the vibration amplitude of the voice coil. The frequency range of the displacement measuring instrument used to measure this characteristic is from 20 Hz to 500 Hz.
FIG. 2 shows that the speaker system has a significantly different vibration amplitude in the low frequency range between the current output power amplifier and the voltage output power amplifier. These characteristics, including FIG. 1, show that the current output power amplifier is more excellent in both low sound reproduction characteristics and high sound characteristics than the voltage output power amplifier.
However, since the vibration amplitude increases as the reproduction frequency shifts toward a lower frequency range, there is a limit to softening the damper and the edge in a small speaker system having a narrow dynamic range. This limit is the plateau in the ultra-low sound range of the vibration amplitude in FIG. 2 by increasing the elasticity of the damper according to the conventional design method. If the vibration amplitude of the voice coil can be known, the dynamic range of the low frequency range can be controlled on the signal processing side according to the low sound intensity of the signal, so that the elasticity of the damper can be softened.
The above is known.

Background art 3, voice coil temperature.
The allowable rated power of the speaker system is determined by the guaranteed maximum environmental temperature and the allowable temperature of the voice coil. This depends on the power loss of the voice coil, the heat capacity of the coil and the bobbin, and the heat radiation condition of the bobbin. Further, since the heat radiation condition of the voice coil generally depends on the vibration amplitude of the voice coil, the heat radiation condition is different between the low frequency range and the high frequency range. When the signal is only in the high frequency range, the vibration amplitude of the voice coil becomes extremely small, and as a result, the cooling effect by the airflow near the voice coil is extremely reduced. This must be taken into account depending on the purpose and type of speaker system and the conditions of use.
The above is known.

Background Art No. 4 Regarding signal processing
Acoustic signal processing of general consumer products incorporates functions of the minimum necessary size under limited DSP resources. However, the cost of materials necessary for improving both bass reproduction performance and treble reproduction performance is sufficiently higher than the cost of DSP resources. Therefore, the increase in cost required for signal processing required for additional DSP resources of about several tens of MPS does not become a large burden. In addition, as with the lineup of power amplifiers, there are many different types of DSPs on the market, so the only issue with signal processing is the choice.
In particular, it is difficult to estimate the risk of the design process for improving the performance of the speaker system beyond the current state.

Background technology 5,
A technique of approximating a given specific frequency characteristic with first-order and second-order filters is very generally used. In the case of a normal sound reproducing system, the phase characteristics are not important in practical use, so that it is possible to sufficiently approximate the phase characteristics by ignoring the phase characteristics and aiming at only the gain characteristics.
FIG. 4 shows the respective characteristics of the eight secondary filters necessary for this approximation and the overall characteristics of gain and phase. The adjustment of these filters focuses only on the gain characteristics and ignores the phase characteristics.

Background technology 6,
The actual measured value of the pure resistance of the voice coil of the speaker under test in FIGS. 1 and 2 is 6.84 ohms,
The absolute value of the impedance, which is the ratio of the measured current value to the measured voltage value with a 440 Hz signal, is 6.6 ohms. The difference is 3.5%. That is, the impedance of the speaker system at the minimum point of impedance or the maximum point of admittance is approximately equal to the pure resistance of the voice coil. This proves that the measurement of the pure resistance of the voice coil can be obtained with necessary and sufficient accuracy from the measured values of the supply current and the supply voltage to the speaker system.

Background art 7,
For the test speaker shown in Figs. 1 and 2,
The actual measured value of the impedance of the voice coil at 440 Hz in an environment at room temperature of 26 degrees C is 6.6 ohms. In estimating the temperature rise, the temperature coefficient of resistance shall be 1.0035 / degree.
A current of 4000 Hz and 0.5 A was applied, and the measured value of the impedance of the voice coil at 440 Hz after 10 minutes was 8.4 ohms. From this, the temperature rise of the voice coil can be estimated to be 78 ° C.
A current of 80 Hz and 0.5 A was passed, and after 10 minutes, the measured value of the impedance of the voice coil at 440 Hz was 7.1 ohms. From this, the temperature rise of the voice coil can be estimated to be 22 ° C.
Since the heat loss of both voice coils can be considered to be the same for the same 0.5 A current, it can be concluded that the difference between the two is due to the difference in air flow heat radiation conditions caused by the voice coil vibration.
Since the temperature characteristics of the resistance of the voice coil used are known, the temperature rise and temperature of the voice coil can be measured by the method described in claim 2.

Patent literature is described in the background art.

In a speaker system that is becoming smaller, higher in performance and lighter in weight, it is necessary to comprehensively maximize important evaluation items in order to ensure reliability under conditions of desired cost and size.
For example,

Assignment 1
As a result of the miniaturization and the weight reduction, the bass reproduction ability generally decreases remarkably.

Assignment 2
Attempts to increase bass reproduction performance generally degrade treble reproduction performance.

In particular,
Assignment 3
The vibration amplitude of the voice coil in the impedance increase band increases, and the sound output in this band increases. When this frequency band is driven by an amplifier having a low impedance output, the current flowing through the speaker system decreases as the impedance increases. A power amplifier for driving a normal speaker has a low impedance output, and the power supplied to the speaker system in the band where the conversion efficiency is increased decreases in inverse proportion to the change in impedance.
That is, in this frequency band, the capability of the speaker system is not used up from the viewpoint of thermal design.

Assignment 4
Generally, the impedance of a speaker unit increases as the frequency increases in a high frequency range. The main cause is inductance caused by the voice coil. This is a main cause of a decrease in sound output in a high frequency band. This tendency becomes remarkable with the improvement of bass reproduction performance. The current consumption of the loudspeaker system under the maximum rated voltage corresponding to the nominal impedance at high frequencies is reduced.
As a result, the heat loss generated by the voice coil is reduced.
That is, in this frequency band, the capability of the speaker system is not used up from the viewpoint of thermal design.

Assignment 5
The maximum rated output of the power amplifier is designed to balance the maximum rated power of both in operation according to the nominal allowable power of the speaker system. That is, the nominal maximum effective voltage of the low output impedance power amplifier is designed based on the square root of the product of the nominal maximum rated power of the speaker and the nominal impedance. This is implemented without exception when designing a reproduction system in which the speaker system and the power amplifier are integrated.

Assignment 6
The power supply voltage for driving the power amplifier is determined based on a voltage that satisfies the maximum effective voltage.
It is customary to never design a power supply voltage that would damage or burn out the speaker system.

Assignment 7
From the aspect of allowable power, it is not general that the speaker system, the power amplifier, and the power supply circuit are designed beyond the necessary range and provided with an unnecessary margin.

Assignment 8
In general, under the conditions of minimum cost and minimum size and shape, the parameter groups corresponding to the respective evaluation items always have a conflicting relationship. It is imperative for a speaker system to increase the freedom of choice of all these conflicting parameters. However, it is extremely difficult to greatly expand the degree of freedom in design from today's state of perfection.

The present invention combines known techniques. Given the operating state of the sound reproducing device, the voltage, current, heat loss, temperature, and vibration amplitude of the voice coil are estimated by calculation and precisely controlled so as not to exceed the allowable limit, so that the power amplifier and speaker system have How to get the most out of it.

Means 1,
Measure the resistance value Ra of the voice coil of the speaker system at the ambient temperature Qa.

Means 2,
Measure the impedance or admittance characteristics of the speaker system.

Means 3,
Based on the impedance or admittance characteristics of the speaker system,
Determines the output voltage of the voltage output power amplifier that can supply the maximum allowable current to the speaker system in all frequency bands. The allowable current is determined based on the allowable power of {1 + KRq * {qmax (t) -Qa}} * Ra * i (t) ^ 2. Krq is the temperature coefficient of resistance of the voice coil qmax (t) is the allowable temperature of the voice coil,
Ra is the pure resistance of the voice coil at the ambient temperature Qa.
Since the resistance value of the voice coil fluctuates depending on the temperature of the voice coil, the value is corrected depending on the calculated temperature of the voice coil. For example, in the description of the background art No. 7, when a DC current of 4000 Hz and 0.5 A flows, the resistance of the voice coil increases by 27% with respect to a normal temperature state.

Means 4,
Vmax, Imax, Pmax, Qmax, Dmax, Kvmin, Kvmax, Kvmin, Kimax, Kimin, Kpmax, Kpmin,
Determine KRq, Qa, Ra, Kqmax, Kqmin, Kdmax, Kdmin, Tva, Tvr, Tia, Tir, Tpa, Tpr, Tqa, Tqr.

Means 5,
G {f, q (t)} and the power amplifier and speaker system
Measure Y {f, q (t)}.

Means 6,
Determine the characteristics H (f) of the sound quality finishing filter to make the reproduction characteristics the expected characteristics.

Means 7,
A calculation function for calculating r (t), v (t), i (t), p (t), q (t), and d (t) is constructed.
r (t) = {1 + Krq * {q (t) -Qa}} is the calculated pure resistance of the voice coil
v (t) = e (t) * K (f) * G {f, q (t)} is the calculated voice coil voltage
i (t) = e (t) * K (f) * Y {f, q (t)} is the calculated voice coil current
p (t) = r (t) * {i (t)} ^ 2 is the calculated heat loss of the voice coil
q (t) = Qe + r (t) * {i (t) * J (f)} ^ 2 * Tq (f) is the calculated temperature rise of the voice coil
d (t) = e (t) * K (f) * D {f, q (t)} is the calculated vibration amplitude of the voice coil

Means 8,
A calculation function for calculating the strength suppression coefficients, Kv, Ki, Kp, Kq, and Kd has been built.
Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax｝ are voltage intensity suppression coefficients
Ki = Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax} is the current intensity suppression coefficient
Kp = Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax} is the heat loss strength loss suppression coefficient
Kq = Kq {q (t), Kqmin, Kqmax, Qmax} is the temperature intensity suppression coefficient
Kd = Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax) is the vibration amplitude intensity suppression coefficient

Means 9,
A calculation function for calculating the voice coil vibration amplitude suppression coefficient LCd {f, Kd} is built.

Means 10,
The calculation function to calculate the total suppression coefficient K (f) = Kv * Ki * Kp * Kq * LCd {f, Kd} is built.
Combine the above functions.

Effect 1,
The potential of the small speaker system can be maximized within the safe area.
Effect 2,
Although it is a calculated value in the aging test process, the voltage, current, power, temperature, and vibration amplitude status of the voice coil can be accurately monitored, thereby improving the objectivity of the reliability design.
Effect 3
If a problem such as failure or quality occurs during the sale of a product, it can be quickly responded by changing the set values of allowable limits of voltage, current, power, temperature, and vibration amplitude.
Effect 4
If a problem such as a change in the material or shape occurs during the production of a product, it can be quickly responded by changing the set values of the allowable limits of voltage, current, power, temperature, and vibration amplitude.

Difference in impedance characteristics of speaker system under test and reproduction characteristics between voltage output power amplifier and current output power amplifier Difference of impedance characteristics of speaker system under test and vibration amplitude frequency characteristics of voice coil by voltage output power amplifier and current output power amplifier Example of approximating given frequency characteristics with eight secondary filters Total gain characteristic and total phase characteristic by eight filters of frequency characteristic of Fig. 8 Block diagram for explaining claim 1 of the present invention Block diagram for explaining claim 2 of the present invention Block diagram for explaining a system in which a reproduction system is divided into bands.

First, various calculation functions are incorporated into the program of the acoustic signal processor.
2. Create a GUI that monitors the operation status of each part and has a function to rewrite parameters.
Part 3. Create a parameter design procedure manual Part 4. Create a device that can automatically measure key parameters that are a little cumbersome or have no measurement habit, and that can be connected to the target playback device by data communication.
5. Provide basic source programs for all programs to be incorporated into the processor.

1. Standardization of the design for obtaining the maximum effect of the reproduction device using the small speaker system. 2. Especially, the standardization of the design for obtaining the maximum effect of the reproduction device using the speaker system having the resonator. Shortening the product development process by making the design process of the playback device work part 4. Standardization of reliability design that enables the operator to grasp the operation status of the speaker unit. Part 5. The current temperature of the voice coil, although it is an estimated value by calculation. Can control.
Part 6. IP conversion of source code for a series of signal processing programs

FIG. 1 is an explanatory diagram showing the difference between the impedance characteristics of a speaker system of a test sample and the reproduction characteristics of a voltage output power amplifier and a current output power amplifier.
As described in the background art section.

FIG. 2 is an explanatory diagram of the difference between the impedance characteristics of the speaker system of the test sample and the vibration amplitude frequency characteristics of the voice coil between the voltage output power amplifier and the current output power amplifier.
As described in the background art section.

FIG. 3 is an explanatory diagram of an example in which a given frequency characteristic is approximated by eight secondary filters.
As described in the background art section.

FIG. 4 is an explanatory diagram of the overall gain characteristics and overall phase characteristics of the filter.
As described in the background art section.

FIG. 5 is a block diagram for explaining claim 1 of the present invention.
The details are as described in the claims, and the following is a supplementary explanation of the claims.
s (t) is a playback signal, Tone Conditioning is a sound quality finishing filter that adjusts the sound quality of the entire playback system, and Intensity Conditioning is a coefficient unit and low-frequency cutoff filter that comprehensively suppresses voltage, current, heat loss, temperature, and vibration amplitude. , Power Amp is a power amplifier,
Speaker System is the speaker system Seting Parameters are the parameters determined by design required for the function of the proposed system to function, and Signal Estimation is the instantaneous value of the voice coil's pure resistance, voltage, current, heat loss, temperature, vibration amplitude, etc. Intensity Detection is a function that calculates the control variables required to control the allowable limit of each factor based on the calculated values of voltage, current, heat loss, temperature, and vibration amplitude.
Calculation formulas and parameters required for control are determined by design.

The function of suppressing the voltage of the voice coil or the output voltage of the power amplifier is controlled by Kv so that the amplitude of the voltage does not exceed the allowable value so that the output of the power amplifier does not saturate. The essence of the present invention is not voltage suppression inside the signal processing system but voltage suppression as a part of the operation state of the entire reproduction apparatus.

The voice coil current or power amplifier output current suppression function is controlled by Ki so that the current stays below the allowable value. The essence of the present invention is not the suppression of the amplitude inside the signal processing system, but the suppression of the current as a part of the operation state of the entire reproducing apparatus.

Kp is controlled so that the power consumption of the voice coil falls below the allowable value.
Kq is controlled so that the temperature or temperature rise of the voice coil stays below the allowable value.

Kd is controlled so that the vibration amplitude of the voice coil falls below the allowable value.
The suppression of the vibration amplitude of the voice coil does not control the magnitude of the signal, but causes the low-frequency cutoff filter to function and has a large effect on the lower frequency. Many songs have strong bass signals recorded. However, in normal listening at a signal level that is not so large, it is desirable to be able to reproduce to the maximum extent possible in the low frequency range. For this reason, it is effective to suppress the vibration amplitude by controlling the cutoff frequency of the bass cutoff filter LCd {f, Kd}.
There is no priority level for any of the suppression factors, and the factors that try to exceed
Suppression works by calculating K (f) = Kv * Ki * Kp * Kq * LCd {f, Kd}.
Vmax, Imax, Pmax, Qmax, and Dmax are determined in design based on the permissible limit values of the power amplifier and the speaker system, based on product planning and reliability design policies.
Kvmin, Kvmax, Kimin, Kimax, Kpmin, Kpmax, Kqmin, Kqmax are
It is designed and determined depending on Vmax, Imax, Pmax, Qmax, and Dmax.

Tva, Tvr, Tia, Tir, Tpa, Tpr, Tda, and Tdr are each determined by design according to the nature of the signal to be suppressed.
In general, the time constants of the fast attack time and the slow release time are appropriate for hearing.
The following values are guidelines as reference examples of attack time.
When Tva is less than about 10 msec, intermodulation distortion caused by saturation due to overvoltage is sensitive to hearing.
When Tia is less than about 100msec, short-time overcurrent is not sensitive to hearing.
When Tpa is less than about 1sec, the voice coil has heat capacity and short-time overpower is not a problem.
When Tda is about 10msec or less, the over-amplitude of the speaker system is sensitive to hearing as intermodulation distortion.
The standard for Tvr, Tir, Tpr, and Tdr is 1.5 to 30 seconds each.
It is necessary to minimize the uncomfortable feeling of the gain change, which is a by-product of the suppression function.
By assigning the time constants of the plurality of suppression functions to high speed and low speed, the uncomfortable feeling can be reduced. For example, voltage suppression is set to high speed, and current suppression is set to low speed. Furthermore, by applying two types of high speed and low speed to one suppression function, this uncomfortable feeling can be greatly reduced.

The detection of the temperature rise q (t) requires a calculation model that includes strictly complicated nonlinearities depending on the heat capacity and heat radiation conditions. However, in practice, a simple linear calculation model based on actual measurement values works well.
Jq (f) can model the square root of the intensity of the frequency characteristic of the temperature rise with a combination of first and second order filters.
Tq (f) is a characteristic under a heat radiation condition having a large thermal time constant. The temperature of the voice coil can be calculated by convolution integration with time-varying heat loss using the characteristic of the time lapse of the temperature rise as the integration nucleus of the impulse response characteristic.
The specific calculation formula is determined by design.
The calculation of the heat loss of the voice coil, which is the reference for temperature rise, uses a calculation model that takes into account the effect of the temperature rise of the voice coil's pure resistance. It can be calculated with sufficient accuracy.

Int {v (t)}, Int {i (t)}, Int {p (t)}, Int {d (t)} are voltage strength, current strength,
Heat loss intensity and vibration amplitude intensity.
The procedure for calculating each strength is determined by design.
Since it is necessary to detect the maximum instantaneous value,
Use the maximum absolute value of v (t), i (t), p (t), d (t).

FIG. 6 is an explanatory diagram of a measuring device having a function of obtaining main parameters of the setting parameters of FIG. 5 by automatic measurement and calculation.
In recent years, since most power amplifiers of small speaker systems have balanced outputs, the voltage detection portion is of a balanced type. An unbalanced type is acceptable as long as it can be measured without errors. rs is a current detection resistor having a small resistance value for current detection. By detecting the differential voltage across rs, the current supplied to the voice coil can be measured.
If the resistance of the voice coil is 4 ohms, the required value of rs can be 0.1 ohms for the required measurement.

DS measures the displacement of the voice coil.
For measuring the characteristics of the vibration amplitude, a white noise, an M-sequence random signal, or a signal that sweeps a sine wave is used.
Supply this signal to the power amplifier, or supply the measurement signal from the input terminal,
It can also be measured by setting H (f) and k (f) to 1 constantly.

G {f, q (t)} is a signal obtained by performing a fast Fourier transform of the voltage signal across the voice coil,
It can be obtained by dividing the measurement signal by the signal subjected to the fast Fourier transform.
Y {f, KRq, R, q (t)} is a signal obtained by subjecting the current signal of the voice coil to a fast Fourier transform,
It is obtained by dividing the measurement signal by the signal subjected to the fast Fourier transform.
In both G {f} and Y (f), the phase information is insignificant and can be ignored. Therefore, it is sufficient to calculate only the size. The calculation formulas reflecting the effect of the temperature rise q (t) of the voice coil of G {}, Y {} need not be a calculation formula expressed precisely and continuously.
By using the absolute value of the actual measurement value of G {f}, Y {f} at the temperature q (t) of a practically necessary and sufficient number of samples, sufficient accuracy is obtained by complementation between adjacent samples in practical use. Device can be realized.

R is the minimum value Fzmin of ABS {G (f, q (t)) / Y {f, q (t)}}.
There may be multiple minimum points Fzmin. In this case,
Select the minimum value of ABS {G (f, q (t)) / Y {f, q (t)}} at the minimum point.
The normal speaker Fzmin lies between 40Hz and 200Hz.

D {f, KRq, R, q (t)} is a signal obtained by performing a fast Fourier transform of the vibration amplitude of the voice coil,
It is obtained by dividing the test signal by the signal subjected to the fast Fourier transform.
The vibration amplitude of the voice coil is also affected by each component based on the temperature of the voice coil.
The calculation formula reflecting the effect of the temperature rise q (t) of the voice coil of D {} does not need to be a calculation formula accurately and continuously expressed.
By using the absolute value of the measured value of D {f, Kd} at a temperature q (t) of a practically necessary and sufficient number of samples, a device with practically sufficient accuracy can be realized.

Jq (f) is the frequency characteristic of the square root of the magnitude of the frequency characteristic of the temperature or the temperature rise value for each sampling frequency when a constant current is applied to the voice coil with the signal of the sampling frequency. The reason for the square root is that the power that causes the temperature rise of the voice coil in the subsequent calculation is r (t) * ｛i (t) * Jq (f)｝ ^ 2.
Because the temperature rise of the voice coil also depends on the vibration amplitude of the voice coil, the temperature rise also depends on the frequency of the voice coil current. In principle, Jp (f) is not a correction factor for the current, but this simplified calculation can provide sufficient accuracy for practical use.

Tq (f) is a time constant of temperature rise when a constant current is applied to the voice coil.
The temperature rise depends on the heat capacity and the heat radiation conditions, and is not necessarily a linear system, but is not necessarily linear. However, even if it is calculated as a linear concentrated constant system, no practically inconvenient error occurs.

FIG. 7 is a block diagram for explaining a system in which the reproduction system is divided into bands.
It is explanatory drawing corresponding to Claim 5.
An example is shown in which the band is divided by four types of speaker systems, and two types of the speaker systems are connected to one system of power amplifier.
This system, for each band division system,
It has a common input signal s (t), a common sound quality finishing filter H (f), and a common overall suppression coefficient K (f) = K11 (f) * K12 (f) * K2 (f) * K3 (f) .
K11 is a suppression coefficient corresponding to the speaker system 11 of the system 11;
K11 = Kv11 * Ki11 * Kp11 * Kq11 * LCq11 {f, Kd11}.
Kv11 * Ki11 * Kp11 * Kq11 * LCd11 {f, Kd11} is Kv, Ki, Kp, Kq, LCd (f, Kd) described in claim 1.
Respectively correspond to the voltage, current, heat loss, temperature, and vibration amplitude suppression coefficient of the voice coil.
Kv11 * Ki11 * Kp11 * Kq11 * LCd11 {f, Kd11} is an output of Intensity-Detection-11, and corresponds to Intensity-Detection of Claim 1.
The Signal-Detection-11 calculates the pure resistance, voltage, current, heat loss, temperature, and vibration amplitude of the voice coil in accordance with the Intensity-Detection of the first aspect, and calculates the calculated values. Pass to 11.
The input signal of Signal-Detection-11 is s (t) * H (f) * K (f) as in claim 1.
The parameters determined by design, which are required by the Intensity-Detection-11 and the Signal-Detection-11, are preliminarily incorporated into the system as in the first aspect.

K12 is a suppression coefficient corresponding to the speaker system 12 of the system 12.
K2 is a suppression coefficient corresponding to the speaker system 2 of the system 2.
K3 is a suppression coefficient corresponding to the speaker system 3 of the system 3.
Intensity-Detection-12, Intensity-Detection-2, and Intensity-Detection-3 are suppression coefficients for each subband,
Signal-Detection-12, Signal-Detection-2, Signal-Detection-3 are detection signals in calculation of each divided band,
Parameter-Set-12, Parameter-Set-2, and Parameter-Set-3 are parameters required for signal detection calculation and strength calculation of each divided band.

It is a basic configuration of the present invention. All of them relate to a method of greatly increasing the degree of freedom in designing a small speaker system using a plurality of known techniques.
From the characteristics of the entire playback device, calculate the voltage, current, heat loss, temperature, and vibration amplitude of the voice coil by calculation, detect the state of each factor, and ensure that each factor does not exceed the allowable limit. Suppress the strength of each factor.
G {}, Y {}, D {} are each affected by the temperature of the voice coil. The actual measured value of the voice coil's pure resistance Ra in a specific temperature environment Qa is incorporated in the calculation process as a parameter required for the present invention in advance. When information on the environmental temperature of the voice coil is given from outside, the temperature of the voice coil obtained by the calculation according to the present invention can be calculated.

A second aspect of the present invention relates to a method and apparatus for automatic parameter generation that enables simple and accurate setting of complicated parameters described in the first aspect at a design site.
The temperature of the voice coil greatly changes according to the operating conditions, and as a result, the pure resistance of the voice coil greatly changes. The task of knowing the temperature of the voice coil is important for accurately understanding the operating state of the speaker system.
To calculate the temperature of the voice coil, it is necessary to know the relationship between the current of the environmental voice coil, the value of the pure resistance of the voice coil, and the thermal time constant. In addition, the influence on the heat radiation condition that depends on the vibration amplitude of the voice coil must be considered. Unless the product is equipped with a function of measuring the voltage and current of the operating voice coil, it is not possible to directly grasp the driving situation.
For the temperature rise described in claim 1, the temperature q (t) of the voice coil is estimated by a design formula determined using a parameter group actually measured in advance. Based on the estimated temperature of the voice coil, G {f}, Y {f}, D {f} and the temperature q (t) are also incorporated into the calculation formula and calculated.

Although the voltage and current of the voice coil with respect to the input of the power amplifier greatly depend on the pure resistance of the voice coil, the calculation model of G ({f} and Y {f} The change in resistance due to coil temperature must be reflected, the temperature of the voice coil required for these formulas is also a calculated value, and a series of results in which the calculated temperature value forms a closed loop. There is a concern that the calculation error due to the positive feedback or the negative feedback may further increase due to the calculation error of q (t) because it is included in the calculation of the ambient temperature. Since the function of measuring the temperature rise of the voice coil and the temperature of the voice coil is provided, it is possible to evaluate the error of the entire calculation processing based on claim 1. That is, the temperature estimated by the calculation. It is possible to verify whether there is a discrepancy between the voltage and current values of the voice coil calculated by the above and the measured voltage and current values.If the discrepancy is larger than expected, And the opportunity to review the formulas.
The values of G {f}, Y {f}, D {f} due to the rise in temperature of the voice coil are measured discretely using sample values of temperature, and the results obtained at all sample temperatures are sent to the playback device. hand over.

A third aspect of the present invention relates to a method of determining the specifications of the maximum output voltage of the power amplifier and the impedance of the speaker system in the case of the design of the conventional reproducing apparatus.
By maximizing the capability of the speaker system and operating it constantly within the safe area according to the method of claim 1, the output voltage of the power amplifier can be greatly increased without being bound by the conventional practice, or the speaker system The present invention relates to a technique capable of significantly reducing the impedance of a voice coil.

The supplementary explanation of claim 4 is based on the fact that a closed loop including itself is formed in the calculation process of r (t) and q (t) described in claim 1 through the calculation of i (t). It relates to the function of suppressing the expansion of calculation errors.

Supplementary explanation of claim 5 The present invention relates to an application of claim 1 in a case where a plurality of power amplifiers and speaker systems are provided and divided into bands. The filter for band division for each band is integrated with the power amplifier.
For each speaker system, parameter group and voice coil pure resistance, voltage, current,
It has a function of calculating signal detection and a function of calculating suppression coefficients for heat loss, temperature, and vibration amplitude. When multiple speaker systems are connected to a single power amplifier, the operating state is detected for each speaker system in a state where the power amplifier and each speaker system are combined, and the suppression coefficient is determined based on each allowable value. Is calculated.
The total suppression coefficient is a product of suppression coefficients calculated for each speaker system.
The inputs of all the power amplifiers are common, and the common signal is subjected to the sound quality finishing filter and the overall suppression coefficient of the entire reproduction system and supplied to the respective power amplifiers.
All operations in the case of band division are based on the operations described in claim 1.

Figure 1
Of the speaker system under test,
Impedance impedance characteristics
SPL by Voltage Amplifier SPL by voltage output power amplifier
SPL by Current Amplifier SPL by current output power amplifier

FIG.
Of the speaker system under test,
Voltage drive Displacement Vibration of voice coil by voltage drive
Current drive Displacement Vibration of voice coil by current drive

FIG.
Of the speaker system under test,
Admitance Admittance characteristics
By Secondary EQ Approximation by eight secondary filters

FIG.
The approximation characteristic of FIG.
EQ1, Eq2 ,,,,,,, EQ12 12 secondary filters
Gain Total gain characteristics of eight secondary filters
Pahse Total phase characteristics of eight second-order filters

FIG.
s (t) playback signal
Tone Conditioning sound quality finish
H (f) sound quality finishing filter
e (t) Output of sound quality finishing filter
K (f) = Kv * Ki * Kp * Kq * LCd (f, Kd) Total suppression coefficient
Power Amp Power amplifier
Speaker System Speaker System
SP speaker unit
Resonance resonator
e (t) * K (f) Power amplifier input
Ra Voice coil net resistance reference value (at ambient temperature Qa)
Environmental temperature when Qa Ra is determined
Qe environmental temperature every moment
Qs environmental temperature detection
KRq Voice coil temperature coefficient of resistance
Minimal impedance of Fzmin voice coil
r (t) = {1 + KRq * q (t)} * R Voice coil resistance with corrected voice coil temperature
G {f, q (t)} Voltage frequency characteristics of voice coil to input of power amplifier
Y {f, q (t)} Current frequency characteristics of voice coil for power amplifier input
Jq (f) The temperature of the voice coil that depends on the signal frequency
Coefficient to be corrected by current conversion
Tq (f) Voice coil thermal time constant
D {f, q (t)} Vibration amplitude frequency characteristics of voice coil for power amplifier input
v (t) = e (t) * K (f) * G {f, q (t)} Calculated voice coil voltage
i (t) = e (t) * K (f) * Y {f, q (t)} Calculated voice coil current
p (t) = r (t) * {i (t)} ^ 2 Calculated heat loss of voice coil
q (t) = Qe + r (t) * {i (t) * J (f)} ^ 2 * Tp (f) Calculated voice coil temperature
d (t) = e (t) * K (f) * D {f, q (t)} Calculation of amplitude oscillation of voice coil
Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax｝ Voltage intensity suppression coefficient
Ki = Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax} Current intensity suppression coefficient
Kp = Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax} Heat loss strength loss suppression coefficient
Kq = Kq {q (t), Kqmin, Kqmax, Qmax} Temperature intensity suppression coefficient
Kd = Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax) Vibration amplitude intensity suppression coefficient
Tva, Tvr Attack time and release time for voltage strength measurement
Kvmin, Kvmax, Vmax Lower and upper limits of voltage intensity suppression coefficient, allowable voltage intensity
Tia, Tir Attack time and release time of current intensity measurement
Kimin, Kimax, Imax Lower and upper limits of current intensity suppression coefficient, allowable current intensity
Tpa, Tpr Attack time and release time for power intensity measurement
Kpmin, Kpmax, Pmax Lower and upper limits of power intensity suppression coefficient, allowable power intensity
Kqmin, Kqmax, Qmax Lower and upper limit of temperature intensity suppression coefficient, allowable temperature intensity
Tda, Tdr Attack time and release time of vibration amplitude intensity measurement
Kdmin, Kdmax, Dmax Lower and upper limits of vibration amplitude intensity suppression coefficient, allowable vibration amplitude intensity

FIG.
Measurement Equipment Parameter Measurement Tool
Displacement Sencer Voice coil vibration amplitude sensor
DS vibration amplitude sensor
Displacement Vibration amplitude measurement input
Test Signal Signal output for measurement
Voltage Voltage measurement input
Current Current measurement input
rs Current detection resistor
Dislacement Vibration amplitude measurement input
Measurment {G {f, q (t)}, Y {f, q (t)}, Ra, Qa, Jq (f), Tq (f), D {f, q (t)}}
Output of measured parameters

FIG.
K11 (f), K12 (f), K2 (f), K3 (f) Power amplifiers and speakers for each divided band
Suppression coefficient for each band corresponding to
K (f) = K11 (f) * K12 (f) * K2 (f) * K3 (f) Overall suppression coefficient
Power-Amp-1, Power-Amp-2, Power-Amp-3
Power amplifier with built-in split filter for each split band
H1 (f), H2 (f), H3 (f) Split characteristics for each split band
PA-1, PA-2, PA-3 Power amplifier for each divided band
Speaker-System-11 1st speaker system with split band 1
Speaker-System-12 Second speaker system with split band 1
Speaker-System-2 Split-band 2 speaker system
Speaker-System-3 Speaker system with 3 split bands
Parameter-set-1, Parameter-set-1, Parameter-set-1
Parameter group for each sub-band
Signal-Detection-1, Signal-Detection-2, Signal-Detection-3
Signal detection for each sub-band
Intensity-Detection-1, Intensity-Detection-2, Intensity-Detection-3
Intensity detection for each sub-band

Claims (5)

To the full potential of a sound reproduction system with a small speaker system, and
Regarding the method and playback device to safely withdraw,
;
Although the reproduction system has a wide band of practically 50 Hz to 300 times as large as 15000 Hz, the problem of a significant improvement in the performance of a high-quality power conversion system related to hearing is well known, but the relationship is intricately intertwined and conflicts. A method and apparatus for calculating certain individual phenomena by calculation and controlling them collectively and precisely to ensure reliability and significantly improve performance.
;
A playback signal is a signal that plays music or broadcast sound.
If the signal to be reproduced is a compressed signal, the demodulated signal is used as a reproduced signal,
The frequency range of the audio signal shall be in the practical sound frequency range,
Intensity is a measure of intensity based on the absolute, maximum, or rms value of a signal.
;
The speaker unit is a function to convert an electric signal to an acoustic signal,
A cabinet is a case that incorporates a speaker unit, and a resonator is one or both of an air vibration resonator and a mechanical vibration resonator that resonate by the transfer of energy due to the voice coil vibration of the speaker unit. ,
A speaker system is a device that combines one or more speaker units, one or more resonators, and one cabinet,
A power amplifier is a power amplifier that drives a speaker system,
The voice coil voltage and current are the same as the input voltage and input current of the speaker system, and the output voltage and output current of the power amplifier are also the same.
The heat loss of the voice coil is the same as the power loss generated by the current flowing through the voice coil and the pure resistance of the voice coil,
;
What is signal conversion?
Fast Fourier transform and its inverse, which have a resolution suitable for the use of acoustic signals,
Signal conversion by a filter having a specific frequency characteristic based on a combination of primary and secondary filters, and signal conversion by a convolution using an impulse response characteristic as an integration kernel;
Shall mean
In the following description, the frequency-dependent expression format represented by X (f), which has the function of signal conversion, is based on the combination of a first-order filter and a second-order filter group, generally called an equalizer. The frequency characteristics that approximate X (f) with sufficient accuracy for practical use are also included.
;
The impedance increase band is
In the bass range,
The interaction between the characteristic of the resonance, which is determined by the characteristic characteristic of the speaker unit and the volume of the cabinet, and the characteristic resonance characteristic of the resonator, or the operation that is independent of both,
And it is a frequency band where the impedance increases by being designed by calculating the resonance condition or by experimental correction,
In the treble range,
It is a frequency band where the impedance increases with the increase in frequency due to the inductance of the speaker unit generated from the voice coil and the surrounding magnetic circuit,
;
As described below,
t is time
f is the frequency,
Let s (t) be the playback signal,
Ra and Qa are the temperature Qa at the measurement time of the pure resistance Ra of the voice coil,
KRq is the temperature coefficient of the voice coil resistance,
q (t) is the voice coil temperature in the calculation described later,
Ra and KRq are constants determined by design,
Qa is the measured ambient temperature or the ambient temperature determined by design if not measured,
;
The symbol * is the multiplication of the left and right terms of *,
The symbol / is the division of the left and right terms of /
The symbol ｛｝ ^ 2 is the square of the term {},
What is x (t) * X (f)
It is assumed that a time series signal x (t) is a time series signal converted by a system having a frequency characteristic of X (f),
x (t)
s (t), e (t), r (t), v (t), i (t), p (t), q (t), d (t)
X (f)
H (f), K (f), G {f, q (t)}, Y {f, q (t)}, Jq (f), Tq (f), D {f, q (t)}, LCd {f, Kd}
And a frequency-dependent constant that includes
;
H (f) is the sound quality finishing filter,
H (f) is responsible for signal conversion in order to obtain the expected sound quality of s (t) with the given combination of power amplifier and speaker system,
H (f) is a device designed on the premise that all the operating conditions of the regeneration system voltage, current, power, temperature and vibration amplitude are controlled to be within the allowable range, which is the essence of the present invention. It is a constant determined by design only for the overall sound quality finish,
e (t) is s (t) * H (f),
Let K (f) * e (t) be the input signal of the power amplifier,
K (f) is a comprehensive suppression coefficient, which will be described later, for the details of suppressing each strength so that the operation state of the reproduction system falls within the allowable range.
;
r (t) = {1 + KRq * {q (t) -Qa}} * Ra is the calculated voice coil net resistance at temperature q (t),
The function to calculate {1 + KRq * {q (t) -Qa}} * Ra is a voice coil pure resistance calculation function,
;
G {f, q (t)} is the voice coil voltage-frequency characteristic, and this value is the ratio of the voltage supplied to the speaker system to the input signal of the power amplifier,
G {f, q (t)} depends on the temperature rise q (t) of the voice coil,
The formula of G {f, q (t)} shall be obtained from actual measurement or determined by design,
;
Y {f, q (t)} is the voice coil current frequency characteristic, and this value is the ratio of the current supplied to the voice coil to the input signal of the power amplifier,
Y {f, q (t)} depends on the temperature rise q (t) of the voice coil,
The formula for calculating Y {f, q (t)} shall be obtained from actual measurements or determined by design,
;
D {f, q (t)} is the voice coil vibration amplitude frequency characteristic, and this value is the ratio of the voice coil vibration amplitude to the input signal of the power amplifier,
D {f, q (t)} depends on the temperature rise q (t) of the voice coil.
The formula of D {f, q (t)} is a constant obtained from actual measurement or determined by design,
;
v (t) = e (t) * K (f) * G {f, q (t)} is the calculated voice coil voltage when the input of the power amplifier is K (f) * e (t). ,
The function of calculating e (t) * K (f) * G {f, q (t)} is a voice coil voltage calculation function.
;
i (t) = e (t) * K (f) * Y {f, q (t)} is the calculated voice coil current when the input of the power amplifier is K (f) * e (t). ,
The function of calculating e (t) * K (f) * Y {f, q (t)} is a voice coil current calculation function.
;
p (t) = r (t) * {i (t)} ^ 2 is the calculated voice coil heat loss,
The function of calculating r (t) * {i (t)} ^ 2 is the voice coil heat loss calculation function.
;
q (t) = r (t) * {i (t) * J (f)} ^ 2 * Tp (f) is the calculated voice coil temperature,
The function of calculating r (t) * {i (t) * J (f)} ^ 2 * Tq (f) is a voice coil temperature calculation function.
Jq (f) is a current conversion temperature correction coefficient, which has a role of converting a correction coefficient of a voice coil temperature rise due to an effect of heat radiation conditions depending on a vibration amplitude of the voice coil into a current value,
Faithful modeling of the mechanism of heat radiation conditions that depends on the vibration amplitude of the voice coil is a method that approximates with a simple calculation formula because the calculation formula is complicated because the system has nonlinear elements. And incorporate Jq (f) into the calculation model as a factor that multiplies the magnitude of the current having frequency characteristics.
Tq (f) is the thermal time constant of the voice coil under the heat radiation condition with a large thermal time constant including the peripheral parts supporting the voice coil structure,
The formulas and constants for Jq (f) and Tq (f) shall be obtained from actual measurements or determined by design,
The value of q (t) shall be reflected in the calculation of v (t), i (t), p (t), d (t),
The calculation of q (t) forms a closed loop through the calculation of i (t) and p (t), but the thermal time constant, one of the parameters of q (t), is large, and q (t) Since the increase in t) is reflected in the decrease in the intensity of i (t), p (t), we use the property that the closed loop involving q (t) does not diverge,
;
d (t) = e (t) * K (f) * D {f, q (t)} is the calculated vibration amplitude of the voice coil when the input of the power amplifier is K (f) * e (t) age,
The function of calculating e (t) * K (f) * D {f, q (t)} is a voice coil vibration amplitude calculation function,
The formula of D {f, q (t)} shall be obtained from actual measurement or determined by design,
;
K (f) = Kv * Ki * Kp * Kq * LCd {f, Kd} is a variable coefficient that controls the strength of the voltage, current, heat loss, temperature, and vibration amplitude of the voice coil within the allowable range. So,
When the voltage intensity suppression coefficient is Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax｝,
The current intensity suppression coefficient is Ki = Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax},
The heat loss strength loss suppression coefficient is Kp = Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax},
The temperature intensity suppression coefficient is Kq = Kq {{q (t)}, Kqmin, Kqmax, Qmax},
The vibration amplitude intensity suppression coefficient is Kd = Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax),
Shall be calculated by
The function of calculating Kv * Ki * Kp * Kq * LCd {f, Kd} is the total suppression coefficient calculation function,
;
Kv = Kv {Int {v (t)}, Tva, Tvr, Kvmin, Kvmax, Vmax} is a variable coefficient that varies from Kvmin to Kvmax,
The function that governs the calculation of Kv {} is the voltage suppression coefficient calculation function,
Int {v (t)｝ is the calculated intensity signal of the voice coil voltage v (t),
If the maximum value of Int {v (t)} is smaller than Vmax, Kv = Kmax; otherwise, the value of Kv shall be varied so that the value of Int {v (t)} does not exceed Vmax. ,
Kv acts on the voltage intensity signal Int {v (t)} with an attack time constant Tva and a release time constant Tvr,
The values of Tva, Tvr, Kvmin, Kvmax, Vmax are constants determined by design,
The formula for calculating Kv {} shall be determined by design,
;
Ki {Int {i (t)}, Tia, Tir, Kimin, Kimax, Imax} is
Ki {} is a variable coefficient that varies from Kimin to Kimax,
The function that controls the calculation of Ki {} is the current suppression coefficient calculation function,
Int {i (t)｝ is the intensity signal of the calculated voice coil current i (t),
If the maximum value of Int {i (t)} is smaller than Imax, then Ki = Kimax; otherwise, the value of Ki shall be variable so that the value of Int {i (t)} does not exceed Imax. ,
Ki acts on the voltage intensity signal Int {i (t)} with an attack time constant Tia and a release time constant Tir,
The values of Tia, Tir, Kimax, Kimin, Imax are constants determined by design,
The formula of Ki {} is determined by design,
;
Kp {Int {p (t)}, Tpa, Tpr, Kpmin, Kpmax, Pmax} is
Kp {} is a variable coefficient that varies from Kpmin to Kpmax,
The function responsible for calculating Kp {} is the heat loss suppression coefficient calculation function,
Int {p (t)｝ is the intensity signal of the calculated heat loss p (t) of the voice coil,
If the maximum value of Int {p (t)} is smaller than Pmax, Kp = Kpmax; otherwise, change the value of Kp so that the value of Int {p (t)} does not exceed Pmax. ,
Kp acts on the power intensity signal of Int {p (t)} with an attack time constant Tpa and a release time constant Tpr,
The values of Tpa, Tpr, Kpmax, Kpmin, Pmax are constants determined by design,
The formula for calculating Kp {} shall be determined by design,
;
Kq {q (t), Tq (f), Kqmin, Kqmax, Qmax} is
Kq {} is a variable coefficient that varies from Kqmin to Kqmax,
The function that controls the calculation of Kq {} is the temperature suppression coefficient calculation function,
q (t) is the voice coil temperature in the above calculation,
If the maximum value of q (t) is smaller than Qmax, Kq = Kqmax; otherwise, the value of Kq shall be variable so that the value of q (t) does not exceed Qmax,
The values of Kqmax, Kqmin, Qmax are constants determined by design,
The formula of Kq {} shall be determined by design,
;
Kd {Int {d (t)}, Tda, Tdr, Kdmin, Kdmax, Dmax} is
Kd {} is a variable coefficient that varies from Kdmin to Kdmax,
The function that controls the calculation of Kd {} is the vibration amplitude suppression coefficient calculation function,
Int {d (t)｝ is the calculated intensity signal of the voice coil vibration amplitude d (t),
Kd {} acts on the temperature intensity signal Int {d (t)} with an attack constant Tda and a release time constant Tdr,
Kd {} is a suppression coefficient for controlling a cutoff frequency of a variable filter having a first-order or second-order low-frequency cutoff characteristic, which limits a maximum value of a vibration amplitude intensity of a calculated voice coil,
The function that controls the calculation of Kd {} is the vibration amplitude suppression coefficient calculation function,
The value that determines the minimum frequency of the cutoff frequency is Kdmin, the value that determines the maximum frequency is Kdmax,
When Int {d (t)} is below the tolerance Dmax, Kd () = Kdmin and in other cases
The value of K {} shall be variable such that Int {d (t)} does not exceed the allowable value Dmax,
The values of Tda, Tdr, Kdmax, Kdmin, Dmax are constants determined by design,
The formula for calculating Kd {} shall be determined by design,
;
Each of Kv, Ki, Kp, Kq, LCd {f, Kd} shall function independently,
Of Kv, Ki, Kp, Kq, LCd {f, Kd}, the suppression function to be operated and the suppression function not to be operated depending on the application shall be determined by design,
The suppression factor that does not function is constantly set to 1,
;
First, having a sound quality finishing filter H (f),
Of voice coil,
The second is to have a pure resistance calculation function,
The third is to have a voltage calculation function and a voltage suppression coefficient calculation function,
Fourth, having a current calculation function and a current suppression coefficient calculation function,
Fifth, having a heat loss calculation function and a heat loss suppression coefficient calculation function,
The sixth is to have a temperature calculation function and a temperature suppression coefficient calculation function,
Seventh, having a vibration amplitude calculation function and a vibration amplitude suppression coefficient calculation function,
The eighth is to have a total suppression coefficient calculation function,
;
Both are known,
Any one, or any two, or all of the first, second, third, fourth, and fifth,
By combining the fifth, sixth, and eighth, the operating state of the sound reproduction system is estimated by calculation, and within the allowable operation range, the reproduction capability of the sound reproduction system is maximized. Sound signal control method and playback device. The sound signal reproducing method and the reproducing device according to claim 1, characterized in that the reproducing capability of the sound reproducing device is maximized.
Measurement of parameters that take a long time,
Converting the measurement result into an expression form of parameters necessary for incorporating in the calculation formula of claim 1;
Said the method and apparatus for automation of improving the environment for the determination of parameters that required complex tasks for the design site.
;
The terms described in claim 1 shall apply,
ABS {} is the absolute value in ｛｝,
;
Ra is the actual measured value of the voice coil's pure resistance at the measured ambient temperature Qa.
;
The function of converting the difference voltage between the two output terminals connected from the power amplifier to the speaker system to a digital signal is a voltage measurement function,
The signal output by the voltage measurement function is vo (t),
;
On one of the two wires connecting the power amplifier to the speaker system,
Connect a resistor for current detection with a small resistance value compared to the inherent impedance of the speaker system,
By converting the difference voltage between the voltages across the resistor into a digital signal,
The function of measuring the current flowing through the speaker system is the current measurement function,
The signal output by the current measurement function is io (t),
;
The function of detecting the vibration of the central part of the cone of the speaker system and converting the detected vibration amplitude signal to a digital signal is a vibration amplitude measurement function.
The signal output by the vibration amplitude measurement function is xo (t),
;
Assuming that the measurement signal is used for s (t),
The measurement signal is one of white noise, M-sequence, and sine wave sweep,
Let S (f) be the signal representing s (t) on the frequency axis,
Let H (f) be 1,
K (f) is always 1 and
The function of converting a time-series signal to a frequency signal described below uses a known fast Fourier transform,
;
A signal expressing vo (t) obtained by measurement from s (t), which is a known signal, on the frequency axis
Vo (f)
The function to calculate Go (f) = Vo (f) / S (f) is a voice coil voltage frequency characteristic measurement function,
;
A signal that represents io (t) obtained by measurement from s (t), which is a known signal, on the frequency axis
Io (f),
The function to calculate Yo (f) = Io (f) / S (f) is a voice coil current frequency characteristic measurement function.
;
A signal that expresses xo (t) obtained by measurement from the known signal s (t) on the frequency axis
Xo (f),
The function to calculate Do (f) = Xo (f) / S (f) is a voice coil vibration amplitude frequency characteristic measurement function,
;
The frequency at which the strength of ABS {Vo (f) / Io (f)} is minimal within the frequency range determined by design
Fzmin,
The function to detect Fzmin is a voice coil minimum impedance frequency detection function,
Let ABS {Vo (f) / Io (f)} at Fzmin be Rmin,
The function to obtain Rmin is the voice coil resistance measurement function,
Let q (t) be the voice coil temperature calculated from Rmin, Qa and Ra,
The formula for calculating q (t) shall be determined by design, and
The function to calculate q (t) is a voice coil temperature calculation function,
;
Using the fact that the value of Rmin at Fzmin depends on the temperature of the voice coil, the strength of s (t) in the time interval during which the voice coil temperature measurement function operates is based on the known temperature coefficient of resistance of the voice coil. S (t) of strength that does not affect the practically necessary and sufficient accuracy of coil temperature measurement,
The intensity of s (t) for the measurement and the measurement time shall be determined by design,
;
G {f, q (t)} and Y {f, q (t)} are
Let G {f}, Y {f)} depend on the voice coil temperature q (t),
The current intensity of the voice coil required to obtain the sample data for G {f, q (t)} and Y {f, q (t)} described in claim 1 is represented by Io1, Io2, Io3,, Ion, ,, Iou
In Ion where n = 1,2,3 ,,,,, u
Let G {f, q (t)} be G1 {f}, G2 {f}, G3 {f} ,, Gn {f} ,, Gu {f},
Let Y {f, q (t)} be Y1 {f}, Y2 {f}, Y3 {f} ,,, Yn {f} ,, Yu {f}
Let D {f, q (t)} be D1 {f}, D2 {f}, D3 {f} ,, Dn {f} ,, Du {f},
Gn (f), Yn (f), and Dn (f) at each Ion where n = 1, 2, 3, ..., u
Temperature-dependent voltage-frequency characteristics group,
Temperature-dependent current-frequency characteristics group,
Temperature dependent vibration amplitude frequency characteristics group,
Each of these characteristic groups shall be subjected to a calculation reflecting the temperature of the voice coil in the function for controlling the calculation of v (t), i (t), d (t) described in claim 1,
Each of the functions for obtaining these characteristic groups is a temperature-dependent voltage-frequency characteristic group measurement function,
Temperature dependent current frequency characteristics group measurement function,
Temperature dependent vibration amplitude frequency characteristics group measurement function,
The number of samples of the current intensity is practically determined by design as a necessary and sufficient number to secure the accuracy of the temperature influence of the characteristics,
;
Let f1, f2, f3 ,,, fn ,,, fb be the sample frequencies required to obtain the sample data of the voice amplitude frequency characteristics D {f, q (t)} that depend on the voice coil temperature q (t). ,
Let t1, t2, t3 ,, tm ,,, tc be the sample time for the purpose of measuring the factor depending on the elapsed time of the voice coil temperature, starting from the state of the environmental temperature Qa,
In the temperature measurement section, Io (t) of constant strength required for measurement shall be supplied to the voice coil,
The number of sample frequencies and sample times shall be determined by design,
A sample group of voice coil temperatures obtained by measurement at each sample time
where n 1,2,3 ,,, b and m is 1,2,3 ,,,, c
Temp {fn, tm},
Temp {fn, tm} is the measurement result under the condition that the intensity of Io (t) is controlled to a constant value in real time for each sample frequency,
where n and m are data numbers determined by design,
The temperature of the voice coil depending on the vibration frequency at time tm is
Temp-1m, Temp-2m, Temp-3m ,,, Temp-nm ,,, Temp-bm
The value obtained by dividing each temperature value by Temp-nm
Ratio-1m, Ratio-2m, Ratio-3m ,,, Ratio-nm ,,,, Ratiobm,
Jqo (f) is the approximate characteristic of the frequency characteristic plotting the square root of this value on the frequency axis,
Jqo (f) is the voice coil current conversion temperature correction coefficient,
Let Jqo (f) be a constant referred to by the function responsible for calculating q (t) as Jq (f) described in claim 1,
The function to obtain Jqo (f) is a voice coil current conversion temperature correction coefficient calculation function,
;
Where n in the data group of Temp {fn, tm} is a data number determined by design,
The temperature of the voice coil that depends on the time lapse tm
Temp-n1, Temp-n2, Temp-n3 ,,, Temp-nm ,,, Temp-nc
Time-series data group obtained by dividing each temperature value by Temp-nc
Ratio-c1, Ratio-c2, Ratio-c3 ,,, Ratio-cn ,,,, Ratio-cb,
The time series data group most similar to this time series data group
{1-e ^-(t1 / A)}, {1-e ^-(t2 / A)}, {1-e ^-(t3 / A)} ,,, {1-e ^-(tm / A)} ,,, {1-e ^-(tc / A)}
The function to find A that satisfies is the voice coil thermal time constant calculation function,
where t is time and A is time constant
{1- {e ^-(t / A)}} * Temp-nc / {Int {Io (t)}} is the voice coil temperature transient response,
The time derivative of the temperature transient response
{e ^-(t / A)} * Temp-nc / {Int {Io (t)} * A} is the temperature impulse response of the voice coil,
The temperature frequency characteristic corresponding to the temperature transient response characteristic
where j is the imaginary unit and pai is the pi,
{Temp-nc / {Int {Io (t)} * A}} * {1 + j * 2 * pai / A} ^-1
One of the temperature impulse response characteristic and the temperature frequency characteristic is defined as Tq (f) required for calculating q (t) described in claim 1.
The function to calculate Tq (f) is a thermal time constant characteristic calculation function,
The formula for calculating Tq (f) shall be determined by design, and
The constant required to calculate q (t) in claim 1 is
When using the calculated temperature impulse response characteristics, as the integration kernel of the convolution integration,
When using temperature frequency characteristics,
The format determined by design shall be selected,
;
Of voice coil,
The first is to have a voltage measurement function,
Second, having a current measurement function,
Third, having a vibration amplitude measurement function,
The fourth is to have a voltage frequency characteristic measurement function,
Fifth, having a current frequency characteristic measurement function,
The sixth is to have a vibration amplitude frequency characteristic measurement function,
Seventh, having a minimum impedance detection function,
Eighth, having a resistance measurement function,
Ninth having temperature measurement function,
Having a temperature-dependent voltage-frequency characteristic group measurement function as a tenth,
Eleventh is to have a temperature-dependent current frequency characteristic group measurement function,
Having the temperature-dependent vibration amplitude frequency characteristic group measurement function as a twelfth,
Thirteenth, having a current conversion temperature correction coefficient calculation function,
Fourteenth, having a thermal time constant calculation function,
Fifteenth, having a function of calculating thermal time constant characteristics,
First, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth, and fifteenth,
Go {f, q (t)}, Yo {f, q (t)}, Joq (f), Toq (f), Do {f, q (t)} f, q (t)}, Y {f, q (t)}, Jq (f), Tq (f), D {f, q (t)}
A parameter group measurement device that has the function of outputting in correspondence with and outputting Fzmin. The terms described in claim 1 shall apply,
{} ^ 0.5 is the square root of the term ｛｝,
The impedance at the maximum point of the impedance increase band described in claim 1 is Zmax,
When the measured resistance value of the voice coil or the nominal impedance of the speaker unit is R,
ABS {Zmax / R} is A,
The actual measured maximum power or the nominal maximum power of the speaker system is Prated,
Let Vrated be the maximum effective distortion-free effective voltage output by the power amplifier,
;
The first method is to determine the distortion-free maximum output effective voltage of the power amplifier based on the pure resistance R of the voice coil by calculating Vrated = {Prated * R * A} ^ 0.5,
;
By calculating Vrated = {Prated * R * A} ^ 0.5, the distortion-free maximum output effective voltage of the power amplifier
The second method is to determine the pure resistance R or the nominal impedance of the voice coil based on Vrated.
;
When either of the first and second methods is adopted, in a frequency band where the impedance value of the speaker system is minimized,
In order to avoid the disadvantage that the maximum heat loss of the voice coil is A times larger than before,
Claim 1.
Of voice coil,
Third, having a pure resistance calculation function,
The fourth is to have a voltage calculation function and a voltage suppression coefficient calculation function,
Fifth, having a current calculation function and a current suppression coefficient calculation function,
Sixth, having a heat loss calculation function and a heat loss suppression coefficient calculation function,
Seventh, having a temperature calculation function and a temperature suppression coefficient calculation function,
Eighth, having a vibration amplitude calculation function and a vibration amplitude suppression coefficient calculation function,
The ninth is to have a total suppression coefficient calculation function,
Either the first or the second,
Both are known,
Any one, or any two, or all of the third and fourth, fifth, and sixth,
By combining the seventh, the eighth, and the ninth, the operation state of the sound reproduction system is estimated by calculation, and within the allowable operation range, the reproduction capability of the sound reproduction system is maximized. Sound signal control method and playback device. The terms described in claim 1 shall apply,
The property that any of r (t), q (t), and i (t) in the system for calculating r (t), q (t), i (t) according to claim 1 With regard to a method for reducing the influence on the calculation error due to having a series of calculation processes forming a closed loop,
Assuming that the calculated pure resistance of the voice coil is r (t) = {1 + KRq * {q (t) -Qa}} * Ra, the value calculated from the calculated voice coil temperature q (t) is
When verifying the proposition that it must match r (t), which can be calculated as the impedance at Fzmin, and detecting a deviation greater than a certain value,
Regarding the method of making some modifications, the method of claim 1
e (t) * K (f) * G {f, q (t)} = s (t) * H (f) * K (f) * G {f, q (t)} t) is the fast Fourier transformed signal is V (f), and
e (t) * K (f) * Y {f, q (t)} = s (t) * H (f) * K (f) * G {f, q (t)} t) is the fast Fourier transformed signal is I (f),
In the frequency range determined by design, the frequency at which the intensity of ABS {V (f) / I (f)} is the minimum value is defined as Fzmin, or Fzmin determined by design.
Let the intensity of v (t) be Int {v (t)},
Let the intensity of i (t) be Int {i (t)},
Let ABS {V (f) / I (f)} in Fzmin be rvi (t),
If {Int {r (t)}-Int {rvi (t)}} / Int {r (t)} exceeds the + Error value,
Make sure {Int {r (t)}-Int {rvi (t)}} / Int {r (t)} does not exceed the + Error value.
decrease the value of q (t),
If {Int {r (t)}-Int {rvi (t)}} / Int {r (t)} exceeds the value of -Error,
{Int {r (t)}-Int {rvi (t)}} / Int {r (t)} should not exceed the value of -Error.
increase the value of q (t),
A function to prevent r (t) and rvi (t) from deviating beyond a certain limit,
As a function to correct voice coil temperature in calculation,
The first is to have a voice coil temperature correction function in calculation,
Let qcomp (t) be the modified q (t),
A function to recalculate qcomp (t) as q (t) in claim 1
The voice coil temperature recalculation function on the calculator
The second is to have a voice coil temperature correction function in calculation,
In addition to claim 1,
A sound signal reproduction method comprising: estimating an operation state of a sound reproduction system having first and second by calculation and maximizing a reproduction capability of the sound reproduction system within an allowable operation range; and Playback device. The terms described in claim 1 shall apply,
Claim 1 is that the configuration of the power amplifier and the speaker system is the entire band,
Regarding the case where the entire band is divided into a plurality of bands to constitute a playback device,
s (t) is the input signal,
H (f) is the sound quality finishing filter,
K (f) is the total suppression factor,
The total suppression coefficient described in claim 1, which is calculated for each of the band-divided individual bands, is defined as a total suppression coefficient for each band,
;
In band division,
When one type of speaker system is connected to the band allocated to one system of power amplifier, the output of the filter for band division is connected to the input of the power amplifier,
And the input of the filter for band division,
Suppose that K (f) * e (t) = s (t) * H (f) * K (f) for the entire band.
The parameters that have the characteristics of the band splitting filter, power amplifier, and speaker system are the parameters necessary for calculating the instantaneous value and intensity of the pure resistance, voltage, current, heat loss, temperature, and vibration amplitude of the voice coil in that band. ,
The function of calculating the total suppression coefficient for each band of one band is the total suppression coefficient calculation function for each band,
;
When a plurality of types of speaker systems are connected to a band assigned to one power amplifier, an output of a filter for band division is connected to an input of the power amplifier,
And the input of the filter for band division,
Suppose that K (f) * e (t) = s (t) * H (f) * K (f) for the entire band.
A parameter group with the characteristics of the function consisting of a band splitting filter, a power amplifier, and one of multiple speaker systems,
Of the voice coil of the band with the speaker system,
The parameters required for calculating the instantaneous value and intensity of pure resistance, voltage, current, heat loss, temperature, and vibration amplitude
The function to calculate the total suppression coefficient for each band of the band of the system of the speaker system is the total suppression coefficient calculation function for each band,
One kind of band-based total suppression coefficient calculation function shall have one set of parameters,
Similarly, for other types of speaker systems, each speaker system shall have its own band-specific total suppression coefficient calculation function and parameters required for calculation,
All parameter groups shall be determined appropriately for design,
;
The output of the total suppression coefficient calculation function for each band corresponding to n speaker systems is
K1 (f), K2 (f), K3 (f) ,,, Kn (f)
K (f) is the product of the total suppression coefficient for each band calculated for each divided band, that is,
K (f) = K1 (f), K2 (f), K3 (f) ,,, Kn (f)
The sound signal reproducing method according to claim 1 is applied,
It has a band-based total suppression coefficient calculation function corresponding to each of a plurality of speaker systems,
The product of the total suppression coefficient for each band, which is the output of the total suppression coefficient calculation function for each band, is used as the total suppression coefficient.
Estimate the operation status of the sound reproduction system by calculation, and within the allowable operating range,
It is characterized by maximizing the reproduction capability of the sound reproduction system.
A band division acoustic signal control method and a reproducing apparatus.