CN1179862A - Audio bass speaker driver circuit - Google Patents

Abstract

A bass audio circuit includes a first filter network which receives left and right channel input signals and produces two filtered signals by attenuating frequencies in the input signals above a first cutoff frequency. The two filtered signals are summed to create a first monophonic signal. A second filter network produces attenuates frequencies in either the input signals or in the first monophonic signal that are above a second cutoff frequency which is lower than the first cutoff frequency. The signals from the second filter network are combined and passed through a phase inverter to derive a second monophonic signal. An output stage individually amplifies the two monophonic signals which then either are applied to a dual voice coil woofer, or are electrically summed and applied to a single voice coil woofer. Alternatively, the two monophonic signals are first summed and applied to a single channel amplifier which drives a single voice coil woofer. This audio circuit adjusts the relative emphasis of psychoacoustic elements of the bass signals to accurately emulate the bass performance of the sound being projected and enhances performance of a woofer driver by limiting extremely low frequency displacement.

Description

Audio bass speaker driver circuit

The cross reference that the application is correlated with

The application submitted the part renewal application that now resigned, application number is 07/875399 U.S. Patent application on April 29th, 1992.

The background of invention

Technical field

The present invention relates to the frequency filter system of sound system, relate in particular to the frequency filter of bass zone audio signal.

The discussion of correlation technique

In the past, various technology had been used to improve the bass response of high-fidelity and stereo component system.Typically, these systems comprise a loud speaker, and it has large-scale vibrating diaphragm and the long amplitude of oscillation of this vibrating diaphragm is to obtain the relatively large air that the low frequency desirable strength requires with the driving.People's attentiveness concentrates on and makes intensity and " dynamics " (punch) on the maximum, and other tonequality composition of the sound experience of bass zone is felt but inaudible undersonic frequency also takes in such as the audience.

But, the less attention of directivity and spatiality, this is owing to recognize for the sound wave that is lower than about 150Hz common imperceptible direction of people and sound source position.At this moment because low frequency has long relatively wavelength, for example the signal wavelength of 130Hz is 8.7 feet, and like this, bass frequencies are tended to non-directional.The sound of the upper frequency of 150Hz to 550Hz scope is more obviously felt directivity and spatiality, but this scope is not at woofer and loudspeaker enclosure thereof usually.As a result, usually two channel application of stereophonic sound system in the woofer of the single low frequency that calls woofer or sub-woofer speaker.This structure is sometimes referred to as " merging into single channel " (summing to mono).

The bass performance of speaker system depends on the design of its loudspeaker enclosure usually consumingly, for transmitting the better speaker performance of acquisition on intensity and the dynamics, has designed all kinds of loudspeaker enclosures.The representational improvement that causes increasing bass zone response and performance comprises basic infinite baffle loudspeaker enclosure, it is provided at the bass drivers that is installed in the large-scale loudspeaker enclosure on the baffle, and its mounting means makes the forward wave (frontwave) of the mobile vibrating diaphragm of driver keep isolating with backward wave (back wave).Another kind of development is suspension speaker (acousticsuspension speaker), and it uses the small infinite baffle formula loudspeaker enclosure that has loose suspension vibrating diaphragm, has very soft surround.Like this, according to vibrating diaphragm inwards and outwards motion, the expansion of air and be compressed with the motion that helps control vibrating diaphragm in the loudspeaker enclosure.This loud speaker is called the air suspension type, and does not have the vibrating diaphragm surround of further controlling rigidity when it when zero-bit is left.On the other hand, bass bass-reflex cabinet (being sometimes referred to as channel-type or vented enclosure) is indirect utilization backward wave energy by forming a mouth on the loud speaker, and this loudspeaker enclosure is that tuning (or customization size) is to produce the resonance from casing.This casing resonance be tuned to be lower than loud speaker resonance to provide lower bass response by the backward wave that utilizes loud speaker.

The design of other processing or improvement bass response comprises acoustic transmission line loud speaker, and it only forms the long path that starts from the woofer rear portion, to reduce from the sound level at loud speaker rear portion and the resonance of generation and loud speaker output coordinating.The trumpet type loudspeaker applications is connected directly to the large-scale loudspeaker of loud speaker front to improve the efficient of loud speaker.These loudspeaker have improved the coupling of loud speaker and surrounding air.Electrical equalization woofer (electronicallyequalized bass speaker) strengthens the bass signal level enter amplifier and loud speaker, the bass decay of the expection that can run into the compensation miniature loudspeaker.But this design has the defective of the bigger load of pair amplifier setting, and for this reason, independent low playback amplifier usually is configured in the system.

The expectation of louder, stronger and lower bass has produced the amplifier of particular design to improve the low frequency output of speaker system.These designs comprise to be used improved high power amplifier and notes power supply and improved damping coefficient (that is the ability of amplifier control loudspeaker action).Another kind of technology is to utilize servo feedback, wherein transducer invest converter and when driver is overdrived, do detection with this feedback information to amplifier.Amplifier instant reversal signal phase is to revise driver then.Another kind of approach is to wait laminated structure, and it uses peculiar (exotic) loudspeaker enclosure of more pattern and more converter.

After the characteristics of having looked back the simplification speaker system, can better understand the defective of present structure.In order to carry out this respect discussion, a frequency acoustic driver can be modeled as a piston source (piston source).Show " sound and structural vibration " 59 pages referring to Frank Fahy, far field pressure can be expressed as: $p(r,t)=-j{\mathrm{\ρ}}_0{\mathrm{cka}}^2{v}_n{e}^{\mathrm{j\ωt}}\left[\frac{2J_1\left(\mathrm{ka}\sin \left(\mathrm{\θ}\right)\right)}{\mathrm{ka}\sin \left(\mathrm{\θ}\right)}\right]\frac{e^{-\mathrm{jkr}}}{2r}---\left(1\right)$ In the formula: p is a far field pressure, and t is the time, and j is-1 square root, ρ ₀Be atmospheric density, c is a THE VELOCITY OF SOUND IN AIR, and k is the sound wave number, and a is the loud speaker piston diameter, and Vn is the speed of loud speaker piston, J ₁Be first kind first-order bessel function, θ is the angle from normal direction to the loud speaker piston face.This equation is done to rewrite and simplified by the pressure of observing the θ place of equalling zero again with the loud speaker piston displacement, can get following formula: $p(r,t)=-{\mathrm{\ω}}^2{\mathrm{\ρ}}_0{a}^2{\mathrm{de}}^{\mathrm{j\ωt}}\left[\frac{{2J}_1\left(\mathrm{ka}\right)}{\mathrm{ka}}\right]\frac{e^{-\mathrm{jkr}}}{2r}---\left(2\right)$

Function in the bracket for low-frequency approximation in 1, so for given piston, the pressure at specific range r place is proportional to the displacement d of the quadratic sum piston of frequency (ω).Like this, in order to obtain given sound pressure level (SPL), with frequency halving, the loud speaker piston displacement need increase by 4 times at every turn.People can not hear the sound that is lower than some frequency (between 20～40Hz), though present acoustical quality when feeling infrasound.Term used herein " infrasonic sound " is to describe the audio range be lower than the low-limit frequency that most of people can hear.Most sound systems allow the power amplifier transmission will be sent to the whole frequency range that is lower than this value of loud speaker.

Loud speaker has limited displacement range, and in this scope, its response remains linear function with input voltage.When input voltage was higher than this boundary, loud speaker (displacement) reached maximum (bottom-out), thereby caused that harmonic distortion increases.So the limit of loudspeaker displacement is controlled by inaudible very low frequency.These requirements are paid attention to by present bass device design and performance.In addition, to being placed on the stereo of the left and right side's sound source in audience the place ahead, the simulation of the sound performance that it is preferable further weakens for low frequency bass signal directivity with spatial related.

Brief summary of the invention

The purpose of this invention is to provide a kind of low system for electrical teaching, it regulates intensity, spatiality, directivity and reverberation composition so that tonequality impression true to nature to be provided in bass range.

Another object of the present invention provides a kind of low system for electrical teaching, and the opposite side emphasis of the tonequality composition of its adjusting bass signal is with the bass performance of the sound of accurate simulation performance.

A further object of the present invention is to improve the bass drivers performance by limiting low frequency (undersonic frequency scope) displacement, thereby and relatively little loudspeaker drive is produced and the big suitable sound pressure level of loudspeaker drive.

Above-mentioned and other purpose of the present invention maybe may be that digital network reaches by a kind of simulation to signal filtering on two different bass frequencies values.Network output is regulated with gain relative to each other and can be randomly anti-phase.The output of filter network can drive single-tone circle loud speaker through the single channel power amplifier by electricity mutually, also can offer importing separately to drive each input of double-coil loudspeaker respectively of two-path amplifier.

In an exemplary embodiment, designed a kind of circuit, it has the binary channels input that is coupled to a pair of cascading filter network, utilizes inversion signal to produce the single-tone output of a pair of different frequency scope.These tone signals can electric phase adduction be applied to the single channel amplifier to single-tone circle loud speaker feed, also can offer each input channel that its output connects the power amplifier of each voice coil loudspeaker voice coil of double-coil loudspeaker.

Select intensity and the dynamics of a lower frequency range, and provide the 2nd higher frequency range to adapt to spatiality and the contributive overtone of directivity so that bass signal to be provided.These separately the signal relative level of scope can be provided with or regulate with aspect emphasizing tonequality impression or on the other hand, the various aspects of perhaps also adjustable and sound are to produce the sound that will simulate realistically.For example, this voice control system can mix (feeling in some cases) ubiquitous, direction-free ripple that the different aspect of bass signal is experienced with generation.Can launch the noticeable position of the high frequency single-tone of suitable sound level to the observer simultaneously with the identification sound source.

Meaningfully, but voice control system filtering bass signal of the present invention makes the undersonic frequency decay, to limit the imperceptible composition of the loud speaker of can overdriving.The performance of this low side restriction can the increasing range of audibility.

Like this, the mixing of various tonequality compositions limit not audible signal simultaneously, and less loud speaker has preferable performance in this voice control system control bass spectral.

Summary of drawings

Fig. 1 is the block diagram according to bass speaker circuit of the present invention.

Fig. 2 is the block diagram that the bass speaker circuit of Fig. 1 replaces output stage.

Fig. 3 be Fig. 1 the bass speaker circuit another replace the block diagram of output stage.

Fig. 4 is the curve chart of the output frequency response of the 1st dividing filter (crossover filter) circuit (being represented by dotted lines) of Fig. 1 and the 2nd dividing filter (representing with solid line).

Fig. 5 is the curve chart of the output frequency response of the 2nd dividing filter signal 27.

Fig. 6 is the curve chart of the frequency response of total loud speaker input when the 2nd dividing filter network has 1.4 gains.

Fig. 7 is the curve chart of the frequency response of total loud speaker input when the 2nd dividing filter network has 1.0 gains.

Fig. 8 is the block diagram of bass speaker circuit according to another embodiment of the present invention.

Detailed description of the present invention

Referring to Fig. 1, woofer system 10 comprises the first dividing filter network 11 with left side sound passage input 12 and right sound passage input 13.This first dividing filter network (or circuit) 11 has the attenuation slope of 200～600Hz cut-off frequency and every octave (octave) 6 to 24dB.In preferred embodiment, the first dividing filter network 11 has the attenuation slope of 250Hz cut-off frequency and every octave (octave) 24dB, dotted line in signal magnitude and the frequency curve chart is described as shown in Figure 4, this curve is for example when the signal of two passage inputs 12 and 13 equates, the response of the signal on the line 16.Notice that the cut-off frequency of 250Hz has-the 3dB response.

Produce the output signal of two sound channel passages that are used for first FL-network 11 on online 14 and be fed to first add circuit 15, can be arranged on the latter in the filter if wish.First add circuit 15 is combined into monophony (MONO) signal to left and right filtered voice signal, and warp 16 is fed to a sound channel input of the dual-channel audio amplifier 17 in the output stage 19.

From the monophonic signal of first add circuit 15 also warp 18 be fed to two passage inputs 20 and 21 of the second frequency-division filter network 22.This second frequency-division filter network 22 has the cut-off frequency that is lower than the first frequency-division filter network 11.Wherein, cut-off frequency is fixed on the last or selection betwixt of one of three preferred curve (contour).First selection provides the cut-off frequency of 50～180Hz scope and has the attenuation slope of every octave 12dB.This selection is described by the solid line of Fig. 4, and in this curve, initial filter gain is 1.4 (3dB), and the cut-off frequency that the initialize signal amplitude during from 0Hz reduces 3dB is 70Hz, the about 12dB of every octave decay.The second filter curve provides the cut-off frequency in 180～250Hz scope and has the attenuation slope of the about 18dB of every octave.The 3rd preferable selection provides the cut-off frequency of 250～400Hz scope and has the attenuation slope of about every octave 24dB.Usually, cut-off frequency falls into the centre position of these scopes, will be to higher-frequency direction inclination (slope off).Produce the filtering output signal of second each passage of frequency-division filter network on a pair of line 23 as two monophony outputs, its decay is depended on selected filter rank (order) and is (the every 6dB of every octave represents an additional pole (pole)) between every octave 6dB to 24dB.

Monophonic signal on the line 23 is fed to second add circuit 24, and the latter also can be arranged in the second frequency-division filter network 22.Second add circuit 24 is fed to inverter 26 to the monophony low frequency signal on the synthetic line 25 of the sets of signals on the line 23.26 phase places from the monophonic signal of second add circuit of inverter are anti-phase, then this signal warp 27 are fed to the input of another passage of audio frequency amplifier 17.Like this, an input warp of audio frequency amplifier 16 receives nonphase-inverting monophonic audio signal, and its cut-off frequency is higher than at another amplifier in and ends frequency from the carrying of monophonic audio signal that line 27 receives.Perhaps, a plurality of signalling channel amplifiers that separate can be handled the signal from line 16 and 27.The output 28 and 30 of audio frequency amplifier 17 is coupled to the input separately of double-tone circle woofer 31, this loud speaker by the magnetic field of inducting two signal plus.Speaker system 10 can be used more than one bass drivers or woofer.

As shown in Figure 2, can use single-tone circle woofer 50 by output stage 52 is provided alternately, in this output stage, the output signal of two-path amplifier 54 make up in second add circuit 56 with at output 58 generation monophonic signals, offers woofer.

Another kind of alternately output stage 60 illustrates in Fig. 3.In this output stage 60, line 16 and 27 contained signals before the single channel amplifier 62 that drives single-tone circle woofer 66, electricity combination in add circuit 61.

Two audio signals with crossover frequencies (one have wider frequency and another signal paraphase) are provided, it makes the bass drivers of loud speaker 31 produce an output, and this output is at the lower limit place of the range of audibility or have limited LF-response below it and have improved response in the range of audibility.Audio signal on the filter output line 27 is shown in Fig. 5 for the input 12 of system 10 and 13 amplitude response, and this curve has 3dB gain and every octave to have the complete attenuation of 36dB when 0Hz.

The amplitude of signal 16 and 27 sums is shown in Fig. 6 to the curve of frequency, with the effect of explanation native system.Speaker system response when 0Hz by audio bass circuit decay 7.7dB and all frequencies that are lower than hearing threshold value 4dB at least that decays.Speaker system 10 in 40Hz to 220Hz scope, also increased response and have at about 80Hz place peak response (+3.1dB).Native system is to be limited in the big displacement of finding in the undersonic frequency scope and to improve response more than 40Hz for the effect of bass drivers overall performance.This will allow the relatively little woofer driver of about 8 inch diameters to produce in audible frequency range and 18 inches big overall sound pressure levels that driver is suitable, and the amount of the exceeding distortion that does not have the big displacement of dimension acoustic frequency scope to cause.Can produce strong influence to the low cut that produces by the bass circuit by cut-off frequency or the gain that changes filter 11 and 22.For example, relatively the gain of the filter 22 of previous examples is become the result of gain 1 shown in Figure 7 and the result that the front is shown in Fig. 6.Notice that response is subjected to very high attenuation and influences very little in the infrasonic sound scope in the range of audibility.

In order further to understand the advantage of cascade filtering device, a simple case of native system is simulated in Laplace domain.The transfer function of filter network 11 (for example duopole low pass filter) is simulated as follows in Laplace domain: $\frac{\mathrm{OUT}1\left(S\right)}{\mathrm{IN}1\left(S\right)}=\frac{N_{11}}{(s-p_1^{11})(s-p_2^{11})}---\left(3\right)$ In the formula: OUT1 (S) is the Laplace transform of the output signal on the line 14, and IN1 (S) is the Laplace transform of the input signal on the line 12, Be the position of filter network first limit,

It is the position of second limit.Similarly, the transfer function of the second frequency-division filter network 22 can be simulated as follows in Laplace domain: $\frac{\mathrm{OUT}2\left(S\right)}{\mathrm{IN}2\left(S\right)}=\frac{N_{22}}{(s-p_1^{22})(s-p_2^{22})}---\left(4\right)$ In the formula: OUT2 (S) is the Laplace transform of the output signal on the line 23, and IN2 (S) is the Laplace transform of the input signal on the line 20,

Be the position of the second frequency-division filter network, 22 first limits, It is the position of filter network network second limit.Use algebraic manipulation and basic controlling theory, the clean transfer function y of loud speaker output can write out as follows with input 12: $\frac{y\left(s\right)}{\mathrm{IN}\left(s\right)}=\frac{N_{11}}{(s-p_1^{11})(s-p_2^{11})}-\frac{N_{22}{N}_{11}}{(s-p_1^{11})(s-p_2^{11})(s-p_1^{22})(s-p_2^{22})}---\left(5\right)$ After doing some representative calculating, can obtain following relational expression: $\frac{y\left(s\right)}{\mathrm{IN}\left(s\right)}=\frac{N_{11}(s-p_1^{22})(s-p_2^{22})-N_{22}{N}_{11}}{(s-p_1^{11})(s-p_2^{11})(s-p_1^{22})(s-p_2^{22})}---\left(6\right)$ Molecule constitutes the zero point of compound bass filtering system polynomial zero point.Are each composition of subsystem (that is N, separately these zero points ₁₁, ) majorant.Through for example Mobile and mobile cut-off frequency or for example change specific part N ₁₁Gain can be used for the dead-center position of regulating system fast and accurately, to satisfy the requirement of acoustic environment.In being shown in the above-mentioned example of Fig. 6, the value of pole location makes and places zero frequency a zero point, this explanation infrasonic sound zone utmost point low-response (being zero output at zero Hz place in theory).Regulate the specific (special) requirements that two cascaded filter are used to adapt to speaker system and audible environment remainder (for example indoor or automobile cab).

Referring to Fig. 8, another embodiment of woofer system 32 has the initial frequency-division filter network 33 that has left passage input 12 and right passage input 13.Produce the monophony output of addition on the filter network 33 online 34, it has the cut-off frequency of 60～80Hz scope and the decay of every octave 6 to 24dB, simultaneously, produce the left and right channel audio signal of a pair of gamut (being unattenuated) on online 35 and 36, parallel another frequency-division filter network 37 that is coupled to.

Adjust another filter network 37 and only make it by low frequency signal and have the selectable filter parameter identical, thereby on a pair of line 38, produce similar output signal with the second dividing filter network 22 of Fig. 1.But the signal on the line 38 is combined into monophonic signal on the line 41 by add circuit 40, presents then to negative circuit 42.Produce anti-phase monophonic signal on the negative circuit 42 online 43, it in fact only has frequency, its accurate cut-off frequency of being lower than 400Hz to depend on second filter, 37 selected parameters.

Anti-phase monophonic signal 43 is fed to a passage of amplifier 44, and this amplifier has reception another passage from the nonphase-inverting monophonic signal on the line 34 of initial frequency-division filter network 33, and this signal has the cut-off frequency of 60～80Hz scope.Two signals are amplified and be fed to electronic long amplitude of oscillation woofer (electrody namic longthrow woofer) 47 through two monophony outlet lines 45 and 46, it can be single-tone circle or double-tone circle woofer.

Two speaker systems 10 and 32 at Fig. 1 and Fig. 8 provide the separately passage of two monophonic audio input signals to amplifier, and wherein each signal has different low-frequency ranges and a signal is anti-phase with respect to another.In another embodiment, the output of two filters simulation addition, offer the single channel power amplifier and send single-tone circle woofer to.

The invention provides a kind of bass drivers circuit, its restriction infrasonic sound zone loud speaker taper vibrating diaphragm displacement.This circuit had confirmed to improve the bass response of any kind woofer (such as closed box, infinite baffle, tuning mouthful (tunedport), full loudspeaker (full horn) or isostatic type) already.But the embodiment that the present invention is not limited to narrate, these embodiment are for the present invention being described rather than being limited.

Claims (24)

1. audio speaker drive circuit that is used for bass is characterized in that this circuit comprises:

Have first input end that receives first audio signal and first filter network that produces first output of first output signal thereon, wherein, described first filter network produces described first output signal by the signal that is higher than the frequency of first cut-off frequency in described first input signal of decaying;

Have second input that receives second audio signal and second filter network that produces second output of second output signal thereon, wherein, described second filter network produces described second output signal by the signal that is higher than the frequency of second cut-off frequency in described second input signal of decaying, and described second cut-off frequency is lower than described first cut-off frequency;

Have first input end, second input terminal of described first output that is coupled to described first filter network and be connected to the audio frequency output stage of the lead-out terminal of loud speaker, described audio frequency output stage comprises the amplifier that is coupled between described first and second input terminals and lead-out terminal;

Connect, be coupled in signal inverter between described second input terminal of first filter network, first output and described audio frequency output stage with described second filter.

2. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described audio frequency output stage comprises the signal combiner that has the input that is connected to described first input end and be connected to another input of second input terminal; Described signal combiner has the output that is connected to described amplifier in.

3. audio tweeter drive circuit as claimed in claim 1, it is characterized in that, the amplifier of described audio frequency output stage is a two-path amplifier, and it has the first passage input that is connected to described first input end, the second channel input that is connected to described second input terminal and the 1st and the 2nd channel output end.

4. audio tweeter drive circuit as claimed in claim 3 is characterized in that, further comprises having a voice coil loudspeaker voice coil that is coupled to described first passage output and the double-coil loudspeaker that is coupled to another voice coil loudspeaker voice coil of described second channel output.

5. audio tweeter drive circuit as claimed in claim 3, it is characterized in that, described audio frequency output stage further comprises having an input that is connected to described first passage output and the signal combiner that is connected to another input of described second channel output, and described signal combiner has the output that is connected to described lead-out terminal.

6. audio tweeter drive circuit as claimed in claim 5 is characterized in that, further comprises the single-tone circle loud speaker of the described lead-out terminal that is coupled to described audio frequency output stage.

7. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described first cut-off frequency is positioned at 200Hz to 600Hz scope.

8. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described first cut-off frequency is positioned at 200Hz to 600Hz scope and described first filter network has every in fact octave 12dB decay.

9. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described second cut-off frequency is positioned at 50Hz to 400Hz scope.

10. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described second cut-off frequency is positioned at 50Hz to 180Hz scope and described second filter network has every in fact octave 12dB decay.

11. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described second cut-off frequency is positioned at 180Hz to 250Hz scope and described second filter network has every in fact octave 18dB decay.

12. audio tweeter drive circuit as claimed in claim 1 is characterized in that, described second cut-off frequency is positioned at 250Hz to 400Hz scope and described second filter network has every in fact octave 18dB decay.

13. an audio tweeter drive circuit that is used for the bass frequency range is characterized in that this circuit comprises:

Have first pair of input of a pair of audio signal of reception and first filter network of first pair of output, wherein, described first filter network is decayed and is higher than the frequency signal of first cut-off frequency in the described a pair of audio signal, produces a pair of filtering signal at described first pair of output;

Have the input that is connected to described first pair of output and first add circuit of output, on this output, produce monophonic signal by making up described a pair of signal through filtering;

Be connected to described add circuit output and have second filter network of output, wherein, the decay of described second filter network is higher than the signal of second cut-off frequency and produces signal through filtering at the output of described second filter network in the signal that described first add circuit receives, described second cut-off frequency is lower than described first cut-off frequency;

Be connected to the output of second filter network and have the signal inverter of an output;

Have the output that is coupled to described adder circuit first input end, be coupled to second input terminal of described signal inverter output and be connected to the audio frequency output stage of the lead-out terminal of loud speaker, described audio frequency output stage comprises the amplifier that is coupled between first, second input terminal and the lead-out terminal.

14. audio tweeter drive circuit as claimed in claim 13, it is characterized in that, described audio frequency output stage comprises having an input that is connected to described first input end and second add circuit that connects another input of described second input terminal, and described second add circuit has the output that is connected to described amplifier in.

15. audio tweeter drive circuit as claimed in claim 13, it is characterized in that, the amplifier of described audio frequency output stage is a two-path amplifier, and it has a passage input that is connected to described first input end, the second channel input that is connected to described second input terminal and first and second channel output ends.

16. audio tweeter drive circuit as claimed in claim 15 is characterized in that, this circuit further comprises having a voice coil loudspeaker voice coil that is coupled to described first passage output and the double-coil loudspeaker that is coupled to another voice coil loudspeaker voice coil of described second channel output.

17. audio tweeter drive circuit as claimed in claim 15, it is characterized in that, described audio frequency output stage further comprises having an input that is connected to described first passage output and second add circuit that is connected to another input of described second channel output, and described second add circuit has the output that is connected to described lead-out terminal.

18.. audio tweeter drive circuit as claimed in claim 13 is characterized in that, described first cut-off frequency is positioned at 200Hz to 600Hz scope.

19. audio tweeter drive circuit as claimed in claim 13 is characterized in that, ends frequency and is positioned at 50Hz to 400Hz scope in described second year.

20. audio tweeter drive circuit as claimed in claim 13, it is characterized in that the characteristic of described second filter network is selected from the group of being made up of following parameter: second cut-off frequency is positioned at 50Hz to 180Hz scope and decay comes down to every octave 12dB, second cut-off frequency is positioned at 180Hz to 250Hz scope and decay comes down to every octave 18dB, second cut-off frequency is positioned at 250Hz to 400Hz scope and decay comes down to every octave 18dB.

21. the audio tweeter drive circuit of a bass scope is characterized in that, this circuit comprises:

First filter network with first pair of input of output and a pair of audio signal of reception, wherein, described first filter network produces monophonic signal at output, and this monophonic signal is the combination that is lower than the signal of first cut-off frequency in the described a pair of audio signal;

Second filter network with first pair of input of two outputs and the described a pair of audio signal of reception, wherein, described second filter network decay the frequency that is higher than second cut-off frequency in the described a pair of audio signal signal and on two outputs, produce a pair of signal through filtering, described second cut-off frequency is higher than described first cut-off frequency;

Have the input of two outputs that are connected to described second filter and first add circuit of output, on this output, produce monophonic signal by the signal that makes up from described second filter network;

The anti-phase described first add circuit output end signal also has the signal inverter of an output;

Have the output that is coupled to described first filter network first input end, be connected to second input terminal of described signal inverter output and be connected to the audio frequency output stage of the lead-out terminal of loud speaker, described audio frequency output stage comprises the amplifier that is coupled between described first, second input terminal and the lead-out terminal.

22. audio tweeter drive circuit as claimed in claim 21 is characterized in that, described first cut-off frequency is positioned at the decay that 60Hz to 80H scope and described first filter network have every in fact octave 6 to 24dB.

23. audio tweeter drive circuit as claimed in claim 21 is characterized in that, described second cut-off frequency is positioned at 50Hz to 400Hz scope.

24. audio tweeter drive circuit as claimed in claim 21, it is characterized in that the characteristic of described second filter network is selected from the group of being made up of following parameters: second cut-off frequency is positioned at 50Hz to 180Hz scope and decay comes down to every octave 12dB, second cut-off frequency is positioned at 180Hz to 250Hz scope and decay comes down to every octave 18dB, second cut-off frequency is positioned at 250Hz to 400Hz scope and decay comes down to every octave 18dB.

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