CN110740403B

CN110740403B - Signal processing device for line array loudspeaker system and line array loudspeaker system

Info

Publication number: CN110740403B
Application number: CN201911020302.4A
Authority: CN
Inventors: 葛虎; 于娟
Original assignee: Shanghai Yeahoo Acoustic Technology Co ltd
Current assignee: Shanghai Yeahoo Acoustic Technology Co ltd
Priority date: 2019-10-24
Filing date: 2019-10-24
Publication date: 2021-02-09
Anticipated expiration: 2039-10-24
Also published as: CN110740403A

Abstract

The invention discloses a signal processing device for a line array loudspeaker system and the line array loudspeaker system, wherein the signal processing device comprises a plurality of groups of analog active or passive signal processing channels which comprise one or more of an equalization function, a filtering function, a time delay function and a gain adjustment function, wherein the equalization function is used for locally increasing or reducing the gain of certain frequency bands in the whole passband; the filtering function is used for processing at least one of low-pass filtering, high-pass filtering, band-stop filtering or all-pass filtering on the signals of the whole passband, so that the amplitude, the phase and the time delay of the signals of the passband are changed according to the filtering rule; the delay function is used for delaying a certain section or all of the signals of the whole passband; the gain adjustment function is used to proportionally increase or decrease the amplitude of the signal across the passband.

Description

Signal processing device for line array loudspeaker system and line array loudspeaker system

Technical Field

The invention belongs to the technical field of electroacoustic, and particularly relates to a signal processing device for a line array loudspeaker system and the line array loudspeaker system.

Background

The linear array loudspeaker system has the advantages of strong vertical directivity, wide coverage range and the like. And the sound pressure fluctuation caused by the change of the transmission distance is smaller than that of the traditional loudspeaker. The method can be used under the conditions that standing wave interference needs to be avoided, a long transmission distance is needed, and the acoustic environment is complex. Typical usage scenarios are as follows: low sound pressure applications, video surveillance, exclusive shops, passenger centers, sound reinforcement applications, conference rooms, classrooms, style buildings, and the like. The existing line array loudspeaker system mostly adopts a passive compensation network composed of passive power devices (such as resistors, inductors and capacitors) or an expensive DSP digital signal processing system.

Disclosure of Invention

In view of the above technical problems, the present invention is directed to providing a signal processing device for a line array speaker system and a line array speaker system.

In order to solve the technical problems, the invention adopts the following technical scheme:

a signal processing apparatus for a line array loudspeaker system, comprising a plurality of sets of analogue active or passive signal processing channels including one or more of an equalisation function, a filtering function, a delay function, a gain adjustment function, wherein the equalisation function is used to locally boost or reduce the gain of certain frequency bands of an overall passband; the filtering function is used for processing at least one of low-pass filtering, high-pass filtering, band-stop filtering or all-pass filtering on the signals of the whole passband, so that the amplitude, the phase and the time delay of the signals of the passband are changed according to the filtering rule; the delay function is used for delaying a certain section or all of the signals of the whole passband; the gain adjustment function is used to proportionally increase or decrease the amplitude of the signal across the passband.

Preferably, the total number of channels n.gtoreq.3.

Preferably, the center frequency of an equalizing point of the equalizing function is any frequency between 20KHz and 20KHz, the number of adjustable frequency bands is 0 to 10, the quality factor (Q value) is any value between 0.1 and 20, and the center frequency voltage gain of the equalizing module is any value between-20 dB and +20 dB.

Preferably, the type of the filtering function comprises any one of high pass, low pass, band stop, full pass and delay, the working frequency range of the filter is any frequency range between 20KHz and 20KHz, the pass band gain of the filter is any value between-40 dB to +40dB, and the out-of-band attenuation of the filter is any value between +20dB to-120 dB/dec. Where the positive sign indicates gain boost and the negative sign indicates gain attenuation.

Preferably, the working frequency range of the delay function is any frequency range between 20KHz and 20KHz, and the delay value is any value between 0mS and 200 mS.

Preferably, the gain of the gain adjusting function is any value between-120 and +120dB, wherein the negative sign represents the input and output in phase opposition, and the positive sign represents the input and output in phase opposition.

A line array loudspeaker system comprises the signal processing device for the line array loudspeaker system, wherein input signals of the system are analog audio electric signals for playing, the audio signals are divided into a plurality of paths and input into the signal processing devices which work independently and are used for the line array loudspeaker system, the signals are correspondingly processed, the processed audio electric signals are subjected to voltage amplification and impedance conversion through power amplifiers of all groups and finally become audio signals with high voltage and low internal resistance, the audio signals are used for driving loudspeaker units of all groups, and the loudspeaker units of all groups emit sound.

Drawings

Fig. 1 is a schematic structural diagram of a signal processing apparatus for a line array loudspeaker system according to an embodiment of the present invention;

figure 2 is a functional block diagram of a line array loudspeaker system according to an embodiment of the invention;

FIG. 3 is a schematic diagram of a signal processing unit of a line array loudspeaker according to an embodiment of the invention;

figure 4 is a schematic view of the directional deflection of a line array loudspeaker system according to an embodiment of the invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the signal processing apparatus for a line array speaker system according to an embodiment of the present invention is an active or passive signal processing apparatus including a plurality of sets of analog circuits, and includes one or more signal processing units having an equalization function, a filtering function, a delay function, a gain adjustment function, and the like. The combination sequence and combination mode are arbitrary, and some modules can be deleted.

In the device, the loudspeaker system needs array work, so the total channel number n of the device is more than or equal to 3.

It should be noted that each module listed in fig. 1 is a distinction standing on the function of signal processing, and does not mean that each unit circuit must be physically present. In particular, the equalization function is used to locally raise or lower the gain of certain bands in the entire pass band; the filtering function is used for processing low-pass filtering, high-pass filtering, band-stop filtering and all-pass filtering on the signals of the whole passband, so that the amplitude, the phase, the time delay and the like of the signals of the passband are changed according to the filtering rule; the delay function is used for delaying a certain section or all of the signals of the whole passband; the gain adjustment function is to proportionally increase or decrease the amplitude of the signal across the passband. In physical circuits, some unit circuits are often designed to have the above functions at the same time. For example, when a filter is designed, the filter may bring a phase shift besides attenuation of an out-of-band frequency response, and if the phase shift just meets the delay requirement of a certain frequency band, the function of the filter can be directly utilized without additionally designing a delay circuit. Still alternatively, all-pass filtering is often classified as a filter, but it can perform well with a delay function.

In summary, in the present apparatus, the functions mentioned in each channel are named according to their roles in signal processing, and there is no specific combination and order. And various functions related to the channels can be deleted and simplified. For example, one or more of the functions, such as equalization, filtering, and delay, may be removed, and only one or more of the functions, such as gain adjustment, may be retained; or one or more functions of equalization, filtering, time delay and gain adjustment are realized by one unit circuit; or one or more channels (but not all channels) are not processed and are directly communicated; or a certain module circuit is used for multiple times, for example, 2 filter modules are connected in series to form an enhanced filter module circuit; or a mixing module is adopted, and the mixing module has the signal processing functions of the modules, such as filtering and gain adjusting functions are combined into a filtering module circuit with gain adjustment; or the circuit of a certain module is deformed to have the functions of other modules, for example, devices such as inductors and the like are added on the basis of a filter circuit to realize the double functions of filtering and balancing; or a combination of the above possibilities. The above processing methods are all reasonable variations under the patent guidance, and all fall under the protection of the patent.

To detail the relationship between the electrical parameters of the individual channel modules, the channel corresponding to the group of loudspeaker units located at a certain position of the line array loudspeaker system is called channel 1, the channel corresponding to the group of loudspeaker units immediately adjacent to this position is called channel 2, and so on … up to channel n. In the case of a symmetric line array loudspeaker system, the channel 1 is generally located in the centre of the line array loudspeaker unit combination; in the case of an asymmetric line array loudspeaker system, the channel 1 may be located at any one of the line array loudspeaker units, and in this case, the channel 2 … to the channel n may be defined in two directions away from the channel 1 with this unit as the channel 1. In an asymmetric line array loudspeaker system the presence of such a channel 1 must be found.

The electrical parameter relationship of each channel module is as follows: if the electrical parameter characteristic of channel 1 is referenced, then within a certain frequency band in the range of 20Hz-20KHz, the relationship between the electrical parameters of channels 2 to n is: a time-lapse, gradually increasing trend or gradually decreasing trend; frequency response, the tendency of the high frequency part of the channel away from channel 1 decreases. In practical application, sometimes based on the vertical directivity and sound field control requirements, the gains of the high-frequency parts of 1-2 groups of loudspeakers (channel 2 and channel 3) near the channel 1 are slightly increased or kept unchanged, but the fluctuation range of the gains is generally within the +6dB voltage gain range, and the frequency response of the channel far away from the channel 1 still has the tendency of high-frequency reduction in overall view; the gain, the tendency for the channel gain away from channel 1 to decrease or remain constant. The gradual increase or gradual decrease of the time delay is to expand or reduce the vertical directivity of the sound column; the gradual reduction of the high-frequency response is to improve the high-frequency response, and meanwhile, the reduction of the high-frequency gain also reduces the directional side lobe at high frequency; the gain reduction is also to reduce the directional side lobe, considering that the frequency response part aims at the reduction of the high-frequency gain, if the design only needs to reduce the side lobe of the high frequency, because the high frequency of the frequency response has gradual attenuation, the variation trend of the gain can also be kept unchanged. The electrical principle of the signal processor of the present embodiment is illustrated by taking four channels as an example. Referring to fig. 3, it can be seen that the channel 1 is a simple voltage follower, and the equalization, filtering, delay and gain of the input signal are not processed. Channel 1 is also referenced as an electrical parameter of the entire signal processing module. Compared with the channel 1, the channel 2 is subjected to equalization, filtering and delay processing, and an inductor is added to a feedback loop to improve the frequency response of a high-frequency band. At the frequency band being processed, channel 2 may have a slight increase in high frequency gain compared to channel 1, but the fluctuation range is controlled to be within +6dB of voltage gain. The filtering and delay functions in the signal processing units are combined because the signal is subjected to phase shift or delay after being filtered. And compared with the channel 1, the channel 3 is subjected to filtering and delay processing. And compared with the channel 1, the channel 4 is subjected to filtering and delay processing. The high frequency gain is reduced for channels 3, 4 compared to channel 1. Since the channels 2 to 4 are basic circuit architectures of filtering and filtering plus delay, the gain after filtering is also different in the audio frequency band to be processed. In summary, from channel 1 to channel 4, the delay gradually increases in the audio frequency band to be processed, and in terms of the high frequency response, the high frequency response of the channel far from channel 1 is reduced, and the in-band gain of the channel far from channel 1 is constant or reduced.

It should be noted that the above-mentioned "constant" includes the fluctuation of normal circuit parameters and the variation of a small range in the signal frequency band to be processed, and generally speaking, the fluctuation and the small range variation correspond to the voltage gain fluctuation range of ± 6 dB.

In this embodiment, the phases of the channels 3 and 4 are reversed by 180 ° compared with the phases of the

channels

1 and 2, and in this case, the phases can be adjusted by adding an inverter circuit, or the phases can be directly coupled in reverse when the power amplifier outputs to the speaker unit. In the foregoing variation law of gain, phase, etc., this has been taken into consideration.

In the present arrangement, the circuitry involved in each channel may be different depending on the requirements of the line array loudspeaker system.

Typical parameter ranges for the various functional units of the device are listed below.

And (3) an equalizing function: center frequency of an equalization point: any frequency between 20-20 KHz; the equalizer may adjust the number of frequency bands: 0 to 10; equalizer quality factor (Q value): any value between 0.1 and 20; equalizer center frequency voltage gain: any value between-20 and +20 dB.

And (3) a filtering function: the working frequency range is as follows: any frequency band between 20 and 20 KHz; pass band gain: any value between-40 and +40 dB; out-of-band attenuation: any value between +20 and-120 dB/dec, wherein a positive sign indicates gain boost and a negative sign indicates gain attenuation.

The time delay function is as follows: the working frequency range is as follows: any frequency band between 20 and 20 KHz; delay value: any value between 0 and 200 mS.

The gain adjustment function: gain: any value between-120 and +120dB, wherein the negative sign represents the inverted input and output, and the positive sign represents the in-phase input and output.

In summary, as long as the signal processing device for the line array speaker system is designed based on the analog circuit architecture, the total number of channels of the signal processing device is greater than or equal to 3, and each channel of the signal processing device has one or more functions of the above-mentioned equalization, filtering, delay, and gain control (as a special case, there may be a case where some but not all channels are directly connected), and meets the typical parameter range of each module, and when the signal processing device is used in the signal processing occasion of the line array speaker system, the characteristics of the device are met, and the device is protected by the patent.

On the basis of fig. 1, referring to fig. 2, an embodiment of the present invention provides a line array speaker system, where an input signal of the system is an analog audio electrical signal for playing, the audio signal is divided into a plurality of paths, and is input to a plurality of paths of signal processing system devices for the line array speaker system, which operate independently, and performs corresponding processing on the signal, and the processed audio electrical signal is subjected to voltage amplification and impedance conversion by each group of power amplifiers, and finally becomes an audio signal with high voltage and low internal resistance, which is used for driving each group of speaker units, and the speaker units of each group make sound.

The working principle of the signal processing device is explained from the aspects of aiming at the principle and the performance improvement of the line array loudspeaker system, and the like:

(1) improving beam direction

By giving different delay treatments to the different loudspeaker units making up the line array loudspeaker system, deflection of the beam can be achieved effectively. Fig. 4 is a simple illustration of the principle of achieving a beam deflection by a fixed angle. In this illustration, the delay module generates different delays t, 2t, · (n-1) t, with a loudspeaker unit pitch of L and a sound velocity of c. It can be seen from the schematic that different delays of the speaker units will result in different spatial positions of arrival of the same sound wave at the same time, and this will form the wave front as indicated by the thick black line in fig. 4.

In fig. 4, α is a deflection angle, and it can be seen that the formation of the deflection angle is determined by both the physical position of the speaker unit and the delay amount of the speaker unit. In the example of fig. 4, the deflection angle d can be expressed as:

where t is the delay time, c is the sound velocity, and L is the spacing between the speaker units.

(2) Improved side lobe

Theoretical studies have shown that if the phases of vibrations are the same between the loudspeaker units making up the line array, but the intensity of the vibrations varies linearly from a given value in the center to 0 at both ends, the loudspeaker array may have the opportunity to be equivalent to a wedge line source, characterized by: the side lobe is smallest on the directional diagram. In line array loudspeaker system applications, it is also desirable to minimize side lobes to avoid unwanted reflections and the like. At this time, the equalization, filtering and gain control unit in the signal processing device of the line array loudspeaker can be used for conveniently realizing the nearly ideal directivity characteristic.

(3) Improving high frequency response

When a plurality of speaker units are combined into a speaker array, high frequencies are superimposed or attenuated at certain distances and at certain frequencies. This is because the high frequency sound wave has a short wavelength, and the sound waves output by the two end speakers and the middle speaker have a superposition effect or an attenuation effect at a specific distance and a specific frequency. This results in unevenness of the high frequency response. This unevenness in frequency response affects the use effect.

In practice, when the signal processing apparatus of the line array loudspeaker system is applied, the equalization and filtering functions in the line array loudspeaker signal processing apparatus are often used to appropriately attenuate the high frequency of the loudspeaker units at both ends of the array. In this case, the influence of this effect can be effectively reduced.

(4) Improving speech intelligibility and suppressing acoustic feedback

Through the setting and optimization, the directivity and the performance of the line array loudspeaker system are effectively improved. On the application level, the energy of the beam is concentrated, and the energy of the direct sound is increased, so that the effective reverberation time can be reduced. Therefore, the speech definition can be improved by using the system in the hall. Meanwhile, due to the optimization of the directivity of the line array loudspeaker system, when the line array loudspeaker system is applied, a sound pickup is arranged at a position outside the directional beam of the line array loudspeaker system, so that the acoustic feedback can be effectively inhibited.

It is to be understood that the exemplary embodiments described herein are illustrative and not restrictive. Although one or more embodiments of the present invention have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

1. A signal processing apparatus for a line array loudspeaker system comprising a plurality of sets of analogue signal processing channels, active or passive, and containing one or more of equalisation, filtering, delay, gain adjustment functions, wherein the equalisation functions are used to locally boost or reduce the gain of some of the whole passband; the filtering function is used for processing at least one of low-pass filtering, high-pass filtering, band-stop filtering or all-pass filtering on the signals of the whole passband, so that the amplitude, the phase and the time delay of the signals of the passband are changed according to the filtering rule; the delay function is used for delaying a certain section or all of the signals of the whole passband; the gain adjustment function is used to proportionally boost or reduce the amplitude of the signal across the passband,

the total channel number n is more than or equal to 3, the electrical parameter characteristic of the channel 1 is taken as a reference in a certain frequency band within the range of 20Hz-20KHz, and the relationship between the electrical parameters of the channels from 2 to n is as follows: a time-lapse, gradually increasing trend or gradually decreasing trend; frequency response, the tendency of the high frequency part of the channel away from channel 1 to decrease,

the center frequency of an equalizing point of the equalizing function is any frequency between 20KHz and 20KHz, the number of adjustable frequency bands is 0-10, the quality factor is any value between 0.1 and 20, the gain of the center frequency voltage is any value between-20 dB and +20dB, the types of the filtering functions comprise any one or combination of a high pass, a low pass, a band stop, a full pass and a delay, the working frequency band range is any frequency band between 20KHz and 20KHz, the gain of the band pass is any value between-40 dB and +40dB, the out-of-band attenuation is any value between +20dB to-120 dB/dec, wherein a positive sign represents gain increase, a negative sign represents gain attenuation, the working frequency band range of the delay function is any frequency band between 20KHz and 20KHz, the delay value is any value between 0ms and 200ms, and the gain adjusting range of the gain adjusting function is any value between-120 dB and +120dB, the negative sign represents the input-output inverted phase, and the positive sign represents the input-output in-phase.

2. A line array loudspeaker system, comprising the signal processing device for line array loudspeaker system as claimed in claim 1, wherein the input signal of the system is analog audio electric signal for playing, the analog audio electric signal is divided into a plurality of paths, and is input to a plurality of paths of signal processing devices for line array loudspeaker system which work independently, the signal is processed correspondingly, the processed audio electric signal is processed by each group of power amplifiers, and is subjected to voltage amplification and impedance conversion, and finally becomes an audio signal with high voltage and low internal resistance, which is used for driving each group of loudspeaker units to make sound.