CN108462921B - Loudspeaker sound field equalizing equipment - Google Patents
Loudspeaker sound field equalizing equipment Download PDFInfo
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- CN108462921B CN108462921B CN201710089370.0A CN201710089370A CN108462921B CN 108462921 B CN108462921 B CN 108462921B CN 201710089370 A CN201710089370 A CN 201710089370A CN 108462921 B CN108462921 B CN 108462921B
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- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R3/00—Circuits for transducers, loudspeakers or microphones
- H04R3/04—Circuits for transducers, loudspeakers or microphones for correcting frequency response
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
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Abstract
The invention relates to the technical field of audio signal processing, and discloses a loudspeaker sound field equalization device which comprises a collecting device, a sound source processing device and a control device, wherein the collecting device is used for collecting the output of a sound source; the sound source fitting device is used for generating a fitting frequency response characteristic curve for a sound source; the processor is used for generating a response frequency response characteristic curve according to the output of the sound source collected by the collecting device, comparing the difference between the fitted frequency response characteristic curve and the response frequency response characteristic curve, and setting an equalizing filter of a corresponding grade according to the difference and different frequency bands; the equalization filter is used for filtering the output of the sound source at a corresponding level and outputting the filtered sound source through a loudspeaker; the collecting device collects the output of the filtered sound source through the loudspeaker, the adjusted response frequency response characteristic curve is generated by the processor, the response frequency response characteristic curve is compared with the fitting frequency response characteristic curve, filtering is repeatedly carried out until the response frequency response characteristic curve is consistent with the fitting frequency response characteristic curve, the sound source is adjusted according to different fitting curves to output different scene effects, the adjusting process is automatically completed, and the working efficiency and the precision are improved.
Description
Technical Field
The invention relates to the technical field of audio signal processing, in particular to loudspeaker sound field equalization equipment.
Background
Under the application backgrounds of KTV, concert halls and the like, after new engineering construction is completed, audio curves in rooms need to be adjusted, or after the KTV and the concert halls operate for a period of time, the arrangement of furniture in the rooms and the aging of decoration materials can affect the audio curves in the rooms. It is necessary to hire professional disc-jockets to make adjustments to the audio equipment/speakers in various rooms of the KTV or concert hall.
And (4) adjusting the balance curve through the effect device at the optimal high-pitch position by a disc-jockey according to experience. And the sound tuner repeatedly compares the played music in the adjusting process to achieve the optimal sound tuning effect.
Manual tuning has many limitations, such as poor accuracy, long adjustment time, uneven horizontal level of disc-jockey, high cost, etc.
Disclosure of Invention
The invention aims to provide loudspeaker sound field equalization equipment which automatically performs sound field equalization based on sound equipment/loudspeakers in application occasions such as KTV and concert halls, can set equalization matching curves in different shapes and realizes automatic fitting of room frequency response curves. In the automatic equalization process, a pink noise generator is utilized, audio data are received through a testing microphone to be analyzed and processed, equalization curve fitting is carried out according to the difference between a room frequency response characteristic curve and a fitting curve, equalized pink noise is output, and fitting of the room frequency response curve is completed through multiple feedback. Four-level precision fitting is adopted, and curve fitting is efficiently realized from coarse to fine. The method has the advantages that the rapid automatic balance is realized for the rooms, the room curve adjustment precision can be controlled within 1dB, the adjustment time is controlled within 140 seconds, the tuning cost and time are greatly saved, the adjustment precision is high, different fitting frequency response characteristic curves are set for different rooms, and the room frequency response curves of corresponding styles are matched for different room styles.
In order to achieve the above object, the present invention provides a speaker sound field equalizing apparatus comprising: a collecting device for collecting the output of the sound source; the sound source fitting device is used for generating a fitting frequency response characteristic curve for a sound source; the processor is used for generating a response frequency response characteristic curve according to the output of the sound source collected by the collecting device, comparing the difference between the fitted frequency response characteristic curve and the response frequency response characteristic curve, and setting an equalizing filter with a corresponding grade according to the difference and different frequency bands; the equalization filter is used for filtering the output of the sound source at a corresponding level and outputting the filtered sound source through a loudspeaker; the acquisition device is further configured to: the system is used for collecting the output of the sound source filtered by the equalizing filter through a loudspeaker; and the processor is further configured to: generating an adjusted response frequency response characteristic curve according to the sound source which is acquired by the acquisition device and filtered by the equalizing filter and output by a loudspeaker, comparing the adjusted response frequency response characteristic curve with the fitting frequency response characteristic curve, and performing filtering of the next level according to the comparison difference so that the adjusted response frequency response characteristic curve is consistent with the fitting frequency response characteristic curve, wherein the equalizing filters of different levels set different transfer function parameters.
Preferably, the filters are arranged into four stages, and the number of the filters in each stage is several; the four levels of filters are sequentially configured to: for: adjusting high frequency, adjusting the high frequency part of the response frequency response characteristic curve; roughly adjusting envelope, and adjusting the signal which is farthest from the fitted frequency response curve; fine adjustment, adjusting the signal with the frequency within the range of 3 dB; and fine adjustment, namely adjusting the signal with the frequency within the range of 1 dB.
Preferably, the processor generating the response frequency response characteristic curve according to the output of the loudspeaker comprises: and after sound sources output by a loudspeaker are collected and enter the processor, the processor performs discrete Fourier transform to generate an amplitude-frequency curve, and the amplitude-frequency curve is subjected to transverse and longitudinal smoothing to obtain a frequency response curve of a room to serve as the response frequency response characteristic curve.
Preferably, the processor comparing the difference between the fitted frequency response characteristic curve and the response frequency response characteristic curve comprises: averaging all points of the fitted frequency response characteristic curve to obtain a fitted average level value; averaging the response frequency response characteristic curve to obtain an initial average level value; the difference of the fitted average level value and the initial average level value is calculated.
Preferably, the number of cycles of filtering of said filter of each level is greater than 1, the non-first filtering being dependent on the result of the previous filtering.
Preferably, the filter is a second-order equalization filter, and the boost level boost (n) of the second-order equalization filter is set to be (boost (n-1) + (frequency point level corresponding to a fitted frequency response curve-center frequency point level)). the automatic equalization adjustment scale factor; the automatic equalization adjustment scale factor is obtained by the following method: and setting the automatic equalization lowest level of a second-order equalization filter, wherein the automatic equalization adjustment scale factor is the ratio of the initial average level value to the automatic equalization lowest level.
Preferably, the parameter setting for the high-frequency part of the adjustment response frequency response characteristic curve comprises: the central frequency point f0 is 16kHz and Q is 0.5 central frequency point/(central frequency point — bandwidth level corresponding frequency point).
Preferably, the parameter setting for coarse tuning further comprises setting: the central frequency point f0 is the frequency point farthest from the fitted frequency response characteristic curve in the current curve, and Q is 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
Preferably, when boost (n) exceeds the maximum level of the second order equalization filter, boost (n) is set to the maximum level of the second order equalization filter.
Preferably, the parameter setting for fine tuning further comprises: the central frequency point f0 is set to be the frequency point farthest from the fitted curve in the current curve, and Q is set to be 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
Preferably, the setting of the parameters for fine tuning further comprises: the central frequency point f0 is set to be the frequency point farthest from the fitted curve in the current curve, and Q is set to be 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
Through above-mentioned technical scheme, the treater produces the pink noise signal, plays the pink noise through controlling main audio amplifier, gathers the room initial amplitude-frequency curve through testing the microphone and comes in. And the processor analyzes the acquired initial amplitude-frequency curve and compares the acquired initial amplitude-frequency curve with the amplitude-frequency curve to be fitted. And determining the reference levels of the two curves to enable the average levels of the two curves to be the same value, and starting automatic equalization, wherein in the process, the processor adjusts parameters such as frequency points, Q values, gains and the like of the equalizer by comparing the reference amplitude-frequency curve with the acquired amplitude-frequency curve, so that the equalizer acts on an output end. And the whole automatic equalization is completed by repeatedly comparing, acquiring and adjusting for many times. The data is smoothed in the horizontal and vertical directions when the collected audio data is analyzed.
When the adjustment is carried out for multiple times, a multi-section equalization hierarchical adjustment strategy is adopted, the adjustment is divided into four grades, and each grade is allocated with a specific number of equalization filters. The first grade mainly adjusts the high-frequency part of the curve so as to solve the problem of high-frequency deficiency of a KTV room above 16K; the second level is mainly to roughly adjust the large envelope, so that the room curve fitting accuracy is controlled within 5 dB. The fitting precision of the third-level adjusting curve is within 3 dB; the fourth level is mainly curve fine tuning, and the room curve fitting accuracy can be controlled within 1 dB. In the adjustment process, the unevenness of the medium and low frequencies in the KTV environment is poor, so that at most 5 equalization filters are allocated to the frequency band above 6K in the equalization process, and the rest 17 filters are all used for adjusting the frequency response curve below 6K.
And after all adjustments are completed, the adjusted curves are collected again and compared with the reference curve. The fitness reaching the specified standard is one-time automatic equalization success.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic structural diagram of a loudspeaker sound field equalization apparatus according to an embodiment of the present invention;
fig. 2 is a flowchart for sound field equalization using a speaker sound field equalizing apparatus according to an embodiment of the present invention;
fig. 3 is a flowchart of sound field equalization high frequency adjustment using the speaker sound field equalization apparatus of an embodiment of the present invention;
fig. 4 is a flowchart for determining the adjustment result of sound field equalization using the speaker sound field equalizing apparatus according to the embodiment of the present invention.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Fig. 1 is a schematic structural diagram of a loudspeaker sound field equalization apparatus according to an embodiment of the present invention. A speaker sound field equalizing apparatus according to an embodiment of the present invention as shown in fig. 1 includes: a collecting device 40 for collecting the output of the sound source 10; a sound source fitting device 30 for generating a fitted frequency response characteristic curve for a sound source 10;
a processor 50, configured to generate a response frequency response characteristic curve according to the output of the sound source 10 collected by the collection device 40, compare the difference between the fitted frequency response characteristic curve and the response frequency response characteristic curve, and set an equalization filter 60 of a corresponding grade according to the difference and different frequency bands; an equalization filter 60 for filtering the output of the sound source 10 by a corresponding level and outputting the filtered sound source through a speaker 20; the acquisition device 40 is further configured to: to collect the output of the sound source 10 filtered by the equalization filter 60 through the loudspeaker 20; and the processor 50 is further configured to: generating an adjusted response frequency response characteristic curve according to the output of the sound source 10, which is acquired by the acquisition device 40 and filtered by the equalization filter 60, through the loudspeaker 20, comparing the adjusted response frequency response characteristic curve with the fitted frequency response characteristic curve, and performing filtering of the next level according to the comparison difference so that the adjusted response frequency response characteristic curve is consistent with the fitted frequency response characteristic curve, wherein the equalization filters 60 of different levels set different transfer function parameters.
And when the adjusted response frequency response characteristic curve is consistent with the fitted frequency response characteristic curve, outputting the adjusted sound source through the loudspeaker 20.
In the above solution, the sound source 10 may be pink noise generated by a processor, and may be generated by prerecorded data playing, or may be generated by the following formula:
b0＝0.999*b0+0.056*random；
b1＝0.993*b1+0.075*random；
b2＝0.969*b2+0.153*random；
b3＝0.866*b3+0.310*random；
b4＝0.550*b4+0.533*random；
b5＝-0.762*b5-0.017*random；
b6＝0.116*random；
out＝b0+b1+b2+b3+b4+b5+b6+0.536*random；
wherein random is a random number sequence, and out is the output pink noise.
According to one embodiment of the present invention, the equalization filters 60 are arranged in four stages, and the number of the equalization filters in each stage is several; the four levels of filters are sequentially configured to: for: adjusting high frequency, adjusting the high frequency part of the response frequency response characteristic curve; roughly adjusting envelope, and adjusting the signal which is farthest from the fitted frequency response curve; fine adjustment, adjusting the signal with the frequency within the range of 3 dB; and fine adjustment, namely adjusting the signal with the frequency within the range of 1 dB.
According to one embodiment of the present invention, the processor 50 generating the response characteristic curve according to the output of the speaker 20 includes: after a sound source 10 output by a loudspeaker 20 is collected and enters the processor, the processor 50 performs discrete Fourier transform to generate an amplitude-frequency curve, and the amplitude-frequency curve is subjected to transverse and longitudinal smoothing to obtain a frequency response curve of a room, so as to be used as the response frequency response characteristic curve.
After the audio data collected by the ADC enters the processor 50, the processor 50 first performs 1024-point discrete fourier transform to generate a 512-point amplitude-frequency curve. And then, performing horizontal and longitudinal smoothing on the amplitude-frequency curve generated by continuous acquisition to obtain a frequency response curve of the room. Averaging the points of the frequency response curve yields the average level value of the room.
The longitudinal N-order smoothing refers to point-to-point averaging of N512-point amplitude-frequency curve arrays. For example, there are three sets of 512-point amplitude-frequency curve data A, B, C, which are respectively a0-a511, b0-b511, and c0-c511, and the three sets are averaged point-to-point to generate the array D, D0-D511. The generation method is d0 ═ (a0+ b0+ c0)/N, where N ═ 3. d1-d511 were calculated in the same manner as above.
The transverse M-L step smoothing process is to perform L times of average value processing between adjacent M points on an amplitude-frequency curve with 512 points. For example, a 512-point amplitude-frequency curve array D, and the data are D0-D511. And performing transverse smoothing processing on the data with M-4 and L-2 points. Resulting in array E, data E0-E511.
The calculation method comprises the following steps:
e0＝(d0+d1+d2+d3)/4，
e1＝(d1+d2+d3+d4)/4，
……
e510＝(d510+d511+d511+d511)/4，
e511＝(d511+d511+d511+d511)/4。
e (n) — (d (n) + d (n +1) + d (n +2) + d (n +3))/M, and for points where n ═ 509, 510, and 511, points exceeding 511 among d (n +1), d (n +2), and d (n +3) are calculated as 511 points. The process is repeated for more than 2 times, and the transverse smoothing process of M L steps is finished.
According to one embodiment of the present invention, the comparing the fitted frequency response characteristic curve and the response frequency response characteristic curve by the processor 50 includes: averaging all points of the fitted frequency response characteristic curve to obtain a fitted average level value; averaging the response frequency response characteristic curve to obtain an initial average level value; the difference of the fitted average level value and the initial average level value is calculated.
Fig. 2 is a flowchart for sound field equalization using the speaker sound field equalizing apparatus of one embodiment of the present invention. As shown in fig. 2, the sound field equalization using the speaker sound field equalization apparatus of one embodiment of the present invention includes: in step 110, performing automatic equalization level adjustment, in step 120, acquiring a response frequency response characteristic curve generated by a sound source through the output of a loudspeaker, in step 130, adjusting a reference level with a fitting frequency response characteristic curve, in step 140, performing high-frequency adjustment, in step 150, performing a coarse adjustment curve, performing coarse adjustment on the envelope of the curve, in step 160, fine adjustment of the curve, adjusting a signal with a frequency within a range of 3dB, in step 170, fine adjustment of the curve, and adjusting a signal with a frequency within a range of 1 dB; finally, in step 180, the result of the equalization adjustment is determined, and if the result is qualified, the equalization adjustment is ended.
In the above scheme, regarding automatic equalization level adjustment:
because signal amplification and adjustment devices such as a power amplifier, an effector and the like are used in the KTV, the initial playing volume cannot be determined, and for the pink noise requiring large driving current, in order to prevent the sound equipment/loudspeaker from being damaged in the equalization process, the output level must be adjusted before starting data acquisition in the automatic equalization process.
The output is first turned off, initially at a-40 dB level, with the output intensity gradually increasing by 1 dB. Meanwhile, the acquired amplitude-frequency array is subjected to longitudinal 10-order smoothing processing to obtain a room frequency response curve of the current output level intensity, and the average level of the frequency response curve is obtained to obtain the average level of the current output level intensity. And when the level average level value exceeds the input set automatic equalization lowest level, the adjustment is completed, and the current average level is the automatic equalization output level. And after the adjustment is finished, calculating an automatic equalization adjustment scaling factor for determining the subsequent equalization level adjustment, wherein the automatic equalization adjustment scaling factor is equal to the curve average level/the automatic equalization lowest level. If the output level is increased to +5dB, the average level still can not reach the lowest level of automatic equalization, and the automatic equalization processing is stopped.
In the above scheme, with respect to obtaining the room initial characteristic frequency response curve:
and outputting pink noise by the level adjusted, collecting and carrying out 1024-point discrete Fourier transform, and carrying out 100-order longitudinal smoothing treatment on the 512-point amplitude-frequency array. And obtaining an initial characteristic frequency response curve of the room. The resulting curves are averaged. An initial room average level is obtained.
In the above scheme, the reference level of the curve to be fitted is adjusted
And averaging the input 512-point frequency response curve of the room to be fitted. And calculating the difference value of the average level value of the curve to be fitted and the initial average level of the room. And moving the curve to be fitted to the same average level value as the initial characteristic curve of the room. And after the level difference value is sequentially subtracted by 512 data of the curve to be fitted, the reference level of the curve to be fitted is adjusted, so that the curve to be fitted and the frequency response curve of the initial room have the same average level value.
According to one embodiment of the invention, the number of cycles of filtering of said filter of each level is greater than 1, the non-first filtering being dependent on the result of the previous filtering.
According to an embodiment of the present invention, the filter is a second-order equalization filter, and a boost level boost (n) of the second-order equalization filter is set to be (boost (n-1) + (frequency point level corresponding to a fitted frequency response curve-center frequency point level))) automatic equalization adjustment scaling factor; the automatic equalization adjustment scale factor is obtained by the following method: and setting the automatic equalization lowest level of a second-order equalization filter, wherein the automatic equalization adjustment scale factor is the ratio of the initial average level value to the automatic equalization lowest level.
In the above scheme, the equalization parameters of the second-order equalization filter are calculated as follows:
a1＝-2×cos(ω0)
b0＝1+alpha×A
b1＝-2×cos(ω0)
b2＝1-alpha×A
h(s) is the general second order filter transfer function, f0Is a high pass frequency point, Fs is a sampling rate, boost is a lifting level, a0～a2、b0～b2Are the operational parameters of the equalization filter. In the method, f0 is an equalization adjustment frequency point when the equalization filter is calculated, boost is the raised or lowered level of the equalization filter, and Q is the equalization filterAnd (4) Q value.
According to one embodiment of the present invention, the setting of the parameter for the high-frequency part of the adjusted response frequency response characteristic curve comprises: the central frequency point f0 is 16kHz and Q is 0.5 central frequency point/(central frequency point — bandwidth level corresponding frequency point).
Since the high-frequency components in the general KTV environment (sound equipment/loudspeaker) have large loss, the automatic equalization firstly carries out equalization fitting processing on the high frequency point. The parameters are set as follows:
if the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter.
The first adjustment equalization filter parameter generation formula of high frequency adjustment is as follows:
boost (boost + (the curve to be fitted corresponds to the frequency point level-the central frequency point level)). automatically and evenly adjusts the scale factor.
The high-frequency adjustment non-first adjustment equalization filter parameter generation formula:
boost (n) ((boost (n-1) + (frequency response curve to be fitted corresponds to frequency point level-center frequency point level))) automatic equalization adjustment scale factor
If the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter. F0 and Q parameters which are not adjusted for the first time adopt the values adjusted for the first time, and the difference between the level of the center frequency point after filtering and the level of the frequency point corresponding to the curve to be fitted is taken as the value of boost.
The parameter adjusting range of the high-frequency adjusting equalization filter is as follows:
| item | Adjustment range |
| f0 | 16KHz |
| boost | 5～20dB；-20db～-5dB |
| Q | 0.8～128 |
Fig. 3 is a flowchart for sound field equalizing high frequency adjustment using the speaker sound field equalizing apparatus of one embodiment of the present invention.
Wherein the total number of equalization filters is set to 22, and the number of equalization filters for high frequency adjustment is set to 5.
First, in step 310, it is determined whether the number of equalization filters already used is less than 22, if yes, it indicates that the equalization filtering process loop is not ended, in step 311, it is determined whether to adjust the equalization filtering for the first time, if yes, the equalization filter parameters are set according to the parameters of the high-frequency adjustment, that is: the central frequency point f0 is 16kHz, and Q is 0.5 central frequency point/(central frequency point — bandwidth level corresponding frequency point); in step 312, the center frequency point of the equalizing filter is set to 16kHz, in step 313, a frequency point with a setting value (bandwidth level) of the level difference from the center frequency point is searched from the center frequency point to the low frequency, in step 314, whether the level difference of the center frequency point is greater than the set filter enabling level is judged, if yes, in step 315, the frequency point, the Q value and the gain of the filter are calculated according to the center frequency point, the level difference of the center frequency point and the bandwidth frequency point; if not, in step 400, jump to the coarse tuning curve module; after step 315, executing step 316, subtracting 1 from the cycle number of the equalization filter, continuing to execute step 311, determining whether the adjustment is for the first time, if not, executing step 310, determining whether the remaining adjustment cycle number is 0, if so, indicating that the high frequency adjustment is finished, executing step 330, adding 1 to the high frequency adjustment number of the equalization filter, executing step 400, and jumping to a coarse tuning curve module; in step 320, when the remaining adjustment cycle number is not 0, step 321 is executed to determine whether the level difference of the central frequency point is greater than the set filter enabling level, if so, in step 322, the first adjusted Q value and frequency parameter are retained, the gain of the filter is calculated according to the level difference of the central frequency point, filtering is performed, in step 316, the cycle number of the equalization filter is decreased by 1, and step 311 is continuously executed.
In step 310, it is determined whether the number of equalization filters that have been used is less than 22, and if not, it indicates that the equalization filtering process loop has ended, and in step 500, it jumps to the adjustment result determination module.
According to one embodiment of the present invention, the parameter setting for coarse tuning further comprises setting: the central frequency point f0 is the frequency point farthest from the fitted frequency response characteristic curve in the current curve, and Q is 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
If the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter.
The rough tuning curve is used for adjusting frequency points with larger differences, and the parameters are set as follows:
according to one embodiment of the invention, when boost (n) exceeds the maximum level of the second order equalization filter, boost (n) is set to the maximum level of the second order equalization filter.
Coarse tuning a parameter boost level boost generation formula of an equalization filter for the first time:
boost (frequency point level-central frequency point level corresponding to curve to be fitted) automatic balance adjustment scale factor
The fine tuning non-first-time adjustment equalization filter parameter generation formula:
boost (n) ((boost (n-1) + (frequency response curve to be fitted corresponds to frequency point level-center frequency point level))) automatic equalization adjustment scale factor
If the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter. F0 and Q parameters which are not adjusted for the first time adopt the values adjusted for the first time, and the difference between the level of the center frequency point after filtering and the level of the frequency point corresponding to the curve to be fitted is taken as the value of boost.
And (3) coarsely adjusting the parameter adjusting range of the equalizing filter:
| item | Adjustment range |
| f0 | 90Hz～16KHz |
| boost | 5～20dB；-20db～-5dB |
| Q | 0.2～128 |
According to an embodiment of the present invention, the setting of the fine-tuned parameter further comprises: the central frequency point f0 is set to be the frequency point farthest from the fitted curve in the current curve, and Q is set to be 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
Fine tuning first adjustment equalization filter boost level boost parameter generation formula:
boost (frequency point level corresponding to the curve to be fitted-center frequency point level) and automatically balancing and adjusting the scale factor.
The fine tuning non-first-time adjustment equalization filter parameter generation formula:
boost (n) ((boost (n-1) + (frequency response curve to be fitted corresponds to frequency point level-center frequency point level))) automatic equalization adjustment scale factor
If the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter. F0 and Q parameters which are not adjusted for the first time adopt the values adjusted for the first time, and the difference between the level of the center frequency point after filtering and the level of the frequency point corresponding to the curve to be fitted is taken as the value of boost.
The fine tuning curve is used to fine tune the curve, and the parameters are set as follows:
fine tuning the parameter tuning range of the equalization filter:
| item | Adjustment range |
| f0 | 90Hz～16KHz |
| boost | 3～10dB；-10db～-3dB |
| Q | 0.2～128 |
According to an embodiment of the present invention, the setting of the parameters for fine tuning further comprises: the central frequency point f0 is set to be the frequency point farthest from the fitted curve in the current curve, and Q is set to be 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
Fine tuning a first adjustment equalization filter parameter generation formula:
boost (frequency point level-central frequency point level corresponding to curve to be fitted) automatic balance adjustment scale factor
The fine tuning non-first adjustment equalization filter parameter generation formula:
boost (n) ((boost (n-1) + (frequency response curve to be fitted corresponds to frequency point level-center frequency point level))) automatic equalization adjustment scale factor
If the boost set exceeds the maximum level of the filter, the boost test is forced to set to the maximum level of the filter. F0 and Q parameters which are not adjusted for the first time adopt the values adjusted for the first time, and the difference between the level of the center frequency point after filtering and the level of the frequency point corresponding to the curve to be fitted is taken as the value of boost.
The fine tuning curve parameters are set as follows:
and (3) fine tuning and adjusting the parameter adjusting range of the equalization filter:
the flow for the coarse, fine and fine tuning curves is the same as the flow for the high frequency tuning shown in fig. 3.
Input/output parameter specification of system
The input parameters are sampling rate, frequency response fitting curve and automatic equalization lowest level. The sampling rate is the sampling frequency of the audio signal ADC and is typically set to 44.1KHz or 48 KHz. The amplitude-frequency fitting curve is a 512-point array, and the serial number 0-511 of the array represents a frequency point which is the sampling rate/1024 array serial number; the values of the array represent the adjusted relative level values. The automatic equalization minimum level means that the minimum output level required by the automatic equalization adjustment can be normally carried out, and a user needs to set the minimum output level according to the volume when the KTV room sings.
The output parameters are the operation parameters of the 22-segment equalizing filter and the matched volume. The method adopts 22 sections of equalization filters to complete automatic equalization adjustment. After the adjustment, the average level of the output changes due to the action of the equalization filter, and needs to be compared with the initial room average level to find the matched volume, which is acted on the output end of the 22-segment equalization filter.
Description of system operating parameters:
fig. 4 is a flowchart for determining the adjustment result of sound field equalization using the speaker sound field equalizing apparatus according to the embodiment of the present invention. As shown in fig. 4, the determination of the sound field equalization adjustment result using the loudspeaker sound field equalization apparatus according to the embodiment of the present invention includes: in step 510, the adjusted equalization filter filters the pink noise and outputs the pink noise with an automatic equalization output level, in step 511, a frequency response characteristic curve of the pink noise is collected and a 100-order longitudinal smoothing amplitude-frequency curve is calculated, in step 512, whether longitudinal smoothing processing is finished or not is judged, and if yes, in step 513, an average level value of a current curve is calculated; if not, jumping to step 510; after the average level value of the current curve is calculated in step 513, in step 514, the automatic equalization matching volume is calculated, in step 515, whether the average level difference between the current curve and the fitting curve is less than 2 is judged, if yes, in step 516, 22 segments of equalization filter parameters and matching volume are output, and in step 517, the adjustment is judged to be successful; in step 515, it is determined whether the average level difference between the current curve and the fitted curve is less than 2, and if not, in step 518, it is determined that the adjustment has failed.
The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (11)
1. A loudspeaker sound field equalizing apparatus, comprising:
a collecting device for collecting the output of the sound source;
the sound source fitting device is used for generating a fitting frequency response characteristic curve for a sound source;
the processor is used for generating a response frequency response characteristic curve according to the output of the sound source collected by the collecting device, comparing the difference between the fitted frequency response characteristic curve and the response frequency response characteristic curve, and setting an equalizing filter with a corresponding grade according to the difference and different frequency bands;
the equalization filter is used for filtering the output of the sound source at a corresponding level and outputting the filtered sound source through a loudspeaker;
the acquisition device is further configured to: the system is used for collecting the output of the sound source filtered by the equalizing filter through a loudspeaker; and
the processor is further configured to:
and generating an adjusted response frequency response characteristic curve according to the sound source which is acquired by the acquisition device and filtered by the equalizing filter and output by a loudspeaker, comparing the adjusted response frequency response characteristic curve with the fitting frequency response characteristic curve, and performing filtering of the next level according to the comparison difference so that the adjusted response frequency response characteristic curve is consistent with the fitting frequency response characteristic curve, wherein the equalizing filters of different levels set different transfer function parameters.
2. The apparatus of claim 1, wherein the equalization filters are arranged in four stages, and the number of filters in each stage is several; the four levels of filters are sequentially configured to: for: adjusting high frequency, adjusting the high frequency part of the response frequency response characteristic curve; roughly adjusting envelope, and adjusting the signal which is farthest from the fitted frequency response curve; fine adjustment, adjusting the signal with the frequency within the range of 3 dB; and fine adjustment, namely adjusting the signal with the frequency within the range of 1 dB.
3. The apparatus of claim 2, wherein the processor generating a response frequency response profile from the output of the speaker comprises: collecting sound source output through a loudspeaker into the
And after the processor, performing discrete Fourier transform on the processor to generate an amplitude-frequency curve, and performing transverse and longitudinal smoothing on the amplitude-frequency curve to obtain a frequency response curve of the room, wherein the frequency response curve is used as the response frequency response characteristic curve.
4. The apparatus of claim 3, wherein the processor compares the difference between the fitted frequency response profile and the response frequency response profile comprises:
averaging all points of the fitted frequency response characteristic curve to obtain a fitted average level value;
averaging the response frequency response characteristic curve to obtain an initial average level value;
the difference of the fitted average level value and the initial average level value is calculated.
5. The apparatus of claim 4, wherein the number of cycles of filtering of each level of the equalization filter is greater than 1, and wherein non-first filtering is dependent on a result of a previous filtering.
6. The apparatus according to claim 5, wherein the filter is a second-order equalization filter, and the boost level boost (n) of the second-order equalization filter is set to be (boost (n-1) + (frequency response curve to be fitted corresponds to bin level-center bin level)) × automatic equalization adjustment scale factor;
the automatic equalization adjustment scale factor is obtained by the following method: and setting the automatic equalization lowest level of a second-order equalization filter, wherein the automatic equalization adjustment scale factor is the ratio of the initial average level value to the automatic equalization lowest level.
7. The apparatus of claim 6, wherein the parameter settings for the high frequency portion of the adjusted response frequency response characteristic comprise: the central frequency point f0 is 16kHz and Q is 0.5 central frequency point/(central frequency point — bandwidth level corresponding frequency point).
8. The apparatus of claim 6, wherein parameter settings for coarse tuning comprise setting: the central frequency point f0 is the frequency point farthest from the fitted frequency response characteristic curve in the current curve, and Q is 0.5 central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
9. The apparatus of claim 6, wherein when boost (n) exceeds the maximum level of the second order equalization filter, boost (n) is set to the maximum level of the second order equalization filter.
10. The apparatus of claim 6, the parameter settings for fine tuning comprising: and setting a central frequency point f0 as the frequency point farthest from the fitted frequency response characteristic curve in the current curve, and setting Q as 0.5 as the central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
11. The apparatus of claim 6, the parameter settings for the fine tuning comprising: and setting a central frequency point f0 as the frequency point farthest from the fitted frequency response characteristic curve in the current curve, and setting Q as 0.5 as the central frequency point/(high frequency point corresponding to bandwidth level-low frequency point corresponding to bandwidth level).
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| CN111314825A (en) * | 2018-12-11 | 2020-06-19 | 无锡华润矽科微电子有限公司 | System and method for automatically adjusting frequency response curve of loudspeaker |
| CN109803218B (en) * | 2019-01-22 | 2020-12-11 | 北京雷石天地电子技术有限公司 | Automatic calibration method and device for loudspeaker sound field balance |
| CN109889955B (en) * | 2019-01-28 | 2021-01-12 | 中科上声（苏州）电子有限公司 | Method and system for automatically balancing robustness of sound field in vehicle |
| CN111628838B (en) * | 2019-02-28 | 2021-06-08 | 中国科学院声学研究所 | Distributed emergency broadcast sound field homogenizing method |
| CN110913325A (en) * | 2019-11-26 | 2020-03-24 | 科大讯飞股份有限公司 | Automatic tuning method, related device and readable storage medium |
| CN110996242B (en) * | 2019-12-13 | 2021-03-02 | 科大讯飞(苏州)科技有限公司 | Tuning method, related device and readable storage medium |
| CN111356064A (en) * | 2020-03-12 | 2020-06-30 | 广州天逸电子有限公司 | EQ parameter generation method adaptive to real-time frequency response curve |
| CN111654781B (en) * | 2020-03-13 | 2021-08-10 | 广州励丰文化科技股份有限公司 | Low-frequency drive compensation method and system based on loudspeaker |
| US11617035B2 (en) | 2020-05-04 | 2023-03-28 | Shure Acquisition Holdings, Inc. | Intelligent audio system using multiple sensor modalities |
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