CN111556425A - Tone equalization method for virtual sound reproduction of loudspeaker - Google Patents

Tone equalization method for virtual sound reproduction of loudspeaker Download PDF

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CN111556425A
CN111556425A CN202010310956.7A CN202010310956A CN111556425A CN 111556425 A CN111556425 A CN 111556425A CN 202010310956 A CN202010310956 A CN 202010310956A CN 111556425 A CN111556425 A CN 111556425A
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loudspeaker
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CN111556425B (en
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刘路路
谢菠荪
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South China University of Technology SCUT
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H04S3/008—Systems employing more than two channels, e.g. quadraphonic in which the audio signals are in digital form, i.e. employing more than two discrete digital channels
    • H—ELECTRICITY
    • 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
    • H—ELECTRICITY
    • 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
    • H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
    • H04S7/30—Control circuits for electronic adaptation of the sound field
    • H04S7/307—Frequency adjustment, e.g. tone control

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Abstract

The invention provides a tone equalization method for virtual sound reproduction of a loudspeaker, which inputs an original single-channel audio signalE 0(ii) a Processing the single-channel audio signal by a pair of auditory transmission synthesis filters to obtain two-channel signalsE L AndE R the pair of auditory transmission synthesis filters the single-path audio signal using a speaker virtual acoustic signal processing function including high-band power equalization and low-band multiplication by a frequency-independent gain factor, filtering the two-path signalE L AndE R respectively fed to the left and right loudspeakers symmetrically arranged in front of the horizontal plane. By passingThe invention introduces the crossover frequency, carries out power equalization on the virtual sound signal of the loudspeaker in a high frequency band above the crossover frequency, keeps the shape of a low frequency band amplitude spectrum unchanged, improves the tone color of the virtual sound replay of the loudspeaker, can avoid the insufficient low frequency of the replay, and does not influence the virtual source positioning of the replay.

Description

Tone equalization method for virtual sound reproduction of loudspeaker
Technical Field
The invention relates to the technical field of electroacoustic, in particular to a tone equalization method for virtual sound reproduction of a loudspeaker.
Background
Loudspeaker virtual sound reproduction, also called auditory transmission reproduction, is a spatial sound reproduction technique. It uses head related transfer function signal processing to control binaural sound pressure in speaker playback, thereby using a small number of speakers to generate perceived virtual sources in different spatial directions. One typical application of speaker virtual sound reproduction is virtual surround sound reproduction, which uses a pair of speakers arranged in front of a listener to generate a virtual speaker in a front half-horizontal plane, thereby enabling reproduction of signals of multi-channel surround sound with a small number of speakers. This approach has been applied to virtual playback of 5.1-channel and other multi-channel surround sound, such as Dolby virtual surround sound technology, SRS and Qsurround technology, among others. Another typical application of loudspeaker virtual sound reproduction is sound reproduction in computer games, with a pair of loudspeakers arranged on both sides of the computer display to achieve a spatial sound localization effect.
One problem with virtual sound reproduction from loudspeakers is that the sound quality changes during reproduction, which affects the effect of the reproduction. There is a need to add tone equalization signal processing to improve playback. A full (audible) band power equalization method in the range of 20Hz to 20kHz is disclosed in the national patent of invention grant (ZL 02134416.7). The method can reduce the change of the reproduced tone color to a certain extent. In the national patent of invention grant (ZL200610037495.0), the head-related transfer function filters for signal processing are simplified and the change in the reproduced timbre is further reduced. However, the timbre equalization signal processing involved in the two national patent applications still suffers from the low frequency inadequacy of reproduced sound.
Disclosure of Invention
The invention further provides a tone color equalization method for virtual replay of the loudspeaker on the basis of the prior art. The method introduces a tone color equalization method of a frequency division band in the virtual sound signal processing of the loudspeaker, can further reduce the change of tone color in the playback process, particularly reduce low-frequency loss, and can not sense the virtual source direction.
The invention discloses a tone equalization method for virtual sound reproduction of a loudspeaker, which comprises the following steps:
inputting an original single-path audio signal E0；
Processing the single-channel audio signal by a pair of auditory transmission synthesis filters to obtain a two-channel signal ELAnd ERSaid pair of auditory transmit synthesis filters filtering the single path audio signal with a loudspeaker virtual acoustic signal processing function comprising a high band power equalization and a low band multiplied by a frequency independent gain factor,
will two-path signal ELAnd ERRespectively fed to the left and right loudspeakers symmetrically arranged in front of the horizontal plane.
In one embodiment, the virtual sound signal processing function of the speaker including the high-band power equalization and the low-frequency multiplied by the frequency-independent gain factor is specifically as follows:
EL＝G'L(θS,f)E0ER＝G'R(θS,f)E0
Figure BDA0002457565930000021
Figure BDA0002457565930000022
wherein, G'L(θSF) is the left speaker signal processing function, G'R(θSF) is the right speaker signal processing function, α and β represent the transfer functions from the two speakers to the ipsilateral and ipsilateral ears, respectively, HL(θSF) and HR(θSAnd f) respectively represent an azimuth angle thetaSTo the left and right ears of the target virtual source of (1); f represents frequency; f. of0Is a frequency division point which represents high frequency and low frequency and is larger than f0Is a high frequency band, less than f0Low frequency band is obtained; g0Is representative of the low frequency gainIs constant.
In one embodiment, the frequency division frequency f0Obtained by the following method:
in diffuse sound field approximation, the center frequency is fCThe normalized cross-correlation coefficient of the acoustic signal generated at two sound receiving points separated by Δ r is:
Figure BDA0002457565930000023
where Ψ represents the normalized cross-correlation coefficient, kcRepresenting wave number, c 343m/s is sound velocity due to | sin (k)CDelta r) | is less than or equal to 1, and the maximum value | Ψ ∞ of the normalized cross-correlation coefficientmax≤(kCΔr)-1Given this maximum, the division frequency is obtained:
Figure BDA0002457565930000024
in one embodiment, Δ r is an average distance between two ears, and the corresponding frequency f is divided0＝1.5kHz。
In one embodiment, the low frequency gain constant G0At a dividing frequency f according to the power spectrum of the high frequency band and the low frequency band0And selecting nearby continuous conditions.
The principle of the invention is as follows: in loudspeaker virtual sound reproduction, the virtual source position is determined by the relative amplitude and relative phase between the channel signals. The simultaneous multiplication or division of the loudspeaker signals by a common factor related to frequency does not affect the position of the virtual source, but changes the power spectrum of the loudspeaker signals so that the reproduced timbre can be equalized. In an ideal diffusion field, sound pressures generated by a plurality of loudspeakers at sound receiving points are not in correlated superposition, so that the power equalization is carried out on each loudspeaker signal, and the total power spectrum of each loudspeaker signal is not changed along with the frequency change. In practice, however, reproducing the sound field in a room is not an ideal diffuse sound field. Particularly at low frequencies, the sound pressure at the sound receiving point is not an uncorrelated superposition of the sound pressures generated by the loudspeakers. Power equalization throughout the full band range (from 20Hz to 20kHz) can result in excessive low frequency attenuation, causing insufficient low frequency playback. Since the sound field of the actual playback room is relatively close to the diffuse sound field above a certain frequency, the power of the virtual sound signal of the loudspeaker can be equalized in a high frequency band above the certain frequency, and the amplitude spectrum shape of the signal is kept unchanged by multiplying a low frequency band below the certain frequency by a gain factor irrelevant to the frequency. This makes it possible to improve the reproduction of high-frequency timbres while avoiding the disadvantages of low frequencies.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention introduces the frequency division frequency, the frequency band above the frequency division frequency is a high frequency band, the frequency band below the frequency division frequency is a low frequency band, the power of the virtual sound signal of the loudspeaker is balanced in the high frequency band, the amplitude spectrum shape of the signal is kept unchanged in the low frequency band, the tone color of the virtual sound reproduction of the loudspeaker is improved, the insufficient low frequency of the reproduction can be avoided, and the invention does not influence the virtual source positioning of the reproduction.
2. The invention can be used for virtual replay of various multi-channel (such as 5.1 channels) surround sound, and can also be used for computer sound replay and game replay.
Drawings
Fig. 1 is a block diagram of a tone equalization method for virtual sound reproduction of a speaker according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a virtual playback speaker arrangement and speaker to binaural transmission.
Fig. 3 is a result of a virtual source location experiment demonstrating the present invention.
Fig. 4 is a result of a subjective evaluation test for timbre in accordance with the present invention.
Detailed Description
The present invention will be described in further detail with reference to the following drawings and examples, but the scope of the present invention is not limited thereto.
A block diagram of the system of the present invention is shown in fig. 1. A pair of real horizontal speakers are arranged in front left and front right directions of a listener. Inputting an original single-path audio signal E0(ii) a For single-channel audio signal through a pair of auditory transmission synthesis filtersProcessing to obtain two-path signal ELAnd ERThe pair of auditory transmission synthesis filters the single-path audio signal using a speaker virtual acoustic signal processing function including high-band power equalization and low-band multiplication by a frequency-independent gain factor, filtering the two-path signal ELAnd ERRespectively fed to the left and right loudspeakers symmetrically arranged in front of the horizontal plane.
The audio signal is processed by a pair of auditory transmission synthesis filters and then fed to the left front loudspeaker and the right front loudspeaker for reproduction respectively. The response of the acoustic transmission synthesis filter is obtained by equalizing binaural sound pressures reproduced by the two speakers to that of the target sound source and adding a tone equalization process.
The azimuth angle of the horizontal plane is selected to be more than or equal to 0 degree<360 °, where θ is 0 °,90 °,180 °, and 270 ° represent right front, right, rear, and left directions, respectively. For the horizontal angle theta in the free fieldSThe sound pressure of the ears can be respectively transmitted from the sound source to the Head Related Transfer Function (HRTF) H of the left earL(θSF) Head Related Transfer Function (HRTF) H of the right earR(θSAnd f) obtaining:
PL(f)＝HL(θS,f)E0(f) PR(f)＝HR(θS,f)E0(f) (2)
where f denotes the frequency, E0＝E0(f) Is the amplitude signal of the sound source, HL(θSF) and HR(θSAnd f) respectively represent an azimuth angle thetaSTo the left and right ear.
For the virtual reproduction of the two loudspeakers shown in fig. 2, the azimuth angles of the two loudspeakers are thetaLAnd thetaR. Four transfer functions (HRTFs) from two loudspeakers to two ears are respectively HLL(θL，f)，HRL(θL，f)，HLR(θRF) and HRR(θRF) the two loudspeaker signals are respectively ELAnd ER. Reproducing the generated binaural sound pressure to produce a stack of binaural sound pressures for two loudspeakersAdding:
Figure BDA0002457565930000041
considering left-right symmetry, the transfer functions from the two loudspeakers to the ipsilateral ear are equal, and the transfer functions to the different ears are also equal:
HLL(θL,f)＝HRR(θR,f)＝α HLR(θR,f)＝HRL(θL,f)＝β (4)
(3) is formed as
P'L(f)＝αEL+βERP'R(f)＝βEL+αER(5)
When equation (2) is equal to equation (5), that is, when binaural sound pressure generated by virtual playback is equal to the target sound source, signals of the two speakers are obtained as follows:
EL＝GL(θS,f)E0ER(f)＝GR(θS,f)E0(6)
where the response of a pair of auditory transmitters is
Figure BDA0002457565930000042
Whereby the two loudspeaker signals are transmitted using a pair of acoustic transmission filters GL(θSF) and GR(θSF) to the input signal E0And (4) filtering to obtain the filter.
High frequency power equalization is the equalization of a pair of auditory transmission responses of equation (7) with a common factor that is frequency dependent. Equalization with a constant power factor will cause the response of the auditory transmission filter to become:
Figure BDA0002457565930000051
the denominator of the above equation is a common factor of constant power, which is frequency dependent. Keeping the total power of the high-frequency band signal unchanged after equalization:
|G'L(θS,f)|2+|G'R(θS,f)|2＝1 (9)
the embodiment adopts a tone equalization method with sub-bands: at the frequency of division f0In the high frequency band, power equalization processing is added; for frequency division frequency f0The following low frequency bands are not increased in frequency-dependent equalization but merely multiplied by a frequency-independent gain factor G0So that the power spectra of the high and low bands are continuous around the crossover frequency. After the equalization process, a pair of auditory transmission filter responses shown in formula (1) is obtained.
EL＝G'L(θS,f)E0ER＝G'R(θS,f)E0
Figure BDA0002457565930000052
Figure BDA0002457565930000053
Frequency division frequency f0This is selected as follows. In diffuse sound field approximation, the center frequency is fCThe normalized cross-correlation coefficient of the acoustic signal generated at two sound receiving points separated by Δ r is:
Figure BDA0002457565930000054
where c is 343m/s is the speed of sound. Due to | sin (k)CDelta r) | is less than or equal to 1, and the maximum value | Ψ ∞ of the normalized cross-correlation coefficientmax≤(kCΔr)-1Given this maximum, the division frequency can be obtained
Figure BDA0002457565930000055
If the average distance between ears is selected as 0.175m, the correlation coefficient | Ψ is not zeromaxWhen the ratio is 0.1, 0.2 and 0.3, the results are divided intoFrequency f03.1kHz, 1.6kHz and 1.0kHz respectively. Considering that the low-frequency binaural time difference of 1.5kHz is the main localization factor of virtual sound reproduction of the loudspeaker, in order to make this factor not affected by equalization, the crossover frequency in the embodiment of the present invention is taken as f0This also allows the correlation coefficient to approach 0.2 at 1.5 kHz.
The principle of the embodiment of the invention is as follows:
in loudspeaker virtual sound reproduction, the virtual source position is determined by the relative amplitude and relative phase between the channel signals. The simultaneous multiplication or division of the loudspeaker signals by a common factor related to frequency does not affect the position of the virtual source, but changes the power spectrum of the loudspeaker signals so that the reproduced timbre can be equalized. In an ideal diffusion field, sound pressures generated by a plurality of loudspeakers at sound receiving points are not in correlated superposition, so that the power equalization is carried out on each loudspeaker signal, and the total power spectrum of each loudspeaker signal is not changed along with the frequency change. In practice, however, reproducing the sound field in a room is not an ideal diffuse sound field. Particularly at low frequencies, the sound pressure at the sound receiving point is not an uncorrelated superposition of the sound pressures generated by the loudspeakers. Power equalization throughout the full band range (from 20Hz to 20kHz) can result in excessive low frequency attenuation, causing insufficient low frequency playback. Since the sound field of the actual playback room is relatively close to the diffuse sound field above a certain frequency, the present embodiment performs power equalization on the virtual sound signal of the speaker in the high frequency band above the certain frequency while maintaining the amplitude spectrum shape of the low frequency band signal, thereby improving the playback high frequency tone color and avoiding the deficiency of the low frequency.
The embodiment can be realized by a general DSP hardware circuit or a special integrated circuit, and can also be realized on a multimedia computer by software programmed by an algorithm language (such as VC + +).
The embodiment can be designed into special hardware or general software for sound reproduction in aspects of digital televisions, intelligent loudspeaker systems and the like, and can also be used as hardware or software for sound reproduction of multimedia computers.
For ease of understanding, the following describes the application of the inventive arrangements to a multimedia computer.
Reading the single-pass signal stored in the hard disk by the computer or obtaining the single-pass signal through a digital transmission medium such as the internet, and then using the computer software to execute the virtual signal processing of fig. 1 (or using a dedicated hardware circuit on the sound card of the computer) to obtain the two-pass signal ELAnd ERThen the two full-frequency band loudspeakers are respectively fed to an external connection or a computer for reproduction.
The signal processing in the embodiment of the invention uses head-related transfer function data of a KEMAR artificial head, and the length of the head-related transfer function data is 512 points, and the sampling frequency is 44.1 kHz. Virtual signal processing is implemented using Finite Impulse Response (FIR) filters.
The method comprises the following specific steps:
the first step is as follows: inputting a single-channel audio signal E0；
The second step is that: one-channel signal is used by a band division filter G 'of the left channel'L(θSF) and a band-dividing filter G 'of the right channel'R(θSF) filtering to obtain two-channel output signals ELAnd ER；
Psychoacoustic experiments were used to verify the practical effects of the embodiments of the present invention. One key to evaluating embodiments of the present invention is the perceived direction and subjective timbre quality of each virtual source. The embodiment will compare and evaluate the following three speaker virtual sound signal processing methods using different equalization methods.
(1) The method comprises the following steps: and (4) processing the virtual sound signal without tone equalization. The two loudspeaker signals are obtained by signal processing according to the above equations (6) and (7).
(2) The second method comprises the following steps: a power equalization method in the full audible frequency band range of 20Hz-20 kHz. The two loudspeaker signals are obtained according to the preceding equations (6) to (8).
(3) The third method comprises the following steps: power equalization method for high frequency band with frequency dividing point of f01.5 kHz. The two loudspeaker signals are obtained according to the formula (1), namely the tone color equalization method provided by the invention.
The single-channel audio signal is processed by one of the methods described above to obtain two speaker signals. Signal processing was performed using a KEMAR artificial head (with DB-060/061 pinna small). The sampling frequency of the signal processing filter is 44.1kHz, and the length is 512 points. The signal processing is implemented in software on a computer, and the signal is reproduced by a sound card (RME fire UC) and a pair of loudspeakers.
The experiment was carried out in a listening room with a reverberation time of 0.15 s. The speakers are arranged in the direction of ± 15 ° azimuth from the horizontal plane, 1.45m from the listener's head center. The replay pressure level is approximately 80 dB.
The experiment was divided into two parts. The first part is a virtual source localization experiment. The experimental signal is a section of orchestra (selected from Bo Liao, magic symphony) with a length of 10 s. Selection of thetaSIn the experiment, the subjects judged the perceived virtual source direction, 12 subjects, aged 22-30 years, three times for each subject, and thus there were a total of 3 subjects with × 12 total judges for each condition, 36 judges.
The Kruskal-Wallis H test was first used to analyze the consistency of the experimental data. The average and standard deviation of the 36 judgments were taken as the final experimental results. And simultaneously, the results of the three equalization methods are tested by an analysis of variance method.
The results of the Kruskal-Wallis H test indicate that at a significance level α of 0.05, there is no difference in significance for all tests, and thus the results of all subjects and replicates are consistent, so the results of the experiment are stable and reliableSThe results of further analysis of variance show that at a significance level α of 0.05, the positioning results of the three equalization methods have no significant difference, the significance of the perceived azimuth angle is 0.85, and the significance of the perceived elevation angle is 0.352, which are both greater than 0.05.
The second part of the experiment was a subjective evaluation of perceived timbre quality. Adopting a plurality of test signals recommended by the International telecommunication Union,Including the quantitative evaluation method of the hidden reference and anchor signals (MUSHRA, ITU-R, bs.1534-3, 2015), the timbre quality of different equalization methods was compared. For each of the three equalization methods, for θSThe virtual source timbres for 7 horizontal target directions, 0 °, 15 °, 30 °, 45 °, 60 °, 75 ° and 90 °, were evaluated. The signals used for evaluation include the following five music signals:
(1) czochralski, 1812 sequence fragment
(2) Boliaozi magic symphony segment
(3) Do Ni Geti, much beautiful one-day fragment, selected from the opera military girls
(4) Rossini, Williams desserts fragment
(5) Picture segment at the Moxolski, exhibition
For each case (given the equalization method, target virtual source angle and signal), the reference and hidden reference are the original single-path signals reproduced with a single loudspeaker in the target direction. The low anchor signal is the signal of the first equalization method described above with 7kHz low pass filtering. Thus, there are six signals in each case, including a reference signal, a hidden reference signal, a low anchor signal, and three signals for different equalization methods. The subjects evaluated five targets on a scale of 0 to 100 points, including a hidden reference signal, a low anchor signal, and three signals for different equalization methods. Wherein: scores 0 to 20 indicate very poor, scores 20 to 40 indicate poor, scores 40 to 60 indicate good, scores 60 to 80 indicate good, and scores 80 to 100 indicate good. Each subject was evaluated three times for each target, thus giving a score of 36 for 3 replicates × 12 subjects.
The raw evaluation results were subjected to multivariate analysis of variance with a confidence level of 0.05. Analysis of variance includes three factors, the method of equalization, the signal and the target virtual source direction. And simultaneously checking the interaction among the factors.
The preliminary statistical t-test shows that the average score of the timbre of the hidden reference is not significantly different from the 100-point full score, while the average score of the low anchor is significantly different from the 100-point. The Kruskal-Wallis H test showed that at the significance level α of 0.05, there was no significant difference in all replicates. The result of the timbre evaluation is thus valid.
TABLE 1 results of multivariate analysis of variance on perceived timbre
Figure BDA0002457565930000081
Table 1 shows the results of multivariate analysis of variance on perceived timbre. The equalization method and the target azimuth have significant influence on the perceived timbre. But the signal has no significant effect on the perceived timbre. The balance method and the target azimuth angle have obvious interaction; but there is no significant interaction between the signal and the target azimuth and between the equalization method, the signal and the target azimuth. There is thus a significant difference between the three equalization methods, although the difference is related to the target azimuth.
Fig. 4 shows the result of the subjective timbre assessment experiment, i.e. the average perceived timbre scores of the five music signals, twelve subjects and three repeated judgments used for the assessment under the condition of three different equalization methods and different target virtual source azimuth angles. The basic result is that the ordering of timbre high scores to low scores is: the third equalizing method, the second equalizing method and the first equalizing method.
Further analysis of variance showed that:
(1) at the target virtual source azimuth (i.e., the target azimuth in the figure) θSWhen the value is equal to 0 degrees, the third equalizing method and the second equalizing method have no obvious difference; but the equalization method three and one and the equalization method two and one have significant differences.
(2) At the target virtual source azimuth angle theta S15 ° (actual speaker direction), there is no significant difference between the three equalization methods.
(3) At other target virtual source azimuth angle theta S30 °, 45 °, 60 ° and 90 °, there are important differences in the three equalization methods.
The average timbre of the power equalization method for the high frequency band is mainly in the "better" range of 60-70 minutes, better than 50-60 minutes ("fair" range) of the power equalization method in the full audible frequency band, and significantly better than about 40 minutes ("poor" range) of the unvoiced equalization.
The above experiment shows that the power equalization method of the high frequency band can further improve the perceived timbre quality and has no influence on the virtual source positioning. Therefore, the effect of the invention is verified through experiments.
As above, to facilitate understanding, embodiments of the present invention specifically present multimedia computer applications. However, the present invention is not limited to the application of multimedia computer, and may also include other applications, such as the application of blue-ray disc player and the application of television, after decoding the output of blue-ray disc player or processing each channel (digital) signal of multi-channel surround sound obtained from digital transmission medium according to the method of fig. 1, obtaining two-channel signal ELAnd ERAnd then feeds a pair of stereo speakers on the television set to reproduce the effect of spatial surround sound. The virtual signal processing can be used as a part of hardware circuit in a blue-ray disc player, a part of hardware circuit of a television or a hardware circuit in an active loudspeaker system; as another example, in a home theater application, the multi-channel surround sound (digital) signal decoded by a blu-ray disc player or obtained from a digital transmission medium is fed to an amplifier of the home theater, and the virtual signal processing of fig. 1 is implemented as a part of the functional circuitry in the amplifier. Obtain a two-path signal ELAnd ERAnd then the signals are respectively fed to the external left and right full-frequency band loudspeakers for reproduction. The invention is not limited to the implementation in software in a computer, but may be implemented in other ways, such as a general-purpose DSP, designed as a dedicated integrated circuit chip.

Claims (5)

1. A method of tone equalization for virtual sound reproduction by a loudspeaker, comprising the steps of:
inputting an original single-path audio signal E0；
Processing the single-channel audio signal by a pair of auditory transmission synthesis filters to obtain a two-channel signal ELAnd ERThe pair of auditory transmission synthesis filters employs speaker virtual sound including high band power equalization and low band multiplication by a frequency-independent gain factorThe signal processing function filters the single path audio signal,
will two-path signal ELAnd ERAre fed to the left and right loudspeakers, respectively, which are arranged in front of the horizontal plane.
2. The method of claim 1, wherein the speaker virtual sound signal processing function comprising high-band power equalization and low-frequency multiplication by a frequency-independent gain factor is as follows:
EL＝G'L(θS,f)E0ER＝G'R(θS,f)E0
Figure FDA0002457565920000011
Figure FDA0002457565920000012
wherein, G'L(θSF) is the left speaker signal processing function, G'R(θSF) is the right speaker signal processing function, α and β represent the transfer functions from the two speakers to the ipsilateral and ipsilateral ears, respectively, HL(θSF) and HR(θSAnd f) respectively represent an azimuth angle thetaSThe transfer function of the target virtual source to the left ear and the right ear; f represents frequency; f. of0Is a frequency division point which represents high frequency and low frequency and is larger than f0Is a high frequency band, less than f0Low frequency band is obtained; g0Is a constant representing the gain at low frequencies.
3. Method for tone equalization of the virtual sound reproduction of loudspeakers according to claim 2, characterised in that said crossover frequency f0Obtained by the following method:
in diffuse sound field approximation, the center frequency is fCIs generated at two sound receiving points which are separated by delta rThe normalized cross-correlation coefficient of (a) is:
Figure FDA0002457565920000013
where Ψ represents the normalized cross-correlation coefficient, kcRepresentative wave number, c 343m/s is sound velocity since | sin (k)CDelta r) | is less than or equal to 1, and the maximum value | Ψ ∞ of the normalized cross-correlation coefficientmax≤(kCΔr)-1Given this maximum, the division frequency is obtained:
Figure FDA0002457565920000021
4. a method as claimed in claim 3, characterized in that said Δ r is the average distance between the ears, the corresponding crossover frequency f0＝1.5kHz。
5. The method of claim 2, wherein the low frequency gain constant G is a constant that is constant for the timbre equalization of the virtual sound reproduction of the loudspeaker0At a dividing frequency f according to the power spectrum of the high frequency band and the low frequency band0And selecting nearby continuous conditions.
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113645531A (en) * 2021-08-05 2021-11-12 高敬源 Earphone virtual space sound playback method and device, storage medium and earphone
CN114827884A (en) * 2022-03-30 2022-07-29 华南理工大学 Method, system and medium for spatial surround horizontal plane loudspeaker placement playback
CN115604646B (en) * 2022-11-25 2023-03-21 杭州兆华电子股份有限公司 Panoramic deep space audio processing method

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080279318A1 (en) * 2007-05-11 2008-11-13 Sunil Bharitkar Combined multirate-based and fir-based filtering technique for room acoustic equalization
CN103634726A (en) * 2013-08-30 2014-03-12 苏州上声电子有限公司 Automatic loudspeaker equalization method
CN106535043A (en) * 2016-11-18 2017-03-22 华南理工大学 Full-frequency 3D virtual sound customization method and device based on physiological characteristics
CN107222808A (en) * 2017-05-03 2017-09-29 上海大学 A kind of high-fidelity loudspeaker playback system design method
CN207075075U (en) * 2017-09-01 2018-03-06 珠海煌荣集成电路科技有限公司 A kind of virtual bass generative circuit and audio frequency apparatus
CN109686347A (en) * 2018-11-30 2019-04-26 北京达佳互联信息技术有限公司 Sound effect treatment method, sound-effect processing equipment, electronic equipment and readable medium
CN109714681A (en) * 2019-01-03 2019-05-03 深圳市基准半导体有限公司 A kind of device and its implementation of the digital audio 3D that sample rate is adaptive and audio mixing effect
CN110809222A (en) * 2018-08-06 2020-02-18 深圳瑞利声学技术股份有限公司 Multi-section dynamic range control method and system and loudspeaker

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20080279318A1 (en) * 2007-05-11 2008-11-13 Sunil Bharitkar Combined multirate-based and fir-based filtering technique for room acoustic equalization
CN103634726A (en) * 2013-08-30 2014-03-12 苏州上声电子有限公司 Automatic loudspeaker equalization method
CN106535043A (en) * 2016-11-18 2017-03-22 华南理工大学 Full-frequency 3D virtual sound customization method and device based on physiological characteristics
CN107222808A (en) * 2017-05-03 2017-09-29 上海大学 A kind of high-fidelity loudspeaker playback system design method
CN207075075U (en) * 2017-09-01 2018-03-06 珠海煌荣集成电路科技有限公司 A kind of virtual bass generative circuit and audio frequency apparatus
CN110809222A (en) * 2018-08-06 2020-02-18 深圳瑞利声学技术股份有限公司 Multi-section dynamic range control method and system and loudspeaker
CN109686347A (en) * 2018-11-30 2019-04-26 北京达佳互联信息技术有限公司 Sound effect treatment method, sound-effect processing equipment, electronic equipment and readable medium
CN109714681A (en) * 2019-01-03 2019-05-03 深圳市基准半导体有限公司 A kind of device and its implementation of the digital audio 3D that sample rate is adaptive and audio mixing effect

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
石蓓 谢菠荪: "虚拟听觉重放与听觉声源宽度的扩展", 《华南理工大学学报(自然科学版)》 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113645531A (en) * 2021-08-05 2021-11-12 高敬源 Earphone virtual space sound playback method and device, storage medium and earphone
WO2023010691A1 (en) * 2021-08-05 2023-02-09 高敬源 Earphone virtual space sound playback method and apparatus, storage medium, and earphones
CN113645531B (en) * 2021-08-05 2024-04-16 高敬源 Earphone virtual space sound playback method and device, storage medium and earphone
CN114827884A (en) * 2022-03-30 2022-07-29 华南理工大学 Method, system and medium for spatial surround horizontal plane loudspeaker placement playback
CN115604646B (en) * 2022-11-25 2023-03-21 杭州兆华电子股份有限公司 Panoramic deep space audio processing method

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