JP2924539B2 - Sound image localization control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound image localization control method for causing a sound image to be localized at a desired arbitrary position different from an actual transducer (speaker).
In particular, the present invention relates to a sound image localization control method that can be mounted on an amusement game machine, a computer terminal, or the like, has an excellent sound image localization feeling, and can reduce the circuit scale.

[0002]

2. Description of the Related Art Conventionally, there is a sound image localization method in which a sound source can be felt at a specific position (specific direction) by a signal level difference and a phase difference (time difference) in both ears. As a sound image localization method realized by a digital circuit, for example,
There is a "method and apparatus for forming a sound image" described in JP-A-2-298200. This method of sound image localization using a digital circuit is based on a method in which a signal from a sound source is FFT (Fast Fourier Transfor
m) Convert and process on the frequency axis, give both the left and right channel signals a frequency-dependent level difference and phase difference,
It controls the localization of the sound image digitally. The frequency-dependent level difference and phase difference at each sound image localization position of this device are collected as experimental data (psychological data) using an actual listener. However, in order to accurately and precisely localize a sound image by this sound image localization method, the circuit scale becomes large, so that it has only been used as a special professional recording system. At the recording stage, sound image localization processing (for example, movement of flying sound) is performed, and a sound (music) signal resulting from the processing is recorded. The processed signal is reproduced by a normal stereo reproduction device, thereby producing a sound image moving effect.

[0005] Recently, amusement game machines and computer terminals using virtual reality have appeared. Also in these game machines and terminals, demands for sound image localization with a sense of reality corresponding to the screen have begun. For example, in a game machine, the movement of a flying sound that matches the movement of an airplane on a screen is beginning to be required. In this case, if the flight course of the airplane is determined, the sound (music) obtained by moving the sound image in accordance with the movement is inserted in advance, and the sound (music) is simply reproduced on the game machine side. Is enough.

However, in a game machine (or a terminal device), the course (position) at which an airplane flies depends on the operation of the operator, and the moving process of the sound image suitable for the operation in real time according to the operation. Need to be regenerated. This point is significantly different from the above-described sound image localization processing for a record. For this reason, a sound image localization device is required for each game machine. However, in the above-described method, it is necessary to perform FFT on a signal from a sound source, process the signal on a frequency axis, perform inverse FFT on the signal again, and reproduce the signal. Therefore, the circuit scale tends to be large. In addition, since the sound image localization is based on the data on the frequency axis (the transfer characteristics of the level difference and the phase difference depending on the frequency), the approximation of the HRTF (head-related transfer function) cannot be performed accurately. Of all sound image localization positions (360
Degree), the transfer characteristics could not be retained.

Accordingly, the present applicant has invented a new sound image localization method as an alternative to the conventional sound image localization method, and has described a “method of sound image localization control” (filing date: November 30, 1992). Sound image localization control device ”(filing date: December 1992
On March 18). This sound image localization method
A signal from a sound source is processed on a time axis by a pair of convolvers to localize a sound image, and a transfer characteristic for sound image localization (coefficient of a convolver) is finally adjusted to an IR (impulse response) on a time axis. It is data. The outline of this sound image localization method will be described below with reference to the principle diagram shown in FIG. In the figure, sp1 and sp2 are a pair of speakers arranged at the front left and right of the listener,
The head transfer characteristic (impulse response) from sp1 to the listener's left ear is h1L, and the head transfer characteristic from the right ear to h1R is s.
The head transfer characteristics from p2 to the left and right ears are defined as h2L and h2R. Further, the head transfer characteristic to the listener's left and right ears when an actual speaker is placed at the target localization position x is pL.
x, pRx. Here, each transfer characteristic is obtained by actually measuring and performing appropriate waveform processing or the like using a speaker in an acoustic space and microphones arranged at both ears of a dummy head (or a human head). Then, the sound source (source) X to be localized is passed through signal conversion devices cfLx and cfRx (transfer characteristics by a convolver or the like), and the processed signals are reproduced by the speakers sp1 and sp2, respectively. At this time, cfLx = (h2R · pLx−h2L · pRx) / H cfRx = (− h1R · pLx + h1L · pRx) / H where H = h1L · h2R−h2L · h1R, using transfer characteristics cfLx and cfRx. A signal to be localized is processed by a convolver (convolution operation processing circuit) or the like. Then, the sound image is localized at the target position x and heard by the listener. In this case, the head transfer characteristics h1L,
h1R, h2L, h2R, and the head transfer characteristics pLx, when an actual speaker is placed at a target localization position x,
As pRx, IR (impulse response) actually measured by actually installing a speaker at each angle was used.
That is, the physical H with respect to the physical sound image position described later
RTF (head-related transfer function) was measured and used.

[0006]

However, in the above-described new sound image localization method by the present applicant, depending on the sound source, there is a case where ambiguity remains in the localization position of the sound image. However, there were still points to be improved, such as the fact that they could be heard as multiple sound images and that they could not be heard from the intended localization position.

[0007]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, the same sound source is supplied from a plurality of transducers arranged at a distance and a predetermined transmission is performed. A sound image localization control method that reproduces signals processed by a plurality of signal conversion circuits having characteristics and makes a listener feel that a sound image is localized at an arbitrary position different from the transducer.
The first is the head related transfer function (HRTF) with the listener
Step of measuring HRTF (101a, 102a)
A second HRTF corresponding to the localization position of the sound image.
Measuring the HRTF of (101b, 102b)
The measured first HRTF and the measured second HRTF
(104) determining a transfer characteristic for the signal conversion circuit at each sound image localization position based on the above, setting the determined transfer characteristic in the signal conversion circuit, and processing a signal from the sound source. A sound image localization control method characterized by comprising the step (106) of reproducing by the transducer.

[0008]

According to the sound image localization control method as described above, FIG.
As shown in, the HRTF (head-related transfer function) at each sound image localization position is the head between the transducer and the listener.
Corresponds to the first HRTF that is the transfer function and the localization position of the sound image
Accurate approximation processing is performed based on the second HRTF that is the head-related transfer function obtained, and the transfer characteristics (coefficient data cfLx, cfRx of impulse response) of the plurality of signal conversion circuits (a pair of convolvers 1 and 2) are obtained. ). Since the measurement is based on the physical HRTF, the measurement of the HRTF is easy, and since the measurement is based on the psychological HRTF, the sound image localization is excellent in consideration of the auditory characteristics. The signal from the sound source (X) is convolved on the time axis by a plurality of signal conversion circuits (a pair of convolvers 1 and 2), and a plurality of transducers (a pair of speakers) (sp1, sp2). The sound reproduced from the transducer is sound localized so that the sound source is located at a desired arbitrary position (x) with the crosstalk to both ears cancelled, and the sound is heard by the listener (for example, a game operator) M. It is.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a sound image localization control method according to the present invention will be described below with reference to the drawings. First, the basic principle of the sound image localization control method will be described. This is a technique in which a sound image is localized at an arbitrary position in a space using a pair of transducers (hereinafter, a speaker will be described as an example) that are arranged apart from each other.

FIG. 3 is a diagram showing the principle of sound image localization. sp1,
sp2 is a speaker arranged at the front left and right of the listener M. The head transfer characteristic (impulse response) from sp1 to the listener's left ear is h1L, and the head transfer characteristic from the right ear to the head is h1.
The head transfer characteristics from R, sp2 to the left and right ears are h2L, h
2R. Further, when there is a sound image at a target localization position x, the head transfer characteristics to the listener's left and right ears are pLx and pR.
x. Here, each transfer characteristic is obtained by actually measuring and performing appropriate waveform processing or the like using a speaker in an acoustic space and microphones arranged at both ears of a dummy head (or a human head).

Next, signals obtained by passing a sound source X to be localized through signal conversion devices cfLx and cfRx (transfer characteristics by a convolver or the like) are respectively converted into sp1 and sp
Consider playing on 2. At this time, if the signals obtained from the listener's left and right ears are eL and eR, eL = h1L · cfLx · X + h2L · cfRx · X (Equation 1) eR = h1R · cfLx · X + h2R · cfRx · X (〃) On the other hand, source X Let dL and dR be the signals obtained at the listener's left and right ears when reproducing from the target localization position, dL = pLx · X (Equation 2) dR = pRx · X (〃)

Here, if the signals obtained at the listener's left and right ears by the reproduction of sp1 and sp2 coincide with the signals at the time of reproducing the source from the target position, the listener can make the speaker appear as if at the target position. It will recognize the sound image. From the conditions eL = dL, eR = dR and (Equation 1) and (Equation 2), X is eliminated and h1L · cfLx + h2L · cfRx = pLx (Equation 3) h1R · cfRx + h2R · cfRx = pRx (〃) (Equation 3) ), CfLx = (h2R · pLx−h2L · pRx) / H (Equation 4a) cfRx = (− h1R · pLx + h1L · pRx) / H (〃) where H = h1L · h2R−h2L · h1R (Equation 4b) Therefore, if a signal to be localized by a convolver (convolution operation processing circuit) or the like is processed using the transfer characteristics cfLx and cfRx calculated by (Equation 4a) and (Equation 4b), the target position x can be obtained. The sound image can be localized.

Various methods for realizing a specific signal conversion device are conceivable, but they may be realized using an asymmetric FIR digital filter (convolver). The final transfer characteristic when used in the FIR digital filter is a time response function. That is, as the transfer characteristics cfLx and cfRx at the required localization position x, those obtained by (Equation 4a) and (Equation 4b) are used as coefficients for realizing by one FIR filter process, and the coefficients cfLx and cfRx are used. It is created in advance and prepared as ROM data. R
If the necessary sound image fixed position coefficient is transferred from the OM to the FIR digital filter, the signal from the sound source is convolution-processed and reproduced from a pair of speakers, the sound image is localized at a desired arbitrary position.

The sound image localization control method according to the present invention based on the above principle will be described in detail with reference to FIGS. 1, 2 and 4 to 6. FIG. 1 shows steps of a sound image localization control method, and FIG. 2 is a configuration diagram of a sound image localization control device.
Sound localization control method according to the present invention, (a) the physical HRTF for physical sound image position (first HRTF), psychological HRTF for psychological sound image position (second HRT
F), and based on the measured physical HRTF and psychological HRTF, coefficients cfLx and cfRx of a pair of convolvers at each sound image localization position were obtained.
(B) The psychological HRTF is measured for each divided frequency band and synthesized as an IR (impulse response). (C) The width of the divided frequency band is a critical bandwidth. Has its features.

Here, the physical HRTF with respect to the physical sound image position is defined as an angle θ in a space in which the front face of the speaker SP is set to 0 degree (°) in FIGS. 4 and 5 (for example, as shown in FIG. 5). As described above, the head-related transfer function is physically measured by the pair of microphones ML and MR in a state where the head-mounted transfer function is actually set at 24 points every 15 degrees. In addition, the psychological HRTF for the psychological sound image position is a position in FIG. 4 where the front is 0 ° (°) in the direction of the angle θ in the space and the position where the sound image is actually felt. With the speaker SP installed, a pair of microphones M
L and MR are head-related transfer functions. That is, it is a head-related transfer function measured in consideration of a psychological evaluation (aural characteristic).

Physical and psychological head-related transfer functions (Head
Measurement of Related Transfer Function (referred to as HRTF) (Steps 101a and 101b) This will be described with reference to FIGS. FIG. 4 shows the HRTF
1 shows a measurement system. A pair of microphones ML and MR are installed at both ears of the dummy head (or human head) DM, receive a measurement sound from the speaker SP, and a recorder DAT.
Source sound (reference data) refL, refR
And the measured sound (measurement data) L and R are recorded in synchronization with each other.

When measuring the physical HRTF for the physical sound image position, white noise is used as the source sound XH. A plurality of angles θ (for example, in a space where the position of the speaker SP is determined as 0 degrees (°) in the front)
As shown in FIG. 5, it is set at 24 points every 15 degrees), and is continuously recorded for a predetermined period of time.
Are the physical HRTF data (measurement data L, R).

Further, at the time of measuring the psychological HRTF for the psychological sound image position, a signal sound having a critical bandwidth, for example, a signal sound having a critical bandwidth (band-limited to a critical bandwidth by a band-pass filter) is used as the source sound XH. White noise). At this time, a listener is placed at the position of the dummy head (or head) DM, and it is psychologically considered that there is actually a sound image in the direction of the angle θ in the space determined as 0 degrees (°) in front. The source sound XH is reproduced and measured with the speaker SP installed at a position where the user can feel it. In this state, the HRTFs measured for each critical bandwidth are
Psychological HRTF data at the angle θ (measurement data L,
R).

Calculation of physical and psychological HRTF impulse responses (hereinafter referred to as IR) (steps 102a and 102b) In step 101, source sounds (reference data) refL and refR recorded synchronously. And a measured sound (measurement data) L and R are transmitted to a workstation (not shown).
Process above. If the frequency response of the source sound (reference data) is X (S), the frequency response of the measured sound (measurement data) is Y (S), and the frequency response of the HRTF at the measurement position is IR (S), (Equation 5) There is an input / output relationship shown in FIG. Y (S) = IR (S) · X (S) (Equation 5) Therefore, the frequency response of the HRTF is expressed by IR (S) = Y (S) / X (S) (Equation 6) is there.

Therefore, the frequency response X of the reference
(S) The frequency response Y (S) of the measured data is cut out from the data obtained in step 101 with a time-synchronous window, and finite Fourier series expansion is performed by the FFT transform to calculate a discrete frequency. 6) From frequency response IR (S) of physical HRTF and psychological HRTF
Is obtained by a well-known calculation method. In addition, the psychological HRTF data group measured for each critical bandwidth is synthesized for each angle θ, and one psychological HRTF data is set for each angle θ.
It is said.

As described above, there are two reasons why the psychological HRTF is obtained by measuring each critical bandwidth. The psychological sound image position is easily affected by the frequency of the sound source, and if the HRTF is determined for each frequency band and the sound image is not localized,
Inability to hear from the intended localization position, ambiguity in the localization position of the sound image when performing sound image processing on a sound source with a wide frequency band, or sound reproduction as a single sound image as multiple sound images Because it becomes. However, if the psychological sound image position (psychological HRTF) is considered too much,
The measurement becomes enormous and practicality is lost. In general, human hearing is called the critical band, `` they use sound-discrimination and frequency analysis based on band-pass characteristics arranged along the entire audible frequency band, and the pass band is narrower for lower frequencies and wider for higher frequencies. ''
It has the characteristic that. Therefore, the present invention focuses on this critical band, and sets a psychological H for each of the divided critical bandwidths.
RTF is measured, and an effective number of data and an effective psychological HRTF are measured.

In order to improve the accuracy of the IR (S) (improve the SN ratio), it is preferable to calculate the IR (S) for each of several hundred different windows and average them.
Then, the calculated frequency response IR (S) of the HRTF is subjected to an inverse FFT transform, and a physical and psychological IR for each angle θ is obtained as a time axis response (impulse response) of the HRTF.

IR (Impulse Response) Shaping Process (Step 103) Here, the IR obtained in Step 102 is shaped. First, the IR obtained in step 102 by, for example, FFT conversion
Is developed at a discrete frequency over the audio spectrum to be IR (S), and unnecessary bands (a large dip occurs in a high frequency band, which is an unnecessary one that does not significantly affect sound image localization) are converted into BPFs (bandpasses). Filter). When the band is limited in this manner, unnecessary peaks and dips on the frequency axis are removed, and unnecessary coefficients are not generated in the cancel filter, so that convergence is improved and the coefficients can be shortened.

Then, the band-limited IR (S) is converted into the inverse F
The FT conversion is performed, and an IR (impulse response) is multiplied by a cutout window (for example, a window of a cosine function) on the time axis, and a window process is performed. By performing the window processing, the effective length of the IR is no longer long, the convergence of the cancel filter is improved, and the sound quality does not deteriorate.

Cancel filters cfLx, cfRx
(Step 104) The cancellation filters cfLx and cfRx, which are convolvers (convolution integrators), are, as shown in (Equation 4a) and (Equation 4b), cfLx = (h2R · pLx−h2L · pRx) / H (Formula 4a) cfRx = (− h1R · pLx + h1L · pRx) / H (() where H = h1L · h2R−h2L · h1R (Formula 4b).

Here, the speakers sp1 and sp
2 transfer characteristics h1L, h1R, h2L, h2R
Each angle θ obtained in steps 101 to 103 as the head transfer characteristics pLx and pRx when the sound image is actually felt at the target localization position x.
The physical and psychological IRs (impulse responses) that have been shaped for each are substituted.

The head transfer characteristics h1L and h1R are represented by L in FIG.
It corresponds to the position of the channel speaker, and if it is installed at, for example, 30 degrees (θ = 330 degrees) from the front to the left, a physical IR of θ = 330 degrees is used. The head transfer characteristics h2R and h2L correspond to the position of the R channel speaker in FIG.
If it is set at 30 degrees, a physical IR of θ = 30 degrees is used (that is, a system that is close to a system at the time of actual sound image reproduction (for example, shown in FIG. 2 described later) is selected).

The head-related transfer characteristics pLx and pRx are 90 degrees from the front which is the target sound source localization position.
The range of 180 degrees is of course (24 in FIG. 6).
A position at 0 degree is taken as an example), and a psychological IR for every 30 degrees in a wide space (all spaces) beyond that is substituted. As a result, the corresponding space cfLx,
cfRx, that is, 24 sets of cancellation filters cfLx and cfRx are obtained for every 15 degrees actually measured. The group of cancellation filters cfLx and cfRx is finally determined as an IR (impulse response) which is a response on the time axis.

The scaling of the cancellation filter at each localization point x (step 105) The spectrum distribution of the sound source (source sound) actually subjected to sound image processing by the convolver (cancellation filter) is statistically similar to pink noise. In some cases, the sound source is different from a single sound, so there is a danger that the convolution operation (integration) will overflow and cause distortion. is there. Therefore, in order to prevent overflow, when the coefficient having the largest gain is found among the coefficients of the cancel filters cfLx and cfRx, and all the coefficients are convolved with the white noise of 0 db, all the coefficients are changed so as not to cause overflow. Scale.

[0030] Then, the wind window (cosine window), (in the present embodiment, the final cancellation filters scaling process is referred to as a combo Luba) actual convolver in accordance with the number of coefficients, both ends Window processing is performed so that the coefficient length becomes 0, and the effective length of the coefficient is shortened. A data group which is thus scaled and finally supplied to the convolver as a coefficient (in this example, a coefficient group of 24 sets of convolvers capable of localizing a sound image every 15 degrees) cf
Lx and cfRx are obtained.

The signal from the sound source is convoluted and reproduced (step 106). For example, as shown in FIG.
A pair of loudspeakers sp1 and sp2 are disposed at regular intervals so that sound signals processed by a pair of convolvers (convolution operation processing circuits) 1 and 2 are reproduced on the pair of loudspeakers sp1 and sp2. Constitute. Coefficient ROM3
Include 24 sets of convolver coefficient groups cfLx and cfRx for every 15 degrees obtained in steps 101 to 105.
Is stored.

The pair of convolvers 1 and 2 have the same sound source X (for example, a flight sound from a game synthesizer).
And the desired coefficient cfLx,
cfRx (for example, the flight sound is 120 degrees to the left rear (θ = 24
When it is desired to localize the sound image at the position of 0 °), a coefficient of θ = 240 °) is selected and set in the convolvers 1 and 2.
For example, a main CPU (central processing unit) of a game machine or the like
Sub C for control based on sound image localization command from
The PU 4 transfers the coefficient at the desired localization position from the coefficient ROM 3 to the pair of convolvers 1 and 2.

In this manner, the pair of convolvers 1 and 2
The signal from the sound source X is subjected to convolution calculation processing on the time axis, and a pair of speakers sp
1 and sp2. A pair of speakers sp1, s
The sound reproduced from p2 is canceled out of the crosstalk to both ears, the sound image is localized so that the sound source is located at a desired position, and the sound is heard by the game operator (listener) M, which is very realistic. Played as sound. As for the coefficients of the convolvers 1 and 2, the optimal sound image position is sequentially selected and switched with the transition of the movement of the airplane according to the operation of the operator M. Also, when changing from a flight sound to a missile sound, for example,
The source sound from the sound source X is changed from the flight sound to the missile sound. In this way, the sound image can be freely localized at any position.

As described in detail above, according to the present sound image localization control method, the physical HRTF for the physical sound image position is determined.
And the psychological HRTF with respect to the psychological sound image position are measured, and these physical HRTF (IR) and psychological HRTF are measured.
Based on F (IR), coefficient groups cfLx, cfR of 24 sets of convolvers 1 and 2 capable of localizing a sound image every 15 degrees
Since x is obtained, the auditory characteristics (that is, the psychological sound image position depends on the frequency of the sound source) are reflected in the coefficients of the convolvers 1 and 2, and the sound image localization feeling is extremely high. Be sharp and clear.

Further, a psychological HRTF is provided for each frequency band.
The sound image is localized, so the sound image cannot be heard from the intended localization position, and the sound image is not clear.
It does not occur due to problems the hearing of characteristics such as that. That is, all the problems of the conventional “method of sound image localization control” invented earlier by the present applicant are solved. further,
In addition, since the psychological HRTF is measured for each of the divided critical bandwidths by focusing on the critical band, an effective number of data and an effective psychological HRTF can be measured, which is extremely practical. . That is, Japanese Unexamined Patent Application Publication No.
As in “Sound image forming method and apparatus” described in Japanese Patent Publication No. 298200, all data is not based on psychological evaluation, so that the number of measured data does not become enormous.

As a transducer for reproduction, a headphone can be used instead of the pair of speakers sp1 and sp2. In this case, since the measurement conditions of the HRTF are different, it is preferable to prepare a coefficient separately and switch according to the reproduction state. Also, the I shown in step 103
The shaping process of R (impulse response) is not always necessary, and even if it is omitted, the sound image localization can be controlled.

The configuration described in the embodiment for reproducing a signal processed by a pair of convolvers supplied with the same sound source from a pair of transducers (loudspeakers) disposed separately from each other provides an effect of sound image localization. It shows the minimum configuration to obtain. Therefore, if necessary, a pair, that is, two or more transducers and convolvers may be additionally configured. Further, when the coefficient of the convolver is long, the coefficient may be divided into a plurality of parts. It may be composed of convolvers.

[0038]

As described above in detail, according to the sound image localization control method according to the present invention, the same sound source is supplied from a plurality of transducers arranged at a distance and a plurality of transducers having a predetermined transfer characteristic are provided. A sound image localization control method for reproducing a signal processed by a signal conversion circuit to make a listener feel that a sound image is localized at an arbitrary position different from that of the transducer.
Measuring a first HRTF that is a head-related transfer function (HRTF), and using an HRTF corresponding to a localized position of the sound image.
Measuring a certain second HRTF; obtaining a transfer characteristic for the signal conversion circuit at each sound image localization position based on the measured first HRTF and the second HRTF; Setting the transfer characteristics in the signal conversion circuit, processing the signal from the sound source, and reproducing the signal with the transducer, so that the sense of sound image localization becomes clear.

Further, a second HRTF is provided for each frequency band.
In the case of sound image localization in which the sound image is localized, there is no problem caused by auditory characteristics such as ambiguity of the localization position of the sound image, inability to hear from the intended localization position, and hearing of a single sound image as multiple sound images. . In particular, in the case where the second HRTF is measured for each of the divided critical bandwidths by focusing on the critical band, the measurement can be performed with an optimized number of data and effectively.
Come, it is very practical.

Accordingly, the sound image localization control can be performed by mounting the apparatus on a small and inexpensive device such as a consumer game machine or a computer terminal, and the sound image localization feeling can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating an embodiment of a sound image localization control method according to the present invention.

FIG. 2 is a basic configuration diagram of a sound image localization apparatus using a sound image localization control method according to the present invention.

FIG. 3 is a configuration diagram showing a basic principle of a method of sound image localization control.

FIG. 4 is a configuration diagram showing an HRTF (head-related transfer function) measurement system.

FIG. 5 is a diagram illustrating points of HRTF measurement.

FIG. 6 is a diagram illustrating calculation of a cancel filter.

[Explanation of symbols]

1, 2 Signal conversion circuit (convolver) 3 Coefficient ROM 4 Coefficient supply means (sub CPU) 101a Step of measuring physical HRTF 101b Step of measuring psychological HRTF for each critical bandwidth 102a Calculate impulse response of physical HRTF Step 102b Psychological HR by combining data for each critical band
Step of calculating the impulse response of the TF 103 Step of shaping the IR (impulse response) 104 Step of calculating the cancel filter (transfer characteristic) 105 Step of scaling the cancel filter 106 Convolution calculation and reproduction of the signal from the sound source Steps sp1, sp2 Speakers h1L, h1R Head transfer characteristics from the speaker sp1 to the listener's left and right ears h2L, h2R Head transfer characteristics from the speaker sp2 to the listener's left and right ears pLx, pRx Actual sound image at the intended localization position x by placing the speaker to be felt that there is, the head-related transfer characteristic cfLx up to the measured listener's left and right ears, cfRx coefficient of convolver (coefficient of the cancellation filter) DM dummy head (poll) M listener (game Operator) X sound source x purpose and The sound image localization position that

Claims (3)

(57) [Claims] 1. A signal which is supplied from a plurality of transducers spaced apart and which is supplied with the same sound source and processed by a plurality of signal conversion circuits having predetermined transfer characteristics, is reproduced.
In a sound image localization control method for causing a listener to feel that a sound image is localized at an arbitrary position different from the transducer, a head-related transfer function between the transducer and the listener is provided.
Measuring a first HRTF that is (HRTF); and a second HRTF that is HRTF corresponding to the localization position of the sound image.
Measuring the HRTF of the signal conversion circuit, determining a transfer characteristic for the signal conversion circuit at each sound image localization position based on the measured first HRTF and the second HRTF, and determining the determined transfer characteristic Is set in the signal conversion circuit, and a signal from the sound source is processed and reproduced by the transducer. 2. The sound image localization control method according to claim 1, wherein the second HRTF is measured for each of divided frequency bands and synthesized as an IR (impulse response). 3. A divided frequency band width, the sound image localization control method according to claim 2, characterized in that the critical bandwidth.