JP2950435B2 - Sound image controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls the waveform of an acoustic signal presented to both ears of a listener to change the position of a sound image perceived by the listener, so that the listener is in a desired acoustic space. The present invention relates to a sound image control device that gives an impression to a listener.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional sound image controller. An input terminal 11R, the input signal X _R to be presented to the right ear 13R of the listener 12, the signal X _R is the two first filter 1
4 _1, 14 ₂ speaker 15 are respectively processed in _1, 1
It is supplied to the 5 _2. The input terminal 11L, the signal X _L is input to be presented to the left ear 13L of the listener 12, the signal X _L
Are processed by the two second filters 16 ₁ and 16 ₂ , respectively, and supplied to the speakers 15 ₁ and 15 ₂ . Speaker 1
5 _1, 15 ₂ emits <br/> sound based on the signal processed to the reproduction sound field 1 7.

[0003] right ear 13R of the speaker 15 ₁ and the listener 12
And room transfer function between the left ear 13L (the impulse response) and G _11, G _12, respectively, G _21, respectively room transfer function between the right ear 13R and the left ear 13L of the speaker 15 ₂ and the listener 12 , and G _22, the first filter 14 _1, 1
4 each transfer function of the filter coefficients acting at ₂ and H _11, H _12, respectively, contact the second filter 16 _1, 16 ₂
The respective transfer functions of the filter coefficients acting on the filter are denoted as H ₂₁ and H ₂₂ , respectively. If the transfer function H ₁₁ satisfies the following equation ,
Filter coefficients giving H ₁₂ , H ₂₁ and H ₂₂ can be realized
If, acoustic, which is presented to the right ear 13R of the listener 12 X _R,
Sound that is presented to the left ear 13L is the X _L.

[0004] _{1 = G 11 H 11 + G} 21 H 12 0 = G 12 H 11 + G 22 H 12 0 = G 11 H 21 + G 21 H 22 (1) 1 = G 12 H 21 + G 22 H 22 That is, the input signal X _R, binaural 13R of Oite listener 12 between X _L and Nozomu Tokoro acoustic empty, and acoustic reaching the 13L etc.
Lever can be to the valence, the listener 12 to occur in the original sound field
The sound image can be perceived at the same position as the sound .

[0005]

However, the sound field in which such effects can be obtained by the conventional method has been limited to a room which has been subjected to advanced sound absorption processing such as an anechoic room. The reason is that, in a general room sound field where the influence of the reflected sound cannot be ignored, the room transfer functions G ₁₁ , G ₁₂ , G ₂₁ , and G ₂₂ shown in Expression (1) become non-minimum phase functions, and 1 / D ( Where D = G ₁₁ G ₂₂ −G
₁₂ G ₂₁ ) cannot be calculated, so the transfer functions H ₁₁ , H ₁₂ , H
_21, H ₂₂ not also be realized. The input signal and the listener's
Due to the fact that it is not possible to equalize the sound reaching both ears .

An object of the present invention, when the reproduction sound field is a common chamber can not be ignored the effects of reflected sound is also reproduced acoustic equivalent acoustic reaching the ears of the listener in the original sound field An object of the present invention is to provide a sound image control device that presents to both ears of a listener in a sound field, thereby allowing the listener to perceive the same sound image position as that of the original sound field, and giving an impression as if the user is in the original sound field.

[0007]

According to the present invention, S speakers (S is an integer equal to or greater than 3) are provided, and the S speakers provide S-th signals to be presented to the right ear of the listener. The signal to be presented to the left ear is processed by each of the S filters and processed by the S second filters.
Of speakers.

The room transfer functions between the speaker k (k = 1, 2,... S) and the right and left ears of the listener are G _k1 and G _k1.
Let _{k2 be} the transfer function of the first filter, H _1k , and the transfer function of the second filter be H _2k . _{1 = G 11 H 11 + G} 21 H 12 + ............... + G S1 H 1S 0 = G 12 H 11 + G 22 H 12 + ............... + G S2 H 1S 0 = G 11 H 21 + G 21 H 22 + G _S1 H _2s (2) 1 = G ₁₂ H ₂₁ + G ₂₂ H ₂₂ +... + G _S2 H _2S That is, the expression (2) is a signal X radiated from S speakers.
Component of _R is equal to the signal X _R reaches the right ear, but components of the signal X _R in the left ear becomes zero, the components of the signal X _L emitted from the S speaker reaches the left ear signal becomes the same as X _L, components of the signal X _L in the right ear shows a condition that a zero.

Here, the number of speakers is S, and each room transfer function (impulse response) G _{11 to} G _S1 , G _{12 to} G between each speaker and the right and left ears of the listener. _Assuming that _S2 is represented by a discrete time series (vector) of length m, it is used in the first and second filters so as to satisfy L> 2 (m-1) / (S-2) (3)
Transfer functions (FIR filter coefficients) H _{11 to} H _1S , H ₂₁ to
Determine the filter length L of H _2S. At this time, the transfer function H ₁₁
To H _1S and H _{21 to} H _2S can be uniquely determined. Decision
Constant transfer function H ₁₁ to H _1S, the H ₂₁ to H _2S first, second
If they are used as filter coefficients in the filter,
Listener of the right ear when the force signal X _R, is X _L is given, the left
Equivalent acoustic X _R, the X _L can be presented in the ear.

[0010]

1 shows an embodiment of the present invention and corresponds to FIG.
The same reference numerals are given to the parts to be performed. In this example, S = 3
Third speaker 15_ThreeProvided in the playback sound field 17
Can be In this case, the reproduction sound field 17 is like a normal room.
A reflected sound may be present. Speaker 15_ThreeWith the expansion of
Signal X_RThe first filter that processes₁, 14 _Twoof
14 others_ThreeIs increased and the signal X_LThe second fill that processes
16₁, 16_TwoIn addition to 16_ThreeIs increased. First,
Second filter, 14₁~ 14_Three, 16₁~ 16_ThreeEach
The filter coefficient is set by the filter setting unit 18. these
Filter 14 ₁~ 14_Three, 16₁~ 16_ThreeEach transfer function
H₁₁~ H₁₃, H_{twenty one}~ H_{twenty three}Is set to satisfy the following equation.
The filter coefficient of the filter is set.

[0011] _{1 = G 11 H 11 + G} 21 H 12 + G 31 H 13 0 = G 12 H 11 + G 22 H 12 + G 32 H 13 0 = G 11 H 21 + G 21 H 22 + G 31 H 23 (4) 1 = _{G 12 H 21 + G 22 H} 22 + G 32 H 23 G 31, G 32 right ear 13R of each speaker 15 ₃ and listener 12, a room transfer function between the left ear 13L.

The filter transfer functions H _{11 to} H satisfying the equation (3)
_13, determine the filter coefficients of the filter with H ₂₁ to H ₂₃ are available for example the techniques described in the specification of Japanese Patent Application Sho 60-53886. First and second filters 14 ₁ to 14 ₁
14 _3, 16 ₁ to 16 ₃ were each composed of FIR filters, when the filter length (3) the full to L, the filter coefficient can be represented by vectors as follows.

H₁₁= [H₁₁₁h₁₁₂............ h_11LH₁₂= [H₁₂₁h₁₂₂............ h_12LH₁₃= [H₁₃₁h₁₃₂............ h_13LH_{twenty one}= [H₂₁₁h₂₁₂............ h_21LH_{twenty two}= [H₂₂₁h₂₂₂............ h_22LH_{twenty three}= [H₂₃₁h₂₃₂............ h_23L] And each room transfer function G_ij(I = 1,2, j = 1,2)
Vector [g_ij1, G _ij2, ... g_ijm]. Each right
Target impulse response R for ear and left ear₁= [R₁₁r₁₂
... r_1n] R_Two= [R_{twenty one}r_{twenty two}... r_2n] Is R₁= [100 ...
0], R_Two= [000 ... 0], the following equation (5) is used.
If the filter coefficient that satisfies is obtained, the first filter 14₁~ 1
4_ThreeIs obtained.

[0014]

(Equation 5)

[0015]

Similarly, in the above formula, R ₁ = [000 ...
0], R ₂ = [100 ... 0], that is, the left side is [00 ... 010].
0... 0], and the filter coefficient on the right side is h
₂₁₁ h _{21 2} ... h _21L , h ₂₂₁ h ₂₂₂ ... h _22L , h ₂₃₁ h
₂₃₂ ... _H23L can be used to determine the filter coefficients of the second filters 16 _{1 to} 16 ₃ . The filter coefficients calculated in this way first, second filter 14 _1-14
3, 16 is set to ₁ to 16 _3, the speaker 15 ₁ to 1
5 right ear 13R of ₃ acoustic signals radiated from the listener 12
In the signal X _R terminals 11R, the left ear 13L at terminal 11L
Respectively equal to the signal X _L of. In other words, the use of this sound image control device allows the listener to perceive the same sound image position as that of the original sound field even in a room where the influence of the reflected sound cannot be ignored.

[0017]

As described above, according to the sound image control apparatus of the present invention, even when a room in which the influence of reflected sound cannot be ignored, that is, a room having a relatively long reverberation time, is used as a reproduced sound field, the listener can enjoy the sound. It is possible to freely control the sound signal waveform presented to both ears, and as a result, in any playback space, change the position of the sound image perceived by the listener and give the impression of being in the desired sound space. It can be given to the listener.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional sound image control device.

Claims (1)

(57) [Claims] 1. (A) S (S is an integer of 3 or more) first FIR filters 14 _k (1 ≦ k ≦ S) for inputting a signal to be presented to the right ear of a listener and processing each independently And (B) S second FIR filters 16 _k for inputting and independently processing signals to be presented to the left ear of the listener, and (C) output from the first FIR filter 14 _k. And (S) adders for adding an output from the second FIR filter 16 _k and an output from the second FIR filter 16 _k to output an S-channel signal, and (D) a signal for each channel output from the S adders. (E) transfer functions G _{11 to} G _S1 and G _{12 to} G _S2 from each of the S speakers to each of the left and right ears of one listener.
Are represented by discrete time series each having a length m, and the first FI
The filter lengths of the transfer functions H _{11 to} H _1S of the filter coefficients of the R filters 14 _{1 to} 14 _{k and} the transfer functions H _{21 to} H _2S of the filter coefficients of the second FIR filters 16 _{1 to} 16 _S are L, respectively. When there is L ≧ 2 (m−1) / (S−2), 1 = G ₁₁ H ₁₁ + G ₂₁ H ₁₂ +... + G _S1 H _1S 0 = G ₁₂ H ₂₁ + G ₂₂ H ₁₂ +... + G _S2 H _{1S 0 = G 11 H 21 + G} 21 H 22 + ... + G S1 H 2S 1 = G 12 H 21 + G 22 H 22 + ... + G S2 H 2S and so to satisfy the relationship, the first FIR filter 14 ₁ through 14 Each filter coefficient of _S and the second FI
Means for setting respective filter coefficients of the R filters 16 _{1 to} 16 _S.