JPH10108300A - Sound field reproduction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sound field reproduction device by which crosstalk of speakers is cancelled at all times efficiently with respect to various speaker arrangement. SOLUTION: Signals R, L outputted from a source 30 are fed to any of crosstalk cancel circuits 6-10 in accordance with an installed position of speakers 30R, 30L. After the signals R, L are processed to eliminate crosstalk at a listening position of a listener, the processed signal is outputted to power amplifiers 31R, 31L and the signal is reproduced by the speakers 30R, 30L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound field reproducing apparatus for faithfully reproducing a sound field at the time of sound pickup.

[0002]

2. Description of the Related Art Conventionally, a transaural system has been known as a means for faithfully reproducing the sound pressure of a sound field from which sound has been collected (hereinafter referred to as an original sound field) at the ear of a listener using a speaker. I have. As a typical example of the transaural system, a reproducing apparatus using a crosstalk cancel circuit is known. In general, when sound collected by two channels in an original sound field using a dummy head is reproduced by left and right speakers in a sound field to be reproduced (hereinafter, referred to as a reproduction sound field), for example, sound emitted from a right speaker is desirable. Should reach only the right ear of the listener, but actually reach the left ear via a certain space transfer coefficient. This phenomenon is referred to as crosstalk, and is a great hindrance in faithfully reproducing the sound collected in the original sound field in the reproduction sound field.

Further, the sound reaching the right ear of the listener from the right speaker is also affected by the spatial transfer characteristics of the reproduced sound field, and it is desirable that such characteristics are not added. The crosstalk canceling circuit is a circuit that removes these characteristics. Specifically, the crosstalk canceling circuit includes a filter having a filter characteristic that removes the effect of the spatial transfer characteristic in the reproduced sound field, and uses a dummy head through this filter. The signal of the collected sound is reproduced. In addition, the filter characteristics of the above-described filter are calculated based on a standard arrangement of a so-called normal stereo reproduction in which left and right speakers are arranged at an angle of ± 30 ° in a horizontal plane with respect to a listener. ing.

[0004]

By the way, recently, an SD (stereo dipole) system in which left and right speakers are arranged in front of a listener in order to remove crosstalk has been adopted. For this reason, regarding the arrangement of the left and right speakers, there are a case where the speakers are used in a normal stereo arrangement state and a case where the speakers are arranged close to and in front of the listener as in the SD system. Since the conditions under which the crosstalk can be efficiently removed are different, there has been a problem that a single filter characteristic cannot cope with the crosstalk canceling circuit.

Also, speakers for televisions, mini components, radio cassettes, speakers for personal computers, etc.
The arrangement conditions of various speakers tend to be intermediate between the above-described ordinary stereo arrangement and the speaker arrangement of the SD system. In these cases, the conditions are not satisfied with the same filter characteristics, and good crosstalk elimination is not achieved. There was an inconvenience that it would not be possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a sound field reproducing apparatus that performs effective crosstalk cancellation in various speaker arrangements.

[0007]

According to a first aspect of the present invention, there is provided a sound field reproducing apparatus which faithfully reproduces an original sound field in a reproduced sound field. Means for removing crosstalk occurring at the listening position of the listener when the sound is reproduced by the two speakers installed in the speaker, and provided for each of a plurality of predetermined installation positions of the two speakers. And a plurality of crosstalk canceling units each set to remove the crosstalk most efficiently at a corresponding installation position of the two speakers, and one of the plurality of crosstalk canceling units. Selecting means for selecting and passing the two-channel sound signal input from the outside.

According to a second aspect of the present invention, there is provided a sound field reproducing apparatus which faithfully reproduces an original sound field in a reproduced sound field, comprising a plurality of filters whose filter characteristics are determined by coefficient data supplied from outside. By passing the input two-channel sound signal through the plurality of filters, crosstalk generated at the listening position of the listener when the sound is reproduced by the two speakers installed on the left and right front of the listener is removed. A crosstalk canceling means, and a set of coefficient data each having a filter characteristic such that each of the plurality of filters removes crosstalk most efficiently at each of a plurality of predetermined installation positions of the two speakers. Storage means for storing a plurality of sets corresponding to each of the plurality of installation positions, and a plurality of sets of coefficients stored in the storage means. Of over data, characterized in that by selecting a set of coefficient data and a data selection means for supplying to each of said plurality of filters.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. Such an embodiment shows one aspect of the present invention, and does not limit the present invention in any way, and can be arbitrarily changed within the scope of the present invention. First, FIG. 1 shows an arrangement of left and right speakers to which the sound field reproducing device of the present embodiment is applied. In this figure, 30R is a right speaker, 30L is a left speaker,
The right speaker 30R and the left speaker 30L are positioned at positions A and A ′ (± 5
゜), positions B and B ′ (± 15 °), positions C and C ′ (± 3
0 °), positions D and D ′ (± 45 °), positions E and E ′ (±
60 °). Here, in FIG.
Each installation angle of the right speaker 30R is indicated by + (plus), and each installation angle of the left speaker 30L is indicated by-(minus).
Is attached.

For the above-described five left and right speaker arrangements, the optimum filter characteristics in the crosstalk canceling circuit, that is, the filter characteristics capable of canceling the crosstalk most efficiently, are naturally different. In the sound field reproducing apparatus according to the present embodiment, for each speaker arrangement, a crosstalk canceling circuit having a filter having an optimum filter characteristic is prepared for each of the installation positions A, A 'to E, E' and used. The user can switch the crosstalk canceling circuit to be used according to the arrangement of the speakers 30R and 30L during reproduction.

Next, the appearance of the above-described sound field reproducing apparatus and the configuration of peripheral circuits of the sound field reproducing apparatus will be described with reference to FIG. In this figure, reference numeral 1 denotes a main body of the sound field reproduction device according to the present embodiment, which is output from a source 20.
The right acoustic signal R and the left acoustic signal L (hereinafter, simply referred to as signal R or L) are supplied, and a process is performed on each acoustic signal such that crosstalk is effectively removed according to the installation positions of the speakers 30R and 30L. After performing, the output is output to the power amplifiers 31R and 31L, respectively. The signals amplified by the power amplifiers 31R and 31L are output to the speaker 30.
It is emitted as a sound by R, 30L. Each of the signals R and L output from the source 20 is an acoustic signal of a sound collected on two channels by using a dummy head.

Reference numeral 2 denotes a power plug for supplying power to the main body 1, and reference numeral 4 denotes a power switch of the sound field reproducing apparatus. Reference numeral 3 denotes a neon tube, which lights up when the power switch 4 is turned on. Reference numeral 5 denotes a rotary switch, and “± 5
゜ ”,“ ± 15 ゜ ”,“ ± 30 ゜ ”,“ ± 45 ゜ ”,
It has five positions of “± 60 °”, and the user can operate the indication mark 5 indicated on the knob of the rotary switch 5.
a to the installation positions of the speakers 30R and 30L,
It can be set to any of the positions described above.

Thus, for example, the speakers 30R, 3
When 0L is set at the positions C and C ', as shown in FIG. 2, when the user sets the indication mark 5a to the position of "± 30 °", the signal output from the source 20 in the main body 1 is output. For R and L, speakers 30R and 30L
Are installed at the positions C and C ′, processing is performed so that crosstalk is most efficiently removed.

Next, a circuit configuration of the sound field reproducing apparatus according to the present embodiment will be described with reference to a block diagram shown in FIG. In this figure, a portion surrounded by a broken line shows a schematic circuit configuration in the main body 1 described above. In this figure, reference numerals 6 to 10 denote crosstalk cancel circuits, respectively. The crosstalk cancel circuit 6 can remove crosstalk most efficiently when the speakers 30R and 30L are installed at the positions A and A '. Filter characteristics. Similarly, the crosstalk cancel circuits 7 to 10 are connected to the speakers 30R and 30R.
L is the position B, B ', position C, C', position D,
It has a filter characteristic that can remove crosstalk most efficiently when installed at each of D 'and positions E and E'.

The signals R and L output from the source 20 are input to one of these crosstalk canceling circuits by the rotary switch 5, and the output from the crosstalk canceling circuit is supplied to the power amplifier 31R. , 31L are switched. That is, the rotary switch 5
Thus, in the speaker arrangement indicated by the indication mark 5a, the signal path is switched so as to pass through a crosstalk canceling circuit having a filter characteristic capable of removing crosstalk most efficiently.

For example, FIG. 3 shows a state in which the indication mark 5a of the rotary switch 5 is set to the position of "± 15 °". As a result, the signals R and L output from the source 20 are applied to the crosstalk cancel circuit 7.
And the speakers 30R and 30L are installed at the positions B and B ', processing is performed to remove crosstalk most efficiently, and the processed signals are sent to the power amplifiers 31R and 31L, respectively. After being output and amplified, it is emitted as sound from the speakers 30R and 30L.

Next, the configuration of the above-described crosstalk cancellation circuits 6 to 10 will be described with reference to FIG. In this figure, the portion surrounded by a broken line indicates the configuration of the crosstalk cancellation circuits 6 to 10. This configuration is common to each of the crosstalk cancellation circuits 6 to 10.

In this figure, 11 to 14 are FIR (Fi
The FIR filters 11 and 12 receive a signal R from a source 20, and the FIR filters 13 and 14 receive a signal L. Further, each of the FIR filters 11 to 14 has such a filter characteristic as to cancel the spatial transfer characteristic at the reproduction site at each of the installation positions of the speakers 30R and 30L. 15 and 16 are adders, and the adder 15 is F
The outputs of the IR filters 11 and 13 are added and output to the right speaker 30R via a power amplifier 31R (not shown). Further, the adder 16 adds the outputs of the FIR filters 12 and 14, and outputs the sum to a left speaker 30L via a power amplifier 31L (not shown).

Next, each filter characteristic of the FIR filters 11 to 14 will be described. First, consider the case where the signals R and L output from the source 20 are simply reproduced by the speakers 30R and 30L. For the sake of simplicity, it is assumed that the reproduced sound field is an anechoic room or a sound field with little reverberation. In this case, assuming that a signal reproduced at the right ear of the listener is S _r and a signal reproduced at the left ear is S _l , the signals S _r , S _l and the signals R, L output from the source 20 are different from each other. The relationship can be represented by the following matrix:

[0020]

(Equation 1) Here, H _Rr is the head-related transfer function from the speaker 30R to the right ear r of the listener LM, and H _Rl is the head-related transfer function from the speaker 30R to the listener L.
The head-related transfer function H _Lr from M to the left ear l is a head-related transfer function from the speaker 30L to the right ear r of the listener LM, and H _Ll is a head-related transfer function from the speaker 30L to the left ear l of the listener LM. .

In order to eliminate the influence of each head-related transfer function in the equation (1), the FIR filters 11 to 14 can be used.
For the matrix

(Equation 2) What is necessary is just to give the filter characteristic which becomes the inverse matrix of.

That is, the inverse of the matrix shown in equation (2) is

(Equation 3) Next, if the filter characteristics of the FIR filter 11 to 14 was H _A to H _D, respectively, each filter characteristic is as follows.

The FIR filter 11 filter characteristic _{H A H A = H Rr /} (H Ll · H Rr -H Lr · H Rl) ...... (3) of the FIR filter 12 filter characteristic H _B H _B = -H _Lr / _{(H Ll · H Rr -H Lr} · H Rl) ...... (4) filter characteristics of the FIR filter _{13 H C H C = -H Rl} / (H Ll · H Rr -H Lr · H Rl) ...... (5 ) the filter characteristic of the FIR filter _{14 H D H D = H Ll} / (H Ll · H Rr -H Lr · H Rl) ...... (6)

Here, a general configuration of the FIR filters 11 to 14 having the above-described filter characteristics will be described with reference to FIG. In FIG. 5, first, 1
7-1 to 17-N-1 are unit time delay elements connected in series to each other, and are signals x (n) (that is, signals R or L; n being output from the source 20 every sampling cycle). Indicates time in units of sampling period)
Is delayed by one sampling period. 18-1 to 1
8-N are multipliers, each of which has an input signal x (n) and
H (0) and multiplication coefficients of h (1) to h (N-1) given to the signals output from the unit time delay elements 17-1 to 17-N-1 in advance. Multiply by 19-1 to 1
9-N-1 are adders, and multipliers 18-1 to 18-18
The signals output from −N are sequentially added.

In the FIR filter shown in this figure, the following relationship exists between the input signal x (n) and the output signal y (n).

(Equation 4)

The input signal x (n) in the time domain, the output signal y (n), the multiplication coefficient h (n) and the input signal X in the frequency domain
(n), the output signal Y (n), and the multiplication coefficient H (n)
FT (Discrete Fourier Transform; Discrete Fourier Transform) and IDFT (Inverse Discrete Fourier Transform)
Transform: Inverse discrete Fourier transform) is represented by the following equation. DFT

(Equation 5) IDFT

(Equation 6)

Here, in the above-described FIR filter, the number of stages of the unit time delay element and the multiplication coefficient of each multiplier are measured values of the impulse responses from the speakers 30R and 30L to the right and left ears of the listener. Is designed and calculated based on

The sound field reproducing device shown in FIG. 3 includes a crosstalk canceling circuit having filter characteristics corresponding to the respective positions of the speakers 30R and 30L shown in FIG. , Signal R,
Although the crosstalk cancellation circuit for passing L is switched, only one crosstalk cancellation circuit is provided, and the multiplication coefficient and the like of each FIR filter are provided to the crosstalk cancellation circuit according to the installation position of the speaker. Alternatively, a plurality of storage means such as a memory may be stored in advance to supply the coefficients corresponding to the speaker installation position set by the user to each FIR filter.

[0029]

As described above, according to the first aspect of the present invention, the input two-channel sound signal is
Means for removing crosstalk occurring at a listening position of the listener when playing with two speakers installed at the left and right front of the listener, wherein each of a plurality of predetermined installation positions of the two speakers is provided. , A plurality of crosstalk canceling means, each of which is set to remove crosstalk most efficiently at the corresponding installation position of the two speakers, among the plurality of crosstalk canceling means, Selection means for selecting any one of the two channels and passing the two-channel audio signal input from the outside, so that crosstalk can be most efficiently performed at the speaker installation position in accordance with the speaker installation position. It is possible to select a crosstalk canceling means which is set to be removed, thereby providing one sound. The reproduction apparatus can perform crosstalk cancellation, which is always optimized in various speaker arrangement.

According to the second aspect of the present invention, there are provided a plurality of filters whose filter characteristics are determined by coefficient data supplied from the outside.
Crosstalk canceling means for removing crosstalk occurring at the listening position of the listener when reproducing by two speakers installed on the left and right front of the listener by passing the input two-channel acoustic signal,
At each of a plurality of predetermined installation positions of the two speakers, each of the plurality of filters transmits a set of coefficient data having a filter characteristic for removing crosstalk most efficiently. Storage means for storing a plurality of sets corresponding to each of the positions; and data selection for selecting one set of coefficient data from the plurality of sets of coefficient data stored in the storage means and supplying the selected set of coefficient data to each of the plurality of filters Means, it is not necessary to provide a number of crosstalk canceling means according to the installation position of the speaker, and by changing coefficient data to be supplied to each filter by one crosstalk canceling means, it is possible to provide various kinds of speakers. Even in the arrangement, the optimized crosstalk cancellation can always be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a speaker installation state to which a sound field reproducing device according to an embodiment of the present invention is applied.

FIG. 2 is an explanatory diagram for describing an external appearance of the sound field reproducing device and a configuration of a peripheral circuit of the sound field reproducing device.

FIG. 3 is a block diagram illustrating a schematic configuration of the sound field reproducing device.

FIG. 4 is a block diagram showing a configuration of a crosstalk cancel circuit used in the sound field reproducing device.

FIG. 5 is a circuit diagram showing a configuration of an FIR filter used in the crosstalk cancel circuit.

[Explanation of symbols]

1 ... body, 2 ... power plug, 3 ... neon tube, 4
... Power switch, 5 ... Rotary switch, 5a ...
Instruction marks, 6 to 10... Crosstalk cancel circuits, 11 to 14... FIR filters, 15, 16, 19
-1 to 19-N-1 adder, 17-1 to 17-N-1 unit time delay element, 18-1 to 18-N multiplier.

Claims (2)

[Claims] 1. A sound field reproducing apparatus that faithfully reproduces an original sound field in a reproduction sound field, wherein when an input two-channel acoustic signal is reproduced by two speakers installed on the left and right front of the listener, Means for removing crosstalk generated at a listener's listening position, provided for each of a plurality of predetermined installation positions of the two speakers, each of which corresponds to the installation position of the two speakers A plurality of crosstalk canceling means set so as to most efficiently remove crosstalk, and the two-channel sound input from outside by selecting any one of the plurality of crosstalk canceling means A sound field reproducing device comprising: a selection unit that allows a signal to pass therethrough. 2. A sound field reproducing apparatus which faithfully reproduces an original sound field in a reproduced sound field, comprising: a plurality of filters whose filter characteristics are determined by coefficient data supplied from the outside; Crosstalk canceling means for removing the crosstalk generated at the listening position of the listener when the sound is reproduced by the two speakers installed on the left and right front of the listener by passing the two-channel sound signal thus obtained; At each of the determined plurality of installation positions of the two speakers, each of the plurality of filters transmits a set of coefficient data having filter characteristics such that crosstalk is most efficiently removed by the plurality of installation positions. And a plurality of sets of coefficient data stored in the storage means.
A sound field reproducing device comprising: a data selecting unit that selects one set of coefficient data and supplies the selected coefficient data to each of the plurality of filters.