JPH02219400A - Stereophonic sound reproducing device - Google Patents

Abstract

PURPOSE:To execute the stereophonic acoustic reproducing of a multi-channel sound signal by a headphone by combining plural delay circuits and filters and processing the sound signal by a correction and synthesization circuit. CONSTITUTION:A simple correction and synthesization circuit 27 is formed by combining plural delay circuit 8-15 and filters 16-25. Thus, for multi-channel sound signals (a)-(c) of a signal source circuit 6, the output sounds of plural speakers (four speakers, for example) based on these sound signals arrive at the right and left ears of a listener 1. The sound signals are corrected and synthesized to a frequency and a phase characteristic at such a time and two channel sound signals (l) and (r) for stereophonic acoustic reproducing are formed. Since this sound signal is supplied to a headphone 26, the stereophonic acoustic reproducing can be executed in the headphone 26 by using the sound signals (a)-(c) of the circuit 6. Accordingly, a wide space or complicated work like a case that reproducing is executed by plural speakers is omitted and the stereophonic sound reproducing can be easily enjoyed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a three-dimensional sound reproduction device using headphones.

[Conventional technology]

Conventionally, a stereophonic sound reproduction device that performs surround reproduction etc. has a plurality of speakers (21, +31, (41, r5) arranged around a listener (1) as shown in Fig. 2, and a signal source circuit (6). ) for stereophonic sound reproduction.

For example, 3 channel audio signals a, b, c are sent to Spica (2).
~(5).

The signal source circuit (6) includes, for example, left and right input terminals C.
71) and (7r) are subjected to processing such as channel distribution 9 emphasis, delay, etc., to produce an audio signal a.
, b, c, and supply front left and right audio signals a, b to speakers (2) and +31, and rear audio signal C to speakers (41, (5)).

When , the characteristics of audio signals a, b, and c are as follows for listener (1)
and the distance between speakers (2) to (5) (2i, (3i
, (Each speaker (2) based on (45, +5f) ~ (
5) is set in consideration of the transmission characteristics of the output audio, and the output audio from the speakers (2) to (5) is transmitted to the left of the listener fil via the transmission path indicated by the broken line arrow in the figure.

By reaching the right eardrum, a highly realistic three-dimensional sound is reproduced.

In addition, C21), (3A'), (4J), (5f
) indicates the transmission path on the left ear side of the output sound of each speaker (2 to (5)), (2r).

(3r), (4r), and (5r) are speakers (2) to (5r).
) shows the transmission path on the right ear side of the output sound.

Meanwhile, the National Technical Report (Nationa
lTechnical Report) Vol, 34
120-12 of lb, 2 (published in April 1988)
"Sound field reproduction using an audible sound field simulator" on page 5 describes how to use sound field simulation processing based on architectural drawings to form a two-channel audio signal for evaluating the acoustic effects of rooms such as gymnasiums. It is described that audio signals are supplied to headphones to reproduce stereophonic sound for evaluation at the listener's position in the room.

[Problem to be solved by the invention] In the case of the device shown in FIG. 2, a plurality of speakers (2) to [5
), it requires a large space and requires complicated work such as installation and wiring of each speaker (21 to (5)).Moreover, when the surrounding area is quiet such as late at night, special glue with high soundproofing effect is required. There is a problem that it cannot be used unless it is in a room or the like, making it difficult to easily enjoy stereophonic sound reproduction of music and the like.

It is conceivable to use headphones to casually enjoy music without worrying about those around you, but the multi-channel audio signal "+h+C" cannot be played back with 2-channel headphones. , input terminals (71) and (7r) are supplied to the headphones, stereophonic sound cannot be reproduced.

Note that if a two-channel audio signal formed by the method described in the above report is supplied to headphones, it is possible to reproduce stereophonic sound using headphones, but in this case,
The complex equipment shown in Figure 2 on page 122 of the same report performs complex calculations on the audio signals recorded in the anechoic chamber, such as reverberation time simulated based on architectural data such as the room shape and materials, and correction of impulse characteristics. Since it is necessary to form a two-channel audio signal using the same method, it cannot be applied to so-called audio reproduction for consumer use.

SUMMARY OF THE INVENTION An object of the present invention is to provide a stereophonic sound reproducing device that uses multichannel audio signals for stereophonic sound reproduction using a plurality of speakers and enables stereophonic sound reproduction using headphones.

[Failure to solve the problem]

In order to achieve the above object, the stereophonic sound reproducing apparatus of the present invention, as shown in FIG.
A signal source circuit (6) that outputs Jc, and a delay circuit based on the measurement results of the listening characteristics of each of the speakers in the reproduction sound field+
8), (9),..., (14).

tIs, filter ae, C17) ,...,(
It consists of a combination circuit of 2-channel audio signals l and r for headphones (
c) a correction synthesis circuit (a) that outputs the output to the circuit;

[Effect]

In the case of the stereophonic sound reproducing apparatus configured as described above, the multi-channel audio signals a and b of the signal source circuit (6).

C is for example the output sound of the speakers (2) to (5) in Fig. 2 to the left of the listener (1).
The frequency 9 phase characteristics when reaching the right ear are corrected and synthesized to convert into two-channel audio signals l and r, and these audio signals 1. r is supplied to the headphones (to), the multi-channel audio signals a, b, c for stereophonic sound reproduction by the speakers (2) to (5) are supplied to the delay circuit (8).
)~a0. Processing is performed by a correction synthesis circuit (c) with a simple configuration combining filters 0i3) to (c), and stereophonic sound can be reproduced using headphones (c).

〔Example〕

One embodiment will be described below with reference to FIG.

In the figure, the same symbols as in Figure 2 indicate the same things,
+s), (9), 01, Ql) is the distance (21-
(Delay circuit for setting delay amount based on 51, a'2.C
3, (14), (lυ is a delay circuit for setting the transmission phase difference between the left and right ears, ae, Q7+, ..., (a)
.

(A) is a filter for frequency characteristic setting, and (C) is a filter for output correction.

(5) is delay circuit (8) ~aυ, filter 0Q-(c)
(c) is the headphone worn by the listener (1).

Then, the 3-channel audio signal a of the signal source circuit (6),
Based on b and c, the correction synthesis circuit (c) converts the transmission paths (21) and (31) from the speakers (2) to (5) in FIG.
), (G').

(A signal with synthetic characteristics of the voice that reaches the left ear of the listener (1) via 51 and a transmission path (2r) from the speakers (2) to (5).

(8r), (4r), and (5r) to form a signal with synthetic characteristics of the voice that reaches the right ear of the listener (1).

In other words, in the case of stereophonic sound reproduction using the output sounds of the speakers (2) to (5), the output sounds of the speakers (2) to (5) have a delay corresponding to the distance (21 to (51) and a direction of the sound source). It is affected by the difference in frequency two-phase characteristics at the positions of the left and right eardrums of the dependent listener (1).

On the other hand, when performing stereophonic sound reproduction using the output sound of the headphones (c), the output sound of the headphones (a) is not affected by the delay of the distance #(21 to (51) and the difference in frequency two-phase characteristics, The sound is directly transmitted to the listener's (1) left and right eardrums.

Therefore, for example, 3 channels) V audio signal a.

Three-dimensional sound cannot be reproduced by simply combining and distributing signals b and c and supplying them to headphones (c).

Therefore, when designing, etc., it is recommended to measure the listening characteristics of the speakers (2) to (5) through the left and right eardrums in the playback sound field, such as the transfer function and response characteristics described in the above report. Based on the measurement results, the transmission path on the left ear side (
2J), C31), (41), (5I) and the right ear side transmission paths (2r), (3r), (4r), and (5r), each correction amount corresponding to the frequency 1 phase characteristics is determined.

Then, based on the correction amounts corresponding to the transmission paths (2f) and (2r), the delay circuit (8) is set to a delay amount corresponding to the distance (21), and the filters 06+ and Q7 are set to the delay amount corresponding to the transmission path (2f) and (2r).
1, (2r) is set to the characteristics of the frequency transfer function when reaching both ears, and the delay circuit 02 is set to a delay amount corresponding to the transmission phase difference between the ears.

Similarly, based on the correction amount corresponding to the transmission path (a/?), (3r), the delay amount of the delay circuit (9), the filter α8)
, 09) and the delay amount of the delay circuit (131), and the transmission path (41).

Based on the correction amounts corresponding to (4r), (FV), and (5r), the delay circuit 0. (j, (Ill delay amount, characteristics of filter (20-c?:').

Set the delay amount of delay circuit 0θ.

Furthermore, filter 00. (a) and delay circuit av,
The summed signal of the output of n is input to the filter (to), and the filter Q9), (23 and delay circuit C32
, (141) is input to the filter (c), and the frequency characteristics of both the summed signals are corrected to form a two-channel audio signal 1.r.

That is, each of the above correction amounts is transmitted to the listener (1) through the eardrum.
If both summation signals are supplied as they are to the headphones (4), the output sound of the headphones (C) will become the sound with the characteristics that have already passed through the eardrum, and this sound will further pass through the eardrum. If the listener cannot reach 1), the auditory characteristics will become unnatural.

Therefore, the filters (C) and (C) are set to have the inverse characteristics of the frequency transfer function from the auditory canal to the eardrum of the listener (1), and the two added signals are corrected to the characteristics before passing through the eardrum.

Note that the above-mentioned inverse characteristic may be obtained, for example, from the average of measurement results for a large number of listeners (1).

Therefore, the audio signals a, b, and c have frequencies near the left and right eardrums of the listener (1), based on the measurement results of the listening characteristics in the reproduction sound field of the speakers (21 to r5+).

The phase characteristics are corrected and synthesized, and the signals are converted into audio signals l and r.

and headphones (g) to which the audio signals l and r are supplied.
The left and right output sounds have the characteristics when the output sounds from the speakers (2) to (5) reach the left and right ears of the listener (1), and the output sounds from the speakers (2) to (5) The same stereophonic sound reproduction as when used is performed.

Incidentally, adjustment volume for the delay amount of the delay circuits (8) to (L!51) and the frequency characteristics of the filters O. to (A) may be provided so that the characteristics can be arbitrarily adjusted during listening.

Also, is the synthesis correction circuit (a) used for headphones? It may be formed integrally with Q.

In the above embodiment, the three-channel audio signals a, b,
The characteristics of the synthesis correction circuit (A) were set based on the measurement results of the listening characteristics when reproducing C with four speakers (2) to [5), but the characteristics of the output audio signal of the signal source circuit (6) were set. The characteristics of the synthesis correction circuit (c) may be set based on the measurement results of listening characteristics when the number of channels and the number of speakers are different.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

A plurality of delay circuits (8) to (05), filters (10 to (2)
A simple correction synthesis circuit (c) formed by uniformly combining the multi-channel audio signals of the signal source circuit (6) can be used to adjust the output sounds of multiple speakers based on this audio signal to the left and right sides of the listener. It corrects and synthesizes the frequency 1 phase characteristic when it reaches the ear, forms a 2-channel audio signal for stereophonic sound reproduction, and also outputs this audio signal to headphones (c).
The multi-channel audio signals from the signal source circuit (6) can be used to reproduce stereophonic sound using the headphones (A).
Large spaces, such as when playing with multiple speakers,
To eliminate complicated work and to easily enjoy stereophonic sound reproduction of music, etc., without worrying about the surroundings.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the stereophonic sound reproducing apparatus of the present invention, and FIG. 2 is a block diagram of a conventional stereophonic sound reproducing apparatus using speakers. (1)...Listener, (2)-(5)...Speaker, (
6)... Signal source circuit, (8) to a51... Delay circuit, 06) to (c)... Filter, (20... Headphones, (5)... Correction synthesis circuit.

Claims (1)

[Claims] 1. A signal source circuit that outputs a multi-channel audio signal for stereophonic sound reproduction by a plurality of speakers, and a delay circuit based on the measurement results of the listening characteristics of each of the speakers in the reproduction sound field;
A correction synthesis circuit consisting of a combination circuit of filters, which corrects and synthesizes the multi-channel audio signal to the frequency and phase characteristics near the listener's left and right eardrums, and outputs a 2-channel audio signal for stereophonic sound reproduction to headphones. A three-dimensional sound reproduction device characterized by comprising: