JPH03268699A - Sound field reproducing method using compressed sound field information - Google Patents

Abstract

PURPOSE:To reproduce impression of a sound field even with less information quantity by compressing information of an impulse response measured by a dummy head microphone through the use of a time series inter-ear correlation. CONSTITUTION:An impulse signal from a generator 2 radiates from a speaker 4 at a position of a sound source in a reproduction sound source 1. A dummy head microphone 5 placed at a listening position measures an impulse response at a position corresponding to left and right ears and sends the result to a time series inter-ear correlation counter 6. The counter 6 calculates a time series inter-ear correlation function RCC of a time window to obtain a time maximizing the RCC in each block, an azimuth angle making an inter-ear time difference equal, a time maximizing a sound pressure in each block and energy in each block, and each information is sent to a convolution computing element 9. A sound signal from a signal source 8 is fed to the computing element 9. Then the signal is sounded at a prescribed speaker 11 in an optional space 7.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a sound field reproduction method using compressed sound field information for reproducing another sound field in an arbitrary space.

BACKGROUND OF THE INVENTION Conventionally, this type of sound field reproduction method is configured to reduce the amount of information in a sound field by selecting one with larger energy than the measured impulse response of the sound field. This is a method that attempts to physically reproduce the impulse response, and if the degree of information compression is low and there is a sufficient amount of information, it is possible to reproduce the impression of a sound field.

Problems to be Solved by the Invention However, the conventional sound field reproduction method described above has a problem in that when the degree of compression is high and the amount of information is reduced, the ability to create a sound field impression is reduced. The present invention is intended to solve these conventional problems, and it is an object of the present invention to provide a sound field reproduction method that can reproduce the impression of a sound field even with a high degree of compression and a small amount of information.

Means for Solving the Problems In order to achieve the above object, the present invention compresses sound field information measured at the left and right ears of a dummy head microphone using a time-series binaural cross-correlation function. This is what I did.

Therefore, according to the present invention, by compressing the impulse response measured with a dummy head microphone using time-series interaural cross-correlation, it is possible to reproduce the impression of a sound field even with a small amount of information. have

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention. In FIG. 1, l is the sound field to be reproduced. 2 is an impulse generator, which is connected to the amplifier 3 at t#We. 4 is a speaker that emits an impulse response. 5 is a dummy head microphone, which picks up one impulse at positions corresponding to the left ear and right ear, respectively. 6
is a time-series inter-aural cross-correlation function measuring instrument, which calculates a time-series inter-aural cross-correlation function from the impulse responses at the left and right microphones of the dummy head microphone 5.

7 is an arbitrary space in which a sound field is reproduced. 8 is an audio signal source, which is connected to a convolution calculator 9;

It is a 10Fi amplifier and is connected to the speaker 11. 12 is a listener.

Operation Next, the operation of the above embodiment will be explained. First, in the sound field 1 to be reproduced, the impulse generated by the impulse generator 2 is amplified by the total amplifier 3, and then radiated by the speaker 4 installed at the sound source position, and then radiated by the dummy head microphone installed at the listening position. 5, the impulse responses at positions corresponding to the left and right ears are measured and output to the time-series inter-cochlear cross-correlation function measuring instrument 6.The impulse responses at positions corresponding to the left and right ears are measured as hNtl and hr, respectively. (tl) The time-series interaural cross-correlation function measuring device 6 calculates the time-series interaural cross-correlation function RCC(i, τ) of the i-th time window using the following equation.

RCC(i,T)=fTwhl(i-1)4”W+t
) ・hr((i-1) ・TW+t+r) dt
/[7Twhl”((i-1) ・TW-1-t)d
t ・/”Twhr2((i-1)・TW+t)dtl
``'(1)(t) Here, the time window TW is 5 to 10 m5, and the interaural time difference τ is -1 to +1 ms.

Also, find the time τ(if) at which the RCC of each section is maximum and the azimuth angle ψ(il) at which the interaural time difference is equal to τ(if). From the impulse response at the position, RC'
The time △t(i
Find t. Furthermore, the energy E(il'
ff: Calculated using Equation 2.

E(il=6-1og2(2""+2Lr/6)
(21) Ll and Lr are the sound pressure levels at positions corresponding to the left ear and right ear of the dummy heated microphone 5 in each section, respectively.

Each time delay Δt (
The information of il, energy E(it, azimuth ψ(it) is input to the convolution calculator 9.

The audio signal output from the audio signal source 8 is subjected to a convolution operation by a convolution calculator 9, and after being amplified by an amplifier 10,
Among the speakers 11 surrounding the listener 12 in an arbitrary space 7, it is presented with a time delay Δt(it, energy E(it) from a speaker in a subspace including the azimuth angle ψ(il).

Effects As described above, according to the above embodiment, the impulse response at the positions corresponding to the left and right ears of the dummy Hepto microphone 5 installed at the listening position is measured by the time-series inter-cochlear cross-correlation function measuring device 6. By compressing, less information W
It has the advantage of being able to reproduce the impression of a sound field.

Effects of the Invention As is clear from the above embodiments, the present invention measures the impulse response of a sound field using a dummy head microphone, and further compresses the information into a time-series inter-ear cross-correlation function.
It has the advantage of being able to reproduce the impression of a sound field in any space with a small amount of information.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a configuration used in a sound field reproduction method using compressed sound field information in an embodiment of the present invention. 1...Sound field, 2...Impulse generator, 3...Amplifier, 4...Speaker 5...Dummy head microphone, 6...Katsu series binaural cross-correlation function measuring device, 7...
...Arbitrary space, 8...Audio signal source, 9...Convolution operator, lO...Amplifier, 11...Speaker 1
2...listener.

Claims (1)

[Claims] By measuring the impulse response of a sound field with a dummy head microphone and compressing the sound field information using a time-series interaural cross-correlation function, the impression of the sound field can be expressed in any other space with a small amount of information. A sound field reproduction method using compressed sound field information to be reproduced.