JPH0455038B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for measuring acoustic characteristics, and in particular to measuring acoustic transfer characteristics between a plurality of sound sources corresponding to a plurality of channels and a listening point that listens to sound reproduced from these sound sources. Regarding how to.

BACKGROUND ART Conventionally, as a method of measuring acoustic transfer characteristics in a sound field created by reproduced sounds from multiple sound sources, one microphone is set up at a listening point, and the distance difference between the microphone and the multiple sound sources is measured. In order to prevent disturbances in the sound pressure frequency characteristics, a method has generally been adopted in which a plurality of sound sources are sequentially driven individually and the acoustic transfer characteristics of each sound source at the listening point are measured.

In this measurement method, (1) when a person enters a sound field, the sound field is disturbed by the sound absorption coefficient of clothing, etc., but this influence cannot be measured;

(2) It is difficult to comprehensively evaluate a sound field that includes multiple sound sources.

(3) Comprehensive measurement results that take into account various human interaural effects, such as direction sense, interaural summation effects, etc., cannot be obtained.

There were drawbacks such as: In order to compensate for the drawback of (1) above,
It is effective to use a dummy head with microphones attached to both ears, but the dummy head has a directional characteristic that changes complexly depending on the frequency and a size that is comparable to the wavelength of the audible frequency sound wave. Because he has a right ear, it is difficult to accurately evaluate the sound field using the conventional method of driving multiple sound sources one by one independently.

Summary of the invention The present invention has been made in view of the above points, and
The purpose of the present invention is to provide an acoustic characteristic measurement method that allows accurate sound field evaluation.

The acoustic characteristic measurement method according to the present invention uses uncorrelated random noise or pseudo-random noise between a plurality of channels as a source signal for driving a plurality of sound sources, and each output of a microphone in both ears of a dummy head placed at a listening point. The method is characterized in that the received sound output characteristic at the listening point is obtained by averaging the signals, and the acoustic transfer characteristic between the sound source and the listening point is measured based on this received sound output characteristic.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings.

In the figure, a pair of front left and right speakers 1L, 1R and a rear left and right pair of speakers 2 are installed in a predetermined room.
L and 2R are arranged as sound sources, and a dummy head 4 with microphones 3L and 3R attached to both ears is arranged at a listening point where the reproduced sounds from these four channels of speakers are heard. Noise generators 6 to 9 are provided to independently drive the four-channel speakers 1L, 1R, 2L, and 2R, and random noise such as white noise ( or pseudorandom noise) becomes a source signal for each speaker 1L, 1R, 2L, 2R via amplifiers 10 to 13, respectively.

In this way, by using uncorrelated random noise between each channel as the source signal,
Even if all speakers in the sound field are driven simultaneously, microphones 3L, 3R and speakers 1L, 1R, 2
This means that the sound pressure frequency characteristics are not disturbed due to the distance difference between L and 2R, and a sound field including a plurality of sound sources can be comprehensively evaluated.

Microphones 3L and 3 on both ears of dummy head 4
The R output signals are added together by an adder 14 and supplied to an analyzer 15. The received sound output characteristic at the listening point is obtained by averaging the added output of the adder 14. For example, the acoustic transfer characteristic between the sound source (speaker) and the listening point (dummy head) can be measured based on the difference between the received sound output characteristic and the transfer characteristic before the sound source.

In this way, by using the dummy head 4 and measuring the characteristics based on the average of the respective output signals of the microphones 3L and 3R of both ears, the sound field can be represented by one transfer function. Here, if the difference in characteristics between the left channel and the right channel is large, a binaural effect will occur, making it somewhat difficult to evaluate in terms of sense of direction, etc., but a characteristic difference of 3 to 6 dB in a narrow frequency range will result in a binaural effect. Therefore, when there is not much difference in the characteristics of the left and right ears, it can be said that the evaluation method using the average of the microphones 3L and 3R of both ears is effective.

Effects As explained above, according to the present invention, uncorrelated random noise (or pseudorandom noise) is used between each channel as a source signal for driving a plurality of sound sources, so that all sound sources in the sound field are Since they can be driven and measured simultaneously, it is possible to comprehensively evaluate the acoustic characteristics in a sound field that includes multiple sound sources.

In addition, since the characteristics were measured based on the summed output of each output signal from the microphones in both ears of the dummy head, comprehensive measurement results were obtained that took into account the human sense of direction between both ears, the summation effect, etc. It will be done.

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. Explanation of symbols of main parts, 1L, 1R, 2L, 2
R...Speaker, 3L, 3R...Microphone, 4...
Dummy head, 6 to 9... Noise generator, 14... Adder, 15... Analyzer.

Claims (1)

[Claims] 1. A dummy head with microphones attached to both ears is placed at a listening point where reproduced sounds from multiple sound sources corresponding to multiple channels are heard, and a dummy head with microphones attached to both ears is placed between the sound source and the listening point based on the output of the microphone. A measurement method for measuring the acoustic transfer characteristics of a sound source, wherein uncorrelated random noise or pseudorandom noise is used between a plurality of channels as a source signal for driving the plurality of sound sources, and each output of the microphones in both ears of the dummy head is Acoustic characteristics characterized in that a received sound output characteristic at the listening point is obtained by averaging signals, and an acoustic transfer characteristic between the sound source and the listening point is measured based on the received sound output characteristic. Measuring method.