JPH04324899A - Reflected sound compressing device - Google Patents

Abstract

PURPOSE:To compress reflected sound of the limited number from impulse response obtained by measuring or gauging, utilizing auditory physiology. CONSTITUTION:The first reflected sound extraction means 6 is connected to the second reflected sound extraction means 7 and a setting means 8, and only the necessary number is compressed from the reflected sound system of impulse response, taking auditory successive masking into consideration. Then the compressed reflected sound is set in a sound field variable controller 4 by the setting means 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflected sound compression device set in a variable sound field control device for creating an arbitrary sound field in a normal room or the like.

0002

2. Description of the Related Art In recent years, with the development of hall simulation technology and the digitalization of audio equipment, the need for sound field control has rapidly increased. This sound field control uses a device called a sound field variable device that creates an arbitrary sound field by convolving (performing multiplication and addition) a music signal with a certain impulse response (also called a reflected sound series or simply reflected sound). be done. This convolution operation in a sound field variable device is realized by a DSP (digital signal processor) or a discrete IC, but due to the performance of current DSPs and ICs, the length of the impulse response to be convolved (the number of reflected sounds) There are limitations, and usually impulse responses actually measured at famous halls or the like or impulse responses obtained by calculations such as simulations are thinned out (compressed) and used.

An example of a conventional reflected sound compression device for compressing the above-mentioned impulse response will be described below with reference to the drawings.

FIG. 3 shows a block diagram of a conventional reflected sound compression device. (Fig. 3), 1 is a storage means for externally inputting and storing an impulse response obtained by measurement or calculation, and 2 is a storage means for storing reflected sound within a certain time interval from the impulse response stored in the storage means 1. Calculating means that calculates the energy and sets the average value at the position of the reflected sound that takes the maximum value within that time, and sets other reflected sounds to zero;
3 is a setting means for setting the reflected sound obtained by the calculation means 2 in the sound field variable device, 4 is a sound field variable control device, and 9 is amplified a plurality of signals processed and outputted by the sound field variable control device 4. 10 is a plurality of speaker groups that convert input electrical signals into sound, h(n) is an impulse response obtained externally, and S is a music signal.

Further, (FIG. 4) is a diagram showing the calculation method in the calculation means 2, in which (a) shows the impulse response obtained by measurement or calculation, (b) shows the reflected sound obtained by the calculation means 2, (c) shows the reflected sound actually set in the sound field variable control device 4. However, the horizontal axis is expressed as discrete time n.

[0006] In the reflected sound compression device configured as shown in FIG. h(
n) is stored in the storage means 1. Next, in the calculation means 2, from the impulse response stored in the storage means 1,
(As shown in Figure 4(a)), the energy of the reflected sound within a certain time interval T is determined, the average value is set at the position of the reflected sound that takes the maximum value within that time, and the energy of other reflected sounds is performs an operation to make it zero.

[0007] This calculation method is expressed by the formula:

[0008]

[Math 1]

[0009] The number i shown in (Equation 1) is the number of lines for which convolution calculation can be performed in the variable sound field control device 4. For example, in FIG. 4, there are five lines as shown in FIG. 4(c).

In this way, the reflected sound determined by the calculation means 2 is set in the sound field variable control device 4 by the setting means 3. This makes it possible to compress the huge number of reflected sounds obtained through measurements and calculations into a realistic number of reflected sounds. Further, in the sound field variable control device 4, a convolution calculation between the input music signal S and the set reflected sound is performed, and the result is output as sound to the outside via the amplifier group 9 and the speaker group 10. .

[0011]

[Problem to be Solved by the Invention] However, in the above configuration, there is no means to evaluate the degree of physical approximation between the original impulse response and the determined reflected sound. extracts extremely non-objective data that needs to be corrected based on human psychological scales,
There was a problem in that it had to be set to a variable sound field control device.

The present invention has been made in view of the above problems, and by extracting and compressing a limited number of reflected sounds from an impulse response obtained by measurement or calculation, taking into account the physiology of hearing, The present invention provides a reflected sound compression device that can extract reflected sound with more objectivity.

[0013]

[Means for Solving the Problems] In order to solve the above-mentioned problems, the reflected sound compression apparatus of the present invention includes a storage means for externally inputting and storing an impulse response obtained by measurement or the like;
first and second reflected sound extraction means for extracting a certain number of reflected sounds from the impulse response set in the storage means, taking into consideration auditory temporal masking; and the second reflected sound extraction means. The apparatus is equipped with a setting means for setting the reflected sound extracted by the sound field variable control device.

[0014]

[Operation] With the above configuration, the present invention extracts reflected sounds in consideration of temporal masking, which is the physiology of hearing, in the first reflected sound extraction means, and by setting this, objective data is obtained. can be set on the sound field variable device.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflected sound compression apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a reflected sound compression device according to a first embodiment of the present invention. (Figure 1
), 5 is a storage means for storing an impulse response obtained by external measurement or calculation, 6 is an input of the impulse response stored in the storage means 5,
First, the reflected sound with the maximum value is detected, taking into account temporal masking, the reflected sounds in a predetermined range before and after the reflected sound are set to zero, and then the second largest reflected sound is also taken into account, taking into account temporal masking. 7 is compressed by the first reflected sound extracting means 6. A second reflected sound extraction means selects the required number of reflected sounds from the impulse response in ascending order and eliminates other reflected sounds. This is a setting means for outputting to the variable control device 4. Components having the same functions as those shown in FIG. 3 are indicated by the same reference numerals.

The operation of the reflected sound compression device constructed as described above will be explained below with reference to FIG. 1.

First, the impulse response h obtained by external measurement or simulation such as the acoustic ray method is
'(n) is stored in the storage means 5. Next, the first reflected sound extraction means 6 performs the first compression. (FIG. 2) shows a compression method in the first reflected sound extraction means 6. (FIG. 2(a)) is the impulse response stored in the storage means 5, and (FIG. 2(b)) is the reflected sound in the range e before and after the maximum value detected, taking into account the temporal masking of the auditory sense. In the state where (Fig. 2(c)) is set to zero, the second largest reflected sound is detected, and the reflected sound in the range f (in this case, the same as e) is detected as a result of the auditory sense. The figure shows a state where it is set to zero taking masking into consideration. However, similarly to (FIG. 4), the horizontal axis is represented by discrete times n. In the first reflected sound extraction means 6, the impulse response is compressed by the processing shown in FIG. 2.

The auditory temporal masking will now be explained. Temporal masking refers to masking when a signal sound and an interfering sound are applied to the ear temporally apart. (Figure 5) is an example of the results of a psychological experiment regarding sequential masking (Elli
ot, 1962). The experimental results show that the signal tone is a pure tone with a duration of 10 msec, and the interference tone has a sound pressure level of 7.
It shows the amount of masking when white noise is 0 dB and has a duration of 50 msec. The solid line shows the result when the signal sound and the interference sound are applied to both ears, and the wavy line shows the result when they are applied to the opposite ear. Further, retrograde behavior refers to the case where the interfering sound is given first and then the signal sound, and forward direction is the result when the interfering sound is given after the signal sound.

In this embodiment, since the conditions are different from the above experimental results, the amount of attenuation of the reflected sound before and after is determined with reference to the experimental results. In this embodiment, a method is used in which a certain time range (10 msec) is determined and the reflected sound within that time range is set to zero.

Next, the second reflected sound extraction means 7 inputs the impulse response compressed by the first reflected sound extraction means 6, and from this impulse response, the reflected sound used in the sound field variable control device 4 is extracted. The setting means 8 sets the reflected sound series in the sound field variable control device 4, with the other reflected sounds set to zero. By doing so, it becomes possible to compress the impulse response obtained by measurement or calculation into the number of reflected sounds required by the variable sound field control device 4. Further, in the sound field variable control device 4, a convolution calculation between the input music signal S and the set reflected sound is performed, and the amplifier group 9 and the speaker group 1
0 and is output as sound to the outside.

[0022]

As described above, the present invention extracts reflected sounds in consideration of temporal masking, which is the physiology of hearing, in the first reflected sound extraction means, and transmits the reflected sounds to a sound field variable control device. By setting this, it becomes possible to compress the impulse response from the impulse response obtained by measurement or calculation, etc., by optimally collecting the required number of reflected sounds and using it as objective data.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a reflected sound compression device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a reflected sound extraction method in a first reflected sound extraction means in an embodiment of the present invention.

FIG. 3 is a block diagram of a conventional reflected sound compression device.

FIG. 4 is a schematic diagram showing a reflected sound extraction method in a conventional reflected sound compression device.

FIG. 5 is a diagram showing the results of a psychological experiment on temporal masking.

[Explanation of symbols]

5. Storage means 6 First reflected sound extraction means 7 Second reflected sound extraction means 8 Setting means 4. Sound field variable control device 9 Amplifier group 10 Speaker group

Claims (1)

[Claims] 1. Storage means for externally inputting and storing an impulse response obtained by measurement or calculation, and detecting a reflected sound having a maximum value from the impulse response stored in the storage means, Taking time masking into consideration, the amplitude of the reflected sound in a predetermined range before and after the reflected sound is attenuated, then the second largest reflected sound is detected, and the amplitude of the reflected sound before and after the reflected sound is similarly taken into consideration. a first reflected sound extracting means that repeats a process of attenuating the amplitude of reflected sounds within a predetermined range until the last reflected sound; and a necessary number of reflected sounds from the impulse response compressed by the first reflected sound extracting means. a second reflected sound extracting means which selects in descending order of amplitude and other reflected sounds are set to zero, and the impulse response extracted by the second reflected sound extracting means is combined with the set impulse response and the input music. 1. A reflected sound compression device comprising: setting means for setting a sound field control device that creates a certain sound field by processing a signal.