JPH04225400A - Reflected sound compressing means - Google Patents

Abstract

PURPOSE:To make more optimum compression of reflected sounds and to obtain the correct result of compression. CONSTITUTION:The reflected sounds attaining the max. value are detected in a 1st reflected sound extracting means 12 and the processing of determining the reflected sound existing within the time taking the duration masking of the hearing sensation before and after this reflected sound into consideration as zero then detecting the second largest reflected sound from the remaining impulse responses and determining the reflected sound existing within the prescribed time before and after this reflected sound as zero is repeated. Further, the computation to subject the impulse responses compressed by the 1st reflected sound extracting means 12 to the integration of the respective reflected sounds existing within certain time at certain time intervals, to set the average values thereof respectively in the positions of the reflected sounds attaining the max. value within this time and to determine the other reflected sounds as zero is executed. The reflected sounds are selected in order of the larger amplitudes by as much as the required number of the reflected sounds and the other reflected sounds are determined as zero in a 2nd reflected sound extracting means 13. Further, a setting means 14 sets the reflected sounds extracted by the 2nd reflected sound extracting means 15 in a sound field varying control means 15.

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 for compressing reflected sound set in a sound field variable 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 simulation technology for halls and the like and the digitalization of audio equipment, the need for sound field control has rapidly increased. This sound field control uses a device called a variable sound field control device that creates a sound field by convolving an audio signal such as a music signal with a certain impulse response (reflected sound series). The convolution calculation in this variable sound field control device is realized by a DSP (digital signal processor) or a discrete IC, but due to the performance of current DSPs and discrete ICs, the length of the impulse response (number of reflected sounds) to be convolved is limited. There are limitations, and usually the impulse responses actually measured at famous halls or the like or the impulse responses obtained by calculations such as simulations are thinned out (compressed) and used.

A conventional reflected sound compression device for compressing the above-mentioned impulse response will be described below with reference to the drawings. FIG. 3 is a block diagram showing the configuration of a conventional reflected sound compression device. In FIG. 3, reference numeral 1 denotes a storage means, which inputs an impulse response obtained by measurement or calculation from the outside and stores it. The calculation means 2 to which this storage means 1 is connected calculates the energy of the reflected sound within a predetermined time interval from the impulse response stored in the storage means 1, and takes the average value and the maximum value of each within that time. Stand in the position of the reflected sound, and make other reflected sounds zero. The calculation means 2 is connected to the setting means 3 and the subsequent sound field variable control device 4, and the setting means 3 sets the reflected sound determined by the calculation means 2 in the sound field variable control device 4. As described above, the storage means 1, the calculation means 2, and the setting means 3 constitute a reflected sound compression device.

[0004] The operation of the above configuration will be explained below. FIG. 4 is a schematic diagram showing a reflected sound extraction method in a conventional reflected sound compression device, where A is the impulse response obtained by measurement or calculation, B is the reflected sound obtained by the calculation means 2, and C is the actual sound field. The reflected sound set in the variable control device 4 is shown. First, as shown in Figure 4A,
An impulse response measured in an actual hall or the like or an impulse response calculated by a simulation such as the acoustic ray method is stored in the storage means 1. Next, as shown in FIG. 4B, in the calculation means 2, the storage means 1
Find the energy of reflected sounds within a predetermined time interval T from the impulse responses stored in the , and set the average value at the position of the reflected sound that takes the maximum value within that time, and set the other reflected sounds to zero. Perform calculations.

[0005] Ei=1/NΣh2 k...(1)
However, i: Number of reflected sounds to be sought N: Number of reflected sounds within a certain time interval The number i shown in equation (1) is the number that allows the sound field variable control device 4 to perform convolution calculation. 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. As a result, the reflected sound shown in C in FIG. 4 is set in the sound field variable control device 4, and the huge number of reflected sounds determined by measurement and calculation can be compressed into a realizable number of reflected sounds. becomes possible.

[0006]

[Problem to be Solved by the Invention] However, in the conventional configuration described above, when compressing the original impulse response, reflected sound is extracted using only mathematical methods, so the compression result may be incorrect. I had a problem getting it.

[0007] The present invention solves the above-mentioned conventional problems, and aims to provide a reflected sound compression device that can more optimally compress reflected sound and obtain correct compression results. be.

[0008]

[Means for Solving the Problems] In order to solve the above problems, the reflected sound compression device of the present invention includes a storage means for externally inputting and storing an impulse response obtained by measurement or calculation, and a storage means for storing the impulse response obtained by measurement or calculation. The maximum value of the set impulse response is detected, the reflected sound in a predetermined time range before and after this maximum value, which is set in consideration of auditory temporal masking, is set to zero, and then the remaining impulse response is a first reflected sound extraction means that repeats a process of detecting the second largest reflected sound and zeroing out reflected sounds in a predetermined time range before and after the second largest reflected sound, until the last reflected sound;
Divide the impulse response compressed by the first reflected sound extracting means into predetermined time intervals, extract only the reflected sound with the maximum amplitude among the reflected sounds within the time period, and set the other reflected sounds to zero; A second reflected sound extracting means selects a necessary number of reflected sounds from the extracted reflected sounds in descending order of amplitude and eliminates other reflected sounds, and the reflected sounds extracted by the second reflected sound extracting means are extracted as a sound. The sound field control means for creating a sound field includes a setting means for setting the sound field.

[0009]

[Operation] With the above configuration, a limited number of reflected sounds are extracted and compressed from the impulse response in consideration of temporal masking of the auditory sense, so the reflected sounds are compressed more optimally, and the conventional mathematical method If the compression result is incorrect, such as when compression is performed using only

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a reflected sound compression device according to an embodiment of the present invention. In Figure 1,
A storage means 11 for storing an impulse response obtained by external measurement or measurement is connected to a first reflected sound extraction means 12, and the impulse response stored in the storage means 11 is input to the first reflected sound extraction means 12. First, the first reflected sound extracting means 12 detects the reflected sound that takes the maximum value, and detects the reflected sound within a certain time period before and after the reflected sound (approximately ±10 msec considering temporal masking of the auditory sense). The process of reducing the sound to zero, then detecting the second largest reflected sound from the remaining impulse responses, and similarly reducing the reflected sounds within a certain time period before and after that reflected sound to zero, is repeated until the last reflected sound. . Furthermore, the first reflected sound extraction means 1
A second reflected sound extracting means 13 connected to The reflected sound is integrated, and the average value is set at the position of the reflected sound that takes the maximum value within that time, and the other reflected sounds are set to zero.The impulse response after performing the above calculation is From the reflected sound series, select the required number of reflected sounds in descending order of amplitude, and set the other reflected sounds to zero. The setting means 14 connected to the second reflected sound extraction means 13 is connected to the sound field variable control means 15 and sets the reflected sound extracted by the second reflected sound extraction means 15 to the sound field variable control means 15. . The reflected sound compression device is configured as described above. Furthermore, the sound field variable control means 15 is configured to create a certain sound field by convolving a certain reflected sound and a music signal as an audio signal using this data.

The operation of the above configuration will be explained below. First, an impulse response obtained by external measurement or acoustic ray method simulation is stored in the storage means 11. Next, the first reflected sound extraction means 12 performs the first compression. That is, FIG. 2 shows the compression method in the first reflected sound extracting means 12, D indicates the impulse response stored in the storage means 11, and E indicates the maximum value of the impulse response detected and the data before and after that. F indicates the state in which the reflected sound in the deletion range e of a predetermined time range set in consideration of auditory successive masking is zero, and F indicates the auditory successive sound before and after the second largest reflected sound is detected. This figure shows a state in which reflected sounds within a deletion range f of a predetermined time range set in consideration of time masking are set to zero. As described above, through the processing shown in FIG. 2, the first reflected sound extraction means 12 compresses the impulse response stored in the storage means 11. Furthermore, the second reflected sound extraction means 1
3, the impulse response compressed by the first reflected sound extracting means 12 is input, this impulse response is divided into certain time intervals (approximately 50 msec), and the energy is determined by integrating the reflected sound within each time interval, Calculate the average value within each time period. Then, this average value is set at the time position at which the level of the reflected sound takes the maximum value within that time, and the levels of other reflected sounds before and after that time are set to zero. Then, the number of reflected sounds used in the sound field conversion control device 15 is selected from the reflected sounds remaining after performing the above processing in descending order of amplitude, and other reflected sounds are set to zero, and the reflected sound series is is set in the sound field conversion control device 15 by the setting means 14. The reflected sound extracted by this second reflected sound extraction means 15 is extracted using the same method as in FIG.

[0012] By doing this, the impulse response determined by measurement or calculation can be applied to the sound field variable control means 1.
According to the number of reflected sounds required by 5, it is possible to optimally compress the sound.

[0013]

As described above, according to the present invention, the first reflected sound extracting means performs compression taking auditory masking into consideration, and the second reflected sound extracting means compresses the necessary number of reflected sounds. Since it is compressed, the reflected sound can be compressed more optimally and correct compression results can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration 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 the reflected sound compression device.

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

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

[Explanation of symbols]

11. Storage means 12 First reflected sound extraction means 13 Second reflected sound extraction means 14 Setting means 15 Sound field variable control means

Claims (1)

[Claims] 1. A storage means for externally inputting and storing an impulse response obtained by measurement or calculation, and a method for detecting a maximum value of the impulse response stored and set in the storage means, and detecting a maximum value of the impulse response before and after this maximum value. , the reflected sound in a predetermined time range set in consideration of auditory temporal masking is set to zero, and then the second largest reflected sound is detected from the remaining impulse response, and the second largest reflected sound is detected before and after this second largest reflected sound. a first reflected sound extracting means that repeats a process of reducing reflected sounds in a predetermined time range to zero until the last reflected sound, and dividing the impulse response compressed by the first reflected sound extracting means into predetermined time intervals; Among the reflected sounds within that time, only the reflected sound with the maximum amplitude is extracted and the other reflected sounds are set to zero, and the necessary number of reflected sounds are selected in descending order of amplitude from the extracted reflected sounds, and the other reflected sounds are a second reflected sound extraction means that makes the reflected sound zero;
The reflected sound extracted by the second reflected sound extraction means,
A reflected sound compression device comprising: a sound field control means for creating a sound field; and a setting means for setting the sound field.