JPH08202392A - Reverberation adding method and device therefor - Google Patents

Abstract

PURPOSE: To change a reverberation time frequency characteristic of reverberation added based on impulse response measured in a sound field to a desired value. CONSTITUTION: After reverberation signals of N pieces obtained by dividing into N pieces on a time base by FIR filters 12-14 of N pieces are passed through amplifiers 15-17 and tone control filters 18-20, based on delay times of each pulse extracted from impulse response measured in a sound field for a signal from an arbitrary signal source 11, they are divided into M bands by band pass filters 21-24 of M bands respectively. And a reverberation time frequency characteristic of a signal is changed by stages by controlling with controller 31 so that amplification factors in amplifiers 25-28 are different for each time window when only one band out of M bands is remarked in output for each band.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for adding reverberation using an impulse response measured in a sound field.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram showing the structure of a conventional reverberation sound adding device. In FIG. 2, 101 is a signal source such as music, and 102 to 104 are signal sources 10.
It is an FIR filter that changes the signal from 1 to a desired characteristic. 105 to 107 are FIR filters 102 to 10
An amplifier for amplifying the signal having the desired characteristics in 4.
To 110 are tone color control filters for changing the tone colors of the signals amplified by the amplifiers 105 to 107, 111 is an adder for adding the outputs of the tone color control filters 108 to 110, 112
Is a controller for controlling the amplification factor of the amplifiers 105 to 107, 1
13 is an amplifier for amplifying the output of the adder 111, 114 is a speaker connected to the amplifier 113, 115 is a listener,
Reference numeral 116 is a reproduction sound field in which a speaker 114 is arranged and forms a desired sound field, and forms an optimum sound field in both ears of the listener 115.

Next, the operation of the reverberation adding apparatus according to the above-mentioned conventional example will be described with reference to FIG. The FIR filters 102 to 104 are configured to give the same reverberation characteristic to the input signal based on the impulse response measured in a sound field desired to be reproduced in a theater, for example. That is, the signals output from the signal source 101 are convolved in the FIR filters 102 to 104, and reverberation sounds are added. The outputs of the FIR filters 102 to 104 are amplified by the amplifiers 105 to 107 and the reverberation time is changed. The tone color of the output signals of the amplifiers 105 to 107 is controlled by the tone color control filters 108 to 110. The outputs of the tone color control filters 108 to 110 are added by an adder 111, amplified by an amplifier 113, and then supplied to a speaker 114 in a reproduced sound field 116. In the reproduction sound field 116, the listener 115 listens to the sound waves emitted from the speaker 114. In this way,
Even in the past, using the measured impulse response,
The reverberation time can be changed for the input signal.

[0004]

However, in the above conventional reverberation sound adding device, although the reverberation time can be changed, there is a problem that it cannot be changed even when the reverberation time frequency characteristic is desired to be changed. It was

The present invention is intended to solve such a conventional problem, and it is possible to change the reverberation time to a desired value by using an impulse response measured in a sound field, and at the same time, An object of the present invention is to provide an excellent reverberation sound adding method and device capable of changing frequency characteristics.

[0006]

In order to achieve the above object, the present invention provides N pieces obtained by dividing the impulse response measured in advance into N on the time axis based on the delay time of each pulse. The reverberation sound signal of is divided into M bands, and when only one band in the M band is focused on the output of each band, the amplification factor is controlled so as to be different depending on the time window. The reverberation time frequency characteristic can be changed.

The present invention also divides a signal from an arbitrary signal source into N pieces by dividing them on the time axis based on the delay time of each pulse extracted from the impulse response measured in the sound field. N FIR filters that generate reverberation sound signals, N amplifiers that individually amplify the N reverberation sound signals, and a first controller that individually controls the amplification factors of the N amplifiers, N tone color control filters connected to the outputs of the N amplifiers, M band division filters connected to the outputs of the N tone color control filters, and M output of the M band division filters. Amplifiers for individually amplifying each reverberation signal, a second controller for individually controlling the amplification factors of the M amplifiers, an adder for adding the outputs of the M amplifiers, and Equipped with an amplifier that amplifies the output of the instrument and outputs it to the speaker Those were were.

[0008]

According to the present invention, according to the above configuration, the reverberation time of the reverberation sound added to the input signal can be changed to obtain a desired reverberation sound, and the timbre can be controlled individually. The desired reverberation sound frequency characteristic can be obtained by changing the reverberation time frequency characteristic of the signal stepwise.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIG. FIG. 1 is a block diagram showing the configuration of a reverberation sound adding device according to an embodiment of the present invention. In FIG.
Reference numeral 11 is a signal source such as music. Reference numerals 12 to 14 denote N FIR filters that generate N reverberation sound signals by dividing the time division into N on the time axis based on the delay time of each pulse extracted from the impulse response measured in the sound field. Reference numerals 15 to 17 denote N first amplifiers A for individually amplifying N reverberation sound signals, and 30 denotes N amplifiers 15 to 1
7 is a first controller A for individually controlling the amplification factor of 7. 1
8 to 20 are N tone color control filters connected to the outputs of N amplifiers 15 to 17, and 21 to 24 are M tone bands connected to the outputs of the N tone color control filters 18 to 20, respectively. It is a division filter. 25 to 28 is M
The number M of second amplifiers B that individually amplifies the number M of reverberation sound signals that are the outputs of the number of band division filters 21 to 24, and 31 is the amplification factor of each of the number M of amplifiers 25 to 28. It is the second controller B for controlling. 29 is each time window 3
9 to 41 are adders that add the outputs of the M amplifiers 25 to 28, 32 is an amplifier that amplifies the output of the adder 29 and outputs it to the speaker 33, 34 is a listener,
Reference numeral 35 is a reproduced sound field. In addition, the M band-splitting filters 21 to 24 and the M amplifiers 25 to 28 respectively make M
The individual reverberation time frequency characteristic changing units 36 to 38 are configured.

As will be described later, the characteristics of each of the FIR filters 12 to 14 are changed so that they have different reverberation times based on the impulse response in the sound field desired to be reproduced. Further, the amplifiers A15 to 17 are connected to the outputs of the respective FIR filters 12 to 14, and the amplification factors can be independently changed under the control of the first controller A30. Therefore, the reverberation time can be changed by changing the amplification factor of the amplifier A according to the time window. The outputs of the amplifiers A15 to 17 are connected to the tone color control filters 18 to 20, and the tone colors are individually controlled.

The j-th band division filter and the second amplifier B in the i-th time window can be generally expressed as the band division filter [i, j] and the amplifier B [i, j], and the amplifier B
The reverberation time frequency characteristic can be changed by independently controlling the amplification factor of [i, j] by the second controller B31 so that a desired reverberation time frequency characteristic can be obtained.

All the outputs of the amplifier B in the reverberation time frequency characteristic changing units 36 to 38 are added by the adder 29 and further amplified by the amplifier 32 to a desired size. The output of the amplifier 32 is supplied to the speaker 33 of the reproduced sound field 35. In the reproduction sound field, the listener 34 listens to the sound waves emitted from the speaker 33.

Next, the operation of the above embodiment will be described in more detail. In FIG. 1, the output signal from the signal source 11 is input to N FIR filters 12 to 14, and each reverberation time characteristic of each FIR filter 12 to 14 is an actual sound field, as described below. It is obtained from the pulse train extracted from the measured impulse response.

The pulse train may be extracted by, for example, a known inverse filter process, a method of selecting pulse trains in descending order of amplitude, or a method of detecting the maximum amplitude while performing masking. Good. The pulse train density needs to be 200 taps or more per 100 ms.

Next, a method of generating the FIR filter will be described. The pulse train obtained by the above method is divided for each duration TW of the time window and assigned to each of the N FIR filters so that each of the N filters produces a reverberation time equivalent to that of each, that is, a reverberation sound. Composed.
The time window TW may be set to 100 ms or less.
In this way, the outputs of the respective FIR filters 12 to 14 having different reverberation times are input to the amplifiers A15 to 17, respectively.

Here, assuming that the reverberation time of the pulse train is RTp and the desired reverberation time is RTd (where RTp> RT
d), the amplifier A [i] (i = 1, 2, 3, 4, ...
The amplification factor α [i] set in N) is calculated by the following equation (Equation 1).

[0017]

[Equation 1]

The tone colors of the outputs of the amplifiers A15 to 17 are controlled by tone color control filters 18 to 20. The characteristics of the timbre control filter [i] (i = 1, 2, 3, 4, ..., N) have a desired reverberation time frequency RT (f) (f is a frequency).
Therefore, the power spectrum p [f, i] obtained by the following equation (Equation 2) is approximated.

[0019]

[Equation 2]

The j-th band-splitting filter and the amplifier B in the i-th time window are generally the band-splitting filters [i,
j] and an amplifier B [i, j]. RTc here
Let [j] be the coefficient for which RTd is to be changed in that band (multiplying RTd by RTc [j] will give the reverberation time of that band), and amplification factor β [i, j] is calculated by the following equation (Equation 3).

[0021]

(Equation 3)

All outputs of the amplifier B in the reverberation time frequency characteristic changing units 36 to 38 are added by the adder 29 and further amplified by the amplifier 32 to a desired size. The output of the amplifier 32 is supplied to the speaker 33 of the reproduced sound field 35. In the reproduction sound field, the sound wave radiated from the speaker 33 is received by the listener 34.
To listen.

Thus, according to this embodiment, the amplifier B
The reverberation time frequency characteristic can be changed by independently controlling the amplification factor of [i, j] by the controller B so as to obtain a desired reverberation time frequency characteristic.

The band-splitting filter in this embodiment can be basically composed of two components, a low-pass filter and a high-pass filter. It may be composed of three, may be composed of a low-pass filter, a plurality of band-pass filters and a high-pass filter, or may be composed of only a plurality of band-pass filters. Further, the above band division filter may be configured with a 1/3 octave band or 1 octave band.

[0025]

As is apparent from the above description, the present invention provides N reverberation sounds obtained by dividing the impulse response measured in advance into N on the time axis based on the delay time of each pulse. The signals are divided into M bands, and when only one of the M bands is focused on the output of each band, the amplification factor is controlled to be different depending on the time window. The time can be changed to a desired value, the reverberation time frequency characteristic can be changed, and a desired sound field can be reproduced in a wide range.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a reverberation sound adding device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional reverberation sound adding device.

[Explanation of symbols]

 11 signal source 12 FIR filter (1) 13 FIR filter (2) 14 FIR filter (N) 15 amplifier A (1) 16 amplifier A (2) 17 amplifier A (N) 18 tone color control filter (1) 19 tone color control filter (2) 20 tone color control filter (N) 21 band division filter (1) 22 band division filter (2) 23 band division filter (M-1) 24 band division filter (M) 25 amplifier B (1) 26 amplifier B ( 2) 27 amplifier B (M-1) 28 amplifier B (M) 29 adder 30 controller A 31 controller B 32 amplifier 33 speaker 34 listener 35 reproduced sound field 36 reverberation time frequency characteristic changing unit (1) 37 Reverberation time frequency characteristic changing unit (2) 38 Reverberation time frequency characteristic changing unit (N) 39 Time window (1) 40 time window (2) 41 time window (N)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G10K 15/00 // H03H 17/08 8842-5J

Claims (2)

[Claims] 1. N reverberation sound signals obtained by dividing the pre-measured impulse response into N on the time axis based on the delay time of each pulse are divided into M bands, and each band is divided into M bands. The reverberation sound addition method in which the reverberation time frequency characteristic of the signal can be changed stepwise by controlling the amplification factors to be different depending on the time windows when paying attention to only one band in the output M band. 2. N reverberation sound signals obtained by dividing a signal from an arbitrary signal source into N on a time axis based on a delay time of each pulse extracted from an impulse response measured in a sound field. N FIR filters, N amplifiers for individually amplifying the N reverberation sound signals, and N
A first controller for individually controlling the amplification factor of each amplifier;
N tone color control filters connected to the outputs of the N amplifiers, M band division filters respectively connected to the outputs of the N tone color control filters, and outputs of the M band division filters , M amplifiers for individually amplifying the M reverberation signals, a second controller for individually controlling the amplification factors of the M amplifiers, and outputs of the M amplifiers are added. A reverberation sound adding device comprising an adder and an amplifier for amplifying the output of the adder and outputting the amplified output to a speaker.