JPH096392A - Speech speed conversion device and its utilization - Google Patents

Abstract

PURPOSE: To continuously convert the speech speed of reproduced speech for a long period of time without being interrupted by the limit of memory capacity by controlling reproducing operation of a recording/reproducing device according to the capacity of the voice data stored in a memory in the inside of a speech speed conversion device. CONSTITUTION: The speech speed is converted by the speech speed conversion device 100 connected to the recording/reproducing device 200. The result performing speech speed conversion processing for an inputted speech signal is outputted at a sampling interval while recording it in a buffer memory in the inside of the speech speed conversion device 100. Thus, the voice data of a length equivalent to a time difference between input/output voices are stored in the memory inside the speech speed conversion device 100. A control signal generation means acts so as to stop temporarily the reproducing operation of the recording/reproducing device 200 when stored voice data capacity becomes nearly equal to memory capacity. Then, the voice stored in the memory is outputted any time, and when a sufficient free area occurs in the memory, the reproducing operation of the recording/reproducing device 200 is performed again.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice speed conversion device which is a digital voice signal processing device for converting speed without changing the pitch of voice, and particularly for use in connection with a recording / reproducing device such as a tape recorder. Pertaining to the method.

[0002]

2. Description of the Related Art In recent years, attempts have been made to perform hearing aid over the entire auditory system including a decline in language processing speed by changing only speed without changing pitch of voice by digital signal processing. For such a speech speed conversion technology, for example, a collection of lectures of the Acoustical Society of Japan (March 1994, 2-
4-7) "Evaluation of speech speed conversion speech by hearing-impaired people" and the Journal of Acoustical Society of Japan (Vol. 50, No. 7, 1994, P509 to P520) "Real-time speech speed conversion type listening system". In particular, recently, a portable speech speed conversion device has been developed in which this speech speed conversion function is housed in a portable-sized device. For this device, refer to "A portable digital speech-rate converte
r and its evaluation by hearing-impairedlistener
s ", in Proc. of Int. Conf. on Spoken Language Pro
cessing (ICSLP94,) pp.2055-2058, Yokohama, Sep.
1994.

FIG. 8 shows the operation of this conventional speech speed conversion apparatus. In the conventional speech rate converter, first, the input voice signal is converted into a digital value by the A / D conversion means 10. The digitized voice is alternately input to two input buffers 30 having a fixed time length (hereinafter referred to as a frame). While inputting to one input frame buffer, speech speed conversion processing 40 is performed that expands or contracts the audio time axis of the audio data of the other input frame buffer that has already been input without changing its pitch. Give. Then, the processing result is recorded in the output ring buffer 50.
The output ring buffer 50 is a memory whose addresses are circularly used so that the end address is followed by the start address. Output ring buffer 50 to 1 independently of writing the speech speed conversion processing result to output ring buffer 50
By taking out the processed data one by one and outputting the audio signal through the D / A conversion means 60 at the same time,
The speech speed conversion processing and the output of the conversion result proceed at the same time, and real-time speech speed conversion is realized. Therefore, the output voice is output with a delay time with respect to the input voice, and the delay time spreads with time. That is, the listener can listen to the voice slowly, but slowly behind the reality. This speech speed conversion operation is controlled by the user through the slow button 160 provided on the device, the speech speed conversion is performed while the slow button is pressed, and the speech speed conversion is not performed when the slow button is not pressed. Instead, the input voice is output as it is. In FIG. 8, this operation is represented by the switch means 20 controlled by the slow button. The above operation is realized by the device configuration shown in FIG. The speech speed conversion processing shown in FIG. 8 is realized by software operating on the microprocessor 110. Further, the input buffer 30 and the output ring buffer 50 shown in FIG. 8 are secured in the external RAM 120 connected to the processor, and the configuration of FIG. 8 is realized by address control in the program. The control information from the slow button 160 is given through the control circuit 130 and the I / O circuit 112 on the microprocessor, and the above-described switch operation is realized by software. Note that in FIG. 9, the A / D converter 111 and the D / A converter 114 are also provided inside the microprocessor, and the operation thereof is also controlled to be performed by a program. And the software is a microprocessor
It is stored as a program in the ROM 115 inside the 110.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention
Without changing the pitch of the voice, that is, the pitch of the voice,
This is useful for learning and training foreign languages, because the voice can be played only slowly. In actual language learning, voices recorded on tapes are often used as teaching materials.

However, in the above-mentioned conventional apparatus, a speech speed converting apparatus is connected to a recording / reproducing apparatus such as a tape recorder to consider means necessary for converting a speech speed of a long voice without interruption. Was not done. That is, in the above-described conventional voice speed conversion device, the voice after the voice speed conversion is output while being recorded in the memory, thereby slowly converting the voice while expanding the time delay from the input voice. For this reason, there is a problem that voice information of a length corresponding to the time difference between input and output is always recorded in the memory, and when the time difference exceeds the memory capacity, the voice speed cannot be continuously converted. .

An object of the present invention is to connect a speech speed conversion device to a recording / reproducing device such as a tape recorder, and to continuously convert the speech speed of recording / reproducing sound for a long time without interruption due to the limitation of the memory capacity. To provide the means.

[0007]

SUMMARY OF THE INVENTION The above-mentioned object is to convert a voice speed by taking in an input voice from a recording / reproducing device, expanding a time axis without changing a pitch of the input voice, and outputting a voice whose voice speed is converted. The device is achieved by a voice speed conversion device having a control signal generating means for controlling the reproduction operation of the recording / reproducing device.

The control signal generating means is configured to control the reproducing and pausing operations of the recording / reproducing apparatus according to the capacity of the voice data stored in the memory inside the speech speed converting apparatus.

In the present invention, the control signal for controlling the reproducing operation of the recording / reproducing apparatus is output in accordance with the amount of voice data accumulated in the memory means inside the speech rate converting apparatus in association with the speech rate converting process. To be done.

On the other hand, the speech speed conversion apparatus of the present invention is a speech expansion / contraction unit that expands / contracts the time length of an audio signal in frame units, an A / D conversion unit, an input buffer composed of a plurality of frame buffers, and a frame unit. A speed conversion processing means, an output buffer having a ring buffer configuration in which addresses are used in a ring,
A monitoring means comprising D / A conversion means, and monitoring the amount of audio data accumulated in the output ring buffer,
Control signal generating means for generating a control signal for controlling the reproducing operation of the recording / reproducing means, wherein the monitoring means corresponds to the audio data amount accumulated in the output buffer, and the A / D conversion is performed. The operation of the means and the operation of the control signal generating means are controlled.

Further, the speech speed conversion apparatus of the present invention comprises A / D conversion means, an input buffer having a ring buffer structure in which addresses are circularly used, and reproduction address control means for controlling a read address from the input buffer. A voice speed conversion processing means for expanding and contracting the time length of a voice signal in frame units without changing the pitch, an output buffer composed of a plurality of frame buffers, and a D / A conversion means, and the input ring The input buffer has a monitoring means for monitoring the amount of audio data accumulated in the buffer, and a control signal generating means for generating a control signal for controlling the reproducing operation of the recording / reproducing apparatus. The operation of the A / D conversion means and the operation of the control signal generation means are controlled according to the amount of audio data to be stored.

In the control by the monitoring means, when the amount of voice data accumulated in the input or output ring buffer approaches the maximum amount that can be held in the input or output ring buffer, the reproduction of the recording / reproducing apparatus and the A / D conversion are performed. When the operation of the converting means is temporarily stopped, the voice speed converting process is continued, and the accumulated voice data is output. When the amount of voice data accumulated in the input or output buffer approaches 0, the reproduction of the recording / reproducing apparatus is performed again. The operation and the operation of the A / D conversion means are started.

At this time, the speech speed conversion device has a repeat function of repeatedly reproducing the past voice, and when the repeat function is executed, the monitoring means causes the recording / reproducing device and the A / D conversion means. By temporarily stopping the operation of, the new input voice data is prevented from entering the input ring buffer during the repeat operation.

In the present invention, the control signal for controlling the operation of the recording / reproducing apparatus is a wireless remote control signal.

The speech speed converter of the present invention comprises a low-pass filter for the purpose of anti-aliasing at the input and output of an analog audio signal, an A / D converter, and a D / D converter.
A / A converter, a microprocessor, an external memory, a control button, and a control circuit for inputting the state of the control button to the microprocessor, and control for controlling the recording / playback apparatus. The series of operations described above is realized by a software program which has a means for generating a signal and is on the microprocessor.

Furthermore, in the method of using the present invention, a recording / reproducing apparatus having two output channels reproduces audio, outputs the same audio signal from both of the two output channels, and provides two separate inputs. In a system for duplicating and recording a voice by a recording / reproducing device having a channel, a voice speed for executing a voice speed conversion process for expanding / contracting a time length of a voice signal without changing a pitch of a voice signal between signal paths of one channel. There is also a method of using a speech speed conversion device in which a conversion device is provided and only one channel voice is subjected to a voice speed conversion process and recorded, and a normal speed voice is recorded in the other channel.

[0017]

[0018]

According to the present invention, the voice speed is converted by the speech speed conversion device connected to the recording / reproducing device. Inside the speech speed conversion device, while recording the result of performing the speech speed conversion process on the input voice signal in the buffer memory,
Simultaneously output at sampling intervals. As a result, voice data having a length corresponding to the time difference between the input and output voices is accumulated in the memory inside the speech speed conversion device. The control signal generating means acts to temporarily stop the reproducing operation of the recording / reproducing apparatus when the accumulated audio data capacity becomes substantially equal to the memory capacity. Then, the sound accumulated in the memory is output at any time, and when the memory has a sufficient empty area, the recording / reproducing apparatus performs the reproducing operation again. As a result, when the speech speed conversion device is connected to the recording / reproducing apparatus and used, the speech speed conversion function can be continuously used for a long time regardless of the memory capacity.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments.

FIG. 1 is a block diagram of the first embodiment of the present invention. In this embodiment, the recording / reproducing apparatus 200 has a function of reproducing the sound of a recording medium such as a CD or a cassette tape recorder. Furthermore, the above recording / playback device 2
00 has a function for controlling its operation by a remote control signal such as infrared rays given from the outside.

Further, in the speech speed conversion apparatus 100 of this embodiment, an external input terminal is prepared in addition to the microphone 101, and the audio output of the recording / playback apparatus is input through this external input terminal. There is. The input audio signal is processed by the analog amplifier 102 and the low pass filter 1
Given to the microprocessor 110 through 03. In the microprocessor 110, the input voice signal is digitized by the A / D converter 111, and the CPU 1 operates in accordance with the program stored in the ROM 115 as in the conventional speech speed conversion device.
13 executes the speech speed conversion process. The digital voice signal after the voice speed conversion is converted into an analog signal by the D / A converter 114 inside the processor 110, and is output through the low pass filter 105 and the analog amplifier 104. The output sound is given to the headphones 300 or the speaker 400. RAM120
Are assigned to various buffers necessary for the speech speed conversion processing. The control circuit 130 changes the pressed state of the slow button 160 to
It is transmitted to the microprocessor 110 through the O circuit 112.
The control signal generation circuit 140 generates remote control information for controlling the operation of the recording / reproducing device 200 according to an instruction from the microprocessor 110. Remote control signal generator 15
0 outputs an infrared signal corresponding to the remote control information generated by the control signal generation circuit 140 to the recording / reproducing device 200.

FIG. 2 schematically shows the operation of the speech speed conversion apparatus executed inside the microprocessor. In this embodiment, a monitoring means 70 is prepared in addition to each means necessary for the operation of the conventional speech speed conversion apparatus shown in FIG.
The monitoring means 70 monitors the state of the output ring buffer 50 and gives a command to the control signal generation circuit 140 and the A / D conversion means 10 according to the amount of audio data stored in the output ring buffer 50. As described with reference to FIG. 1, the control signal generation circuit includes the remote control signal generation means in response to a command from the monitoring means.
A remote control signal such as infrared rays is generated through 150. The remote control signal generating means 150 generates a pause signal for temporarily stopping the reproduction operation of the recording / reproducing device connected to the speech speed conversion device and a pause release signal for restarting the reproduction. Also, the A / D conversion means 10 suspends or restarts the A / D conversion operation in response to an instruction from the monitoring means.

FIG. 3 shows the operation timing of each means controlled by the monitoring means 70. First, when the reproduction of the recording / reproducing device is started, the speech speed conversion device continues the speech speed conversion process of the input voice, and slowly outputs the converted voice.
Then, the output ring buffer accumulates audio data in an amount corresponding to the time delay between input and output. Next, when the time delay amount reaches the maximum value that can be held in the output ring buffer,
The operation of the A / D conversion means 10 is stopped by the monitoring means 70, a pause signal is generated through the control signal generation circuit 140, and the recording / reproducing apparatus stops reproduction of voice. Since the input voice is stopped and the A / D conversion operation is also stopped, there is no data input to the input buffer. Since there is no data to be processed, the speech speed conversion process 40 also suspends its operation. However, the output from the output ring buffer operates so that it is continuously output. As a result, the output ring buffer has no new input and the accumulated data continues to be output, so that the amount of accumulated audio data decreases. Then, when the accumulated voice data is exhausted, the monitoring means again gives a command to the control signal generation circuit and the A / D conversion means, generates a remote control signal for canceling the pause of the recording / reproducing apparatus, and restarts the A / D conversion operation. To work. By repeating this series of operations, it becomes possible for the voice reproduced by the recording / reproducing apparatus to exceed the limit due to the size of the output ring buffer and continue to convert the speech speed for a long time.

In the above description, for convenience of explanation, it is described that the state change occurs when the accumulated voice data amount reaches the maximum value that can be held in the output ring buffer and when the output ring buffer becomes empty. did. However, in reality, the recording / reproducing apparatus does not instantly respond to the remote control signal, and it may take time to pause or resume the reproduction. If there is a time delay when resuming playback, the speech speed converter will
Despite restarting D conversion and speech speed conversion processing, there is no audio input from the recording / playback device, and as a result,
The voice after the speed conversion is discontinuous. In order to avoid such a problem, it is desirable to give a margin to the timing when the above state change occurs. That is, although the amount of accumulated audio data is not the maximum value that can be held in the output ring buffer, the above-mentioned amount of audio data accumulated in the output ring buffer should be output sufficiently before it is sufficiently output. It is desirable to operate the monitoring means to cause a state change.

FIG. 4 shows a second embodiment of the present invention.
In this embodiment, the input buffer 30 is a ring buffer and the output buffer 50 is composed of two frame buffers. The input audio signal is A / D converted and then immediately recorded in the input ring buffer 30. During the through operation in which the speech speed conversion process is not applied, the audio data once recorded in the input buffer 30 remains as it is.
It is given to the D / A conversion means 60. Further, at the time of voice speed conversion, it is sent to the voice speed conversion processing 40 in frame units. Speech speed conversion processing
The audio data of the frame length subjected to 40 is recorded in one output buffer, while the audio data for which the speech speed conversion process has already been completed is recorded in the other output buffer.
It is output through the D / A conversion means 60. By inputting voice into the input ring buffer 30 and pipeline processing using two output buffers, a real-time voice speed conversion operation can be realized as in the first embodiment. Further, in the present embodiment, behind the input ring buffer, there is provided a reproduction address control means 80 for controlling the data output address from the input ring buffer and a repeat button 161 connected to it. The reproduction address control means 80 controls the read position of the data transferred from the input ring buffer 30. That is, when the voice is output through without the voice speed conversion process being performed, the reproduction address control means 80 controls the read address so that the data input immediately before is immediately output. However, the write address operates so as to advance one by one. As a result, the past voice of a fixed time corresponding to one round of the ring buffer is always held in the memory. Also, when the slow button 160 is pressed to enter the state of performing the voice speed conversion process, the reproduction address control means 80 operates so as to move the output address in frame units. In addition, the repeat button
When 161 is pressed, the output address is moved back in the past by a certain number of frames. This allows
In the present embodiment, in addition to the voice speed conversion operation, a repeat operation of repeatedly reproducing past voice can be realized. Further, when the slow button 160 is pressed during the repeat operation, it becomes possible to listen to the repeat reproduction sound slowly. This function is effective for language learning. Also, in this embodiment, as in the first embodiment, a monitoring means 70 is provided, which monitors the amount of voice data accumulated in the input ring buffer 30, and A / D conversion means according to the amount. Performs operations to control 10 and external recording / playback devices. This operation is the same as that of the first embodiment, and operates at the timing shown in FIG. Note that these operations are realized by a program on the microprocessor as in the first embodiment.

FIG. 5 shows the above-mentioned repeat reproduction.
It is a figure which showed the operation timing of each means which the said monitoring means controls. In this embodiment, the playback operation of the connected recording / playback apparatus is suspended during repeat playback. This is because if the repeat is repeated without stopping the input, the input ring buffer will eventually become full and the speech speed conversion operation thereafter cannot continue. First, when the repeat button is pressed while listening to the sound through, the repeat reproduction is started from the address traced back in the past in the input ring buffer. At this time, the monitoring means 70 stops the operation of the A / D conversion means 10 and stops the input to the input ring buffer 30, and at the same time, emits the pause signal of the remote controller through the control signal generation means 140, and the connected recording / reproducing device. Stop the playback operation of. Next, when the repeat reproduction is completed, a pause release signal of the remote controller is generated, and the reproduction of the recording / reproducing apparatus is restarted. With this series of operations, new audio data is not input to the input ring buffer during the repeat period, so that the input ring buffer will not overflow even if a large number of repeat operations are repeated.

Now, in the speech speed conversion apparatus of the present invention,
As shown in FIG. 1, it is a standard usage method that the user directly listens to the output through headphones or a speaker. However, there is also a method in which the voice slowly converted by the voice speed conversion device of the present invention is duplicated and recorded on another recording medium, and is used later.

FIG. 6 shows an example of connection between devices in such a usage method. This usage example uses a playback device with a left and right two-channel stereo playback audio output function,
This is a method in which the same voice is output to both channels, and then the voice speed of only the voice of one channel is converted and recorded on another medium. According to this method, the voice of one channel is recorded at the normal speed and the voice of the slow conversion is recorded in the other channel. The user of the duplicate recording can listen to the same voice at two different speeds by switching between the left and right voice channels according to the purpose.

FIG. 7 shows an example in which the same method is applied to video dubbing. In this case, a time delay occurs between the video and the voice whose voice speed is converted. However, in the speech speed conversion device of the present invention, the playback device side is occasionally paused at the timing shown in FIG. 2 to eliminate this time delay. That is, in the video created by this method, the normal speed sound synchronized with the image is recorded in one channel, and the slowly converted sound is recorded in the other audio channel. And the normal speed audio and images sometimes stop,
The slow sound of the other channel is recorded continuously. The stop state of the image and the normal speed voice operates so that the slowly converted voice is released when the voice catches up with the image.

In the above embodiment, the wireless control by the remote control signal such as infrared rays is used. However, a control line is provided between the voice speed conversion device and the recording / reproducing device, and these are directly connected. However, the same effect can be obtained even if the same control is performed.

[0031]

According to the present invention, it becomes possible to listen to recorded voice continuously for a long time while making the speech speed conversion process function. Further, it becomes possible to use the repeat operation or the voice speed conversion processing together with the repeat operation, and it becomes possible to avoid running out of the buffer memory for holding the input voice during the repeat operation.

[0032]

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram of operation timing in the embodiment of the invention.

FIG. 4 is an operation explanatory diagram of the second embodiment of the present invention.

FIG. 5 is an explanatory diagram of operation timing in the second embodiment of the present invention.

FIG. 6 is a diagram of an example of use of the present invention.

FIG. 7 is a diagram of an example of use using the video of the present invention.

FIG. 8 is an operation explanatory diagram of a conventional speech speed conversion device.

FIG. 9 is a configuration diagram of a conventional speech speed conversion device.

[Explanation of symbols]

10 ... A / D conversion means, 20 ... switch means, 30 ... input buffer, 40 ... speech speed conversion processing means, 50 ... output buffer, 60 ... D /
A conversion means, 70 ... Monitoring means, 80 ... Address control means, 100
… Speech rate converter, 101… Microphone, 102,104… Analog amplifier, 103,105… Low pass filter, 110… Microprocessor, 111… A / D converter, 112… I / O circuit, 113… CP
U, 114 ... D / A converter, 115 ... ROM, 120 ... External RAM, 130 ... Control circuit, 140 ... Control signal generating circuit, 150 ... Remote control signal generating means, 160 ... Slow button, 161, ... Repeat button, 20
0,201 ... Recording / reproducing device, 300 ... Headphones, 400 ... Speakers, 500,501 ... VCR

Claims (10)

[Claims] 1. An input voice is captured from a recording / playback device,
A speech speed converting device for outputting a voice whose voice speed is converted by expanding the time axis without changing the pitch of the input voice, and having a means for generating a control signal for controlling a reproduction operation of the recording / reproducing device. A speech speed conversion device characterized by the above. 2. A control signal for controlling a reproduction operation of the recording / reproducing apparatus is output in accordance with an amount of voice data accumulated in a memory means inside the speech rate converting apparatus in association with the speech rate converting process. The speech speed conversion device according to claim 1, wherein 3. The speech speed conversion apparatus, wherein the speech speed conversion apparatus expands and contracts the time length of an audio signal in frame units without changing the pitch, with A / D conversion means, an input buffer composed of a plurality of frame buffers, and a frame unit. A processing means, an output buffer having a ring buffer configuration in which addresses are circularly used, and a D / A conversion means, and a monitoring means for monitoring the amount of audio data accumulated in the output ring buffer; A control signal generating means for generating a control signal for controlling the reproducing operation of the reproducing means, wherein the monitoring means corresponds to the audio data amount accumulated in the output buffer,
3. The speech speed conversion apparatus according to claim 1, wherein the operation of the D conversion means and the operation of the control signal generation means are controlled. 4. The speech speed converting apparatus comprises an A / D converting means, an input buffer having a ring buffer structure in which addresses are circularly used, a reproduction address control means for controlling a read address from the input buffer, and a frame. A voice speed conversion processing unit that expands and contracts the time length of a unit audio signal without changing the pitch, an output buffer composed of a plurality of frame buffers, and a D / A conversion unit, and the input ring buffer It has a monitoring means for monitoring the amount of audio data to be stored and a control signal generating means for generating a control signal for controlling the reproduction operation of the recording / reproducing apparatus, and the monitoring means is stored in the input buffer. 3. The operation of the A / D conversion means and the operation of the control signal generation means are controlled according to the amount of audio data to be reproduced. Of the speech speed conversion apparatus. 5. In the control by the monitoring means, the amount of voice data accumulated in the input or output ring buffer is
When the maximum amount that can be held in the input or output ring buffer is approached, the playback of the recording / playback device and the A / D
When the operation of the conversion means is temporarily stopped, the voice speed conversion processing is continued, the accumulated voice data is output, and the accumulated voice data amount in the input or output buffer approaches 0,
5. The speech speed converting apparatus according to claim 3, wherein the speech speed converting apparatus operates so that the reproducing operation of the recording / reproducing apparatus and the operation of the A / D converting means are started again. 6. The speech speed conversion device has a repeat function for repeatedly reproducing past voices, and when the repeat function is executed, the monitoring means causes the recording / reproducing device and the A / D conversion means. 5. The speech speed conversion device according to claim 4, wherein the operation is stopped so that new input voice data does not enter the input ring buffer during the repeat operation. 7. The speech speed converting apparatus according to claim 1, wherein the control signal for controlling the operation of the recording / reproducing apparatus is a wireless remote control signal. 8. The speech speed conversion device comprises a low-pass filter for the purpose of anti-aliasing in input and output of an analog audio signal, an A / D converter, and a D / A converter.
A microprocessor, an external memory, a control button, and a control circuit for inputting the state of the control button to the microprocessor, and means for generating a control signal for controlling the recording / reproducing apparatus. Have and
The speech speed conversion apparatus according to any one of claims 1 to 7, wherein the series of operations is realized by a software program on the microprocessor. 9. A recording / reproducing apparatus having two input channels, wherein audio is reproduced by a recording / reproducing apparatus having two output channels, and the same audio signal is outputted from both of the two output channels. , In a system for duplicating and recording voice, a voice speed conversion device for executing a voice speed conversion process for expanding and contracting the time length of the voice signal is provided between the signal paths of one channel, and the one channel A method of using the speech speed conversion device, which is characterized in that only the voice of the above is converted into a speech speed and recorded, and the voice of the normal speed is recorded on the other channel. 10. The speech speed conversion device is the speech speed conversion device according to any one of claims 1 to 8.
A method of using the speech speed conversion device according to claim 9.