JPS6193712A - Sound quality adjusting device in audio equipment - Google Patents

Abstract

PURPOSE:To attain automatic sound quality adjustment suitable for music and conversation by switching a sound quality adjusting circuit depending on the presence of periodicity of an audio signal waveform. CONSTITUTION:A rhythm discriminating circuit 2 discriminates the presence or absence of the periodicity of a signal waveform of an audio signal from a signal source 1. When the presence of periodicity is discriminated, a discrimination signal is outputted to throw a changeover switch 3 to the position of a contact 2. Thus, the audio signal from the signal source 1 is fed to a sound quality adjusting circuit 5 which adjust the sound quality to obtain a frequency characteristic suitable for a music. On the other hand, when no periodicity exists, since no discrimination signal is outputted, the switch 3 is thrown to the position of contact 1. Thus, the audio signal is fed to a sound quality adjusting circuit 4 which adjusts the sound quality to obtain a frequency characteristic suitable for a conversation. Then the sound quality adjustment suitable for music/conversation is attained automatically.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a sound quality system in which the output frequency characteristics of an audio device can be automatically adjusted according to an audio signal corresponding to music, conversation, etc. from a signal source. Relating to an adjustment device.

[Prior Art] Conventionally, common audio devices have a bass adjustment that adjusts the output frequency characteristics of the bass range, a treble adjustment that adjusts the output frequency characteristics of the treble range, and a bass adjustment that adjusts the output frequency characteristics of the treble range.
Sound quality adjustment devices such as %□, □engine, □65, and Eyu adjustment are provided (see page 112 of the New Automobile Engineering Handbook, Part 7, published on May 31, 1988). The user of the audio device then adjusts the audio signal output from the speaker, such as a tape deck, radio, etc., so that the sound quality matches his or her preference or is easy to listen to. The user operates the operation knobs, operation switches, etc. of each sound quality adjustment device. Specifically, when listening to music, for example, you can adjust the bass and treble using each control knob to emphasize the low and roaring range, and further enhance the low and high range by turning on the loudness adjustment switch. I'm emphasizing it. On the other hand, when listening to conversations such as radio news broadcasts, if the bass and treble frequencies are emphasized as described above, the bass becomes particularly muffled and difficult to listen to, so the bass adjustment, treble adjustment, and loudness adjustment described above It is designed to attenuate the low and high frequencies.

[Problems to be Solved by the Invention] By the way, as mentioned above, audio devices emphasize low and high frequencies when listening to music, and emphasize low and high frequencies when listening to conversations, etc.
Generally, the appropriate sound quality, such as attenuation of high-frequency ranges, differs depending on when listening to music and when listening to conversation.

However, with conventional audio equipment, when listening to music and conversation alternately, such as when listening to radio broadcasts, in order to obtain the appropriate sound quality for each, it is necessary to operate the operation knobs and operation switches of each sound quality adjustment device each time. Must.

Especially when it comes to in-vehicle audio equipment, it is extremely troublesome to perform such sound quality adjustment operations while driving.
In reality, the current situation is that once the sound has been adjusted to suit the purpose of the passenger (music-based, conversation-based), radio broadcasts are listened to at that sound quality.

[Means for Solving the Problems] The present invention has been made in view of the above problems, and provides an audio device that can automatically produce sound quality W4M suitable for music and conversation, or more suited to one's taste. In order to achieve this objective, the first invention of the present application focuses on the fact that music and conversation can be distinguished depending on the presence or absence of so-called rhythm (periodicity of audio signal waveforms). , a rhythm determining means for determining whether or not the signal waveform of the audio signal output from the signal source has periodicity, and when the rhythm determining means determines that there is periodicity, the output frequency characteristic has a low to high range. Further, the second invention of the present application further provides the Pf! of music by adjusting the strength of the so-called beat (difference in strength of the audio signal). Rhythm discriminating means for discriminating whether or not the signal waveform of an audio signal output from a signal source has periodicity, focusing on the ability to discriminate between types of music, such as rock, jazz, and talassic music, and this rhythm discriminator. beat discrimination means for discriminating that the strength difference of the audio signal determined to have periodicity by the means is a predetermined 11fi or more; a first sound quality adjustment means for attenuating the high frequency range; and a first sound quality adjustment means for making the output frequency characteristics uniform when the rhythm determining means determines that there is periodicity and the beat determining means determines that there is no difference in intensity. and a third sound quality that emphasizes the low and high range of the output frequency characteristic when it is determined that there is periodicity by the rhythm determining means and that there is a difference in intensity by the beat determining means. It is configured to have an adjustment means.

[Embodiments of the invention] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an example of a sound quality adjustment device according to the first invention. In the figure, 1 is a signal source such as a radio or tape deck that generates an audio signal, and 2 is a device that determines whether or not the signal waveform of the audio signal output from signal source 1 has periodicity. It is a rhythm discrimination circuit that outputs a discrimination signal when there is a rhythm.
The specific configuration of this rhythm discrimination circuit is as shown in FIG. 2, for example, as will be described later. 3 is a normal contact (1
) and is switched to contact (2) by the discrimination signal from the rhythm discrimination circuit 2, 4 is a sound quality adjustment circuit that adjusts the sound quality so that the frequency characteristics are suitable for conversation, etc., and 5 is a sound quality adjustment circuit for music. This is a sound quality adjustment circuit that adjusts the sound quality to obtain suitable frequency characteristics.The audio signal from the signal source 1 is sent to the sound quality adjustment circuit 4 via the contact (1) of the changeover switch 3, and the audio signal is sent to the changeover switch 3. The signals are inputted to the sound quality adjustment circuit 5 through the contacts (2). Further, 6 is an amplifier that amplifies the audio signal that has passed through the sound quality adjustment circuit 4 or 5, and the audio signal that has undergone sound quality adjustment is transmitted to a speaker (not shown) through this amplifier 6. It has become.

The output frequency characteristics of each sound quality adjustment circuit 4.5 are as follows:
It may be fixed in advance, or may be changed according to the preference of the user of the audio device.

To explain the specific configuration of the above-mentioned rhythm discrimination circuit 2, in FIG. This is a differential circuit that performs differential processing on the signal of 22.
The output stage of is clamped, for example by a diode, so that there is no response to negative changes in the input signal.

23 is a pulse generation circuit that outputs a pulse signal of a predetermined period, and 24 is a counter that clears the current count value every time a trigger signal from the differentiating circuit 22 is input and counts the pulse signal from the pulse generation circuit 23. , 25 is the differential circuit 2
This is a sample hold circuit that stores and holds the count value in the counter 24 in synchronization with the trigger signal from the counter 24. and,
26 is an arithmetic circuit, and this arithmetic circuit 26 compares each count value sampled by the sample hold circuit 25 within a predetermined time to detect the minimum value, and each count value is determined to be the minimum value. ≠11 signal is output when the value is approximately an integer multiple of . That is, this performance bond circuit 2
The discrimination signal from 6 becomes the discrimination signal of the rhythm discrimination circuit 2.

Next, the operation will be explained according to the timing chart shown in FIG.

When listening to a music broadcast program from a signal source 1, for example, a radio, when an audio signal corresponding to the music is input to the rhythm discrimination circuit 2, the low frequency component signal in the audio signal that has passed through the low-pass filter 21 is differentiated. Differential processing is performed by the circuit 22. At this time, since the rhythm is generally carved by a bass instrument in music, the signal passing through the low-pass filter 21 has a waveform that is synchronized with the rhythm of the music, and the output signal from the differentiating circuit 22 is also synchronized with the rhythm. Become. Here, for example, as shown in FIG. 3, times t1, t2, t3, t4, . . .
When the trigger signal is output from the differentiating circuit 22,
The counter 24 clears the previous count value each time the trigger signal is input, and counts the pulse signal from the pulse generator circuit 23, and the count values C1, C2, C3, . . .
... is sampled and held by the circuit 25, and the count value C sampled as above within a predetermined time
The arithmetic circuit 26 detects the minimum value from 1, C2, C3, . . . and determines whether each count value is approximately an integer multiple of the minimum value. At this time, since the output of the trigger signal from the differentiating circuit 2.2 is synchronized with the rhythm of the music, the arithmetic circuit 26 performs the discrimination output, that is, the discrimination signal is output from the rhythm discrimination circuit 2. . When the discrimination signal is output from the rhythm discrimination circuit 2 in this way,
This discrimination signal causes the selector switch 3 to switch to the contact (2) side, and the audio signal from the signal source 1 is changed by the sound quality adjustment circuit 5 to have its output frequency characteristics, for example, a characteristic that emphasizes the low and high frequencies (predetermined). characteristics). After the sound quality has been adjusted in this way, the amplifier 6
The audio signal is output from the speaker as reproduced sound via the .

On the other hand, when listening to a news broadcast after a music program broadcast as described above, an audio signal corresponding to a conversation from the signal source 1 (radio) is input to the rhythm discrimination circuit 2. At this time, since various conversations do not have a regular rhythm, the audio signals corresponding to these conversations have no periodicity. Therefore, as mentioned above, each count value sampled by the sample-hold circuit 25 in the rhythm discrimination circuit 2 has no relationship such that each count value is approximately an integer multiple of the minimum value, and the arithmetic circuit 26 outputs a discrimination output. is not done. Therefore, no discrimination signal is output from the rhythm discrimination circuit 2, and the changeover switch 3 is not switched to the contact (1) side. When the selector switch 3 is switched to the contact (1) side in this way, the audio signal from the signal source 1 is changed by the sound quality adjustment circuit 4 to have its output frequency characteristics changed to, for example, a characteristic in which the low and high frequencies are attenuated (conversation is preliminarily suppressed). After that, the audio signal is adjusted to a characteristic determined to be easy to hear, and then the audio signal is outputted from the speaker as reproduced sound via the amplifier 6.

FIG. 4 is a block diagram showing another example of the sound quality adjustment device according to the first invention. This embodiment uses a loudness circuit as a sound quality adjustment means. In Figure 4,
A signal source 1 that outputs an audio signal, a rhythm discrimination circuit 2 that determines whether the audio signal waveform from the signal source 1 has periodicity, and an amplifier 6 that amplifies the audio signal from the signal source 1 are shown in FIG. This embodiment is substantially similar to the embodiment shown in FIG.

7 is a switching contact that is normally on the contact (1) side and switches to contact (2) in response to the discrimination signal from the rhythm discrimination circuit 2;
Discriminator 8 is a loudness circuit that emphasizes predetermined low and high frequency bands of the audio signal, and 9 is an output detection circuit that detects the signal level of the audio signal via amplifier 6 and outputs a detection signal when the level is below a predetermined level. , the contact (1) of the changeover switch 7 is directly connected to the amplifier 6, and the contact (2) of the changeover switch 7 is connected to the amplifier 6 via the loudness circuit 8.

Then, when the output detection circuit 9 outputs the detection signal, the operation of the rhythm discrimination circuit 2 becomes effective.

In such a sound quality adjustment device, when the output level of the audio signal exceeds a predetermined level, the rhythm discrimination circuit 2 does not operate, and the changeover switch 7 always holds contact (1).
The audio signal from the signal source 1 is directly output as reproduced sound from the speaker via the amplifier (note that sound quality adjustment by normal manual operation is possible using a separate system).

On the other hand, when the output level of the audio signal falls below a predetermined level, the rhythm determination circuit 2 is activated, and if the audio number 413 from the signal source 1 corresponds to music, the rhythm is determined according to the rhythm as in the above embodiment. The changeover switch 7 is switched to the contact (2) side by the discrimination signal from the discrimination circuit 2, and the audio signal from the signal source 1 has its low and high frequencies emphasized by the loudness circuit 8. Further, in a situation where the output level of the audio signal is below a predetermined level, if the audio signal from the signal source 1 corresponds to a conversation, the rhythm discrimination circuit 2 outputs the discrimination signal as in the above embodiment. First, the changeover switch 7 is switched to contact (1), and the audio signal from the signal source 1 is passed through the amplifier 6 to fFL and outputted as reproduced sound from the speaker as in the normal case.

In each of the above embodiments, the specific configuration of the rhythm discrimination circuit 2 is as shown in FIG. 2, but the specific configuration of the rhythm discrimination circuit 2 may be as shown in FIG. 5, for example. good. This is configured such that a pulse count is performed every other trigger signal obtained by differentiating an audio signal passed through a low-pass filter 21 in a differentiating circuit 22. That is, a changeover switch 27 is provided that switches contacts (1) and (2) in synchronization with the trigger signal from the differentiating circuit 22, and the changeover switch 27 switches between contacts (1) and (2).
) people, through! pulse generation circuit 23
The counter 24 is configured to count the pulse signals from.

Then, the sample and hold circuit 25 sequentially samples the counted value of the counter 24, and the arithmetic circuit 26 detects the minimum value of each counted value sampled within a predetermined time, and each counted value is approximately an integer multiple of the minimum value. I am trying to determine whether it is or not.

In such a rhythm discrimination circuit 2, for example, as shown in FIG.
When a trigger signal is output from the differentiating circuit 22, the changeover switch 27 performs a switching operation of contacts (1) and (2) in synchronization with the signal at each time. the result,
Time t1 and t2 when the changeover switch 27 is on the contact (1) side
Between time (3 and t4...), the counter 24 counts the pulse signals from the pulse generation circuit 23, and the counted values C1, C2,... It is sampled by the hold circuit 25. Then, the arithmetic circuit 26 performs the discrimination operation based on the sampled value.

In addition, in the embodiment according to the first invention, it is assumed that the sound quality is adjusted such that the low and high ranges are attenuated for conversations without rhythm, and the low and high ranges are emphasized for rhythmic music. However, the characteristics of the sound quality adjustment are not limited to these, and can be arbitrarily set according to the preferences of the user of the audio device. Furthermore, it is also possible to configure the tone quality adjustment circuit to automatically adjust the output frequency characteristics according to the state of the discrimination signal from the rhythm discrimination circuit 2.

FIG. 7 is a block diagram showing an example of the sound quality adjustment device according to the invention of the present invention.

In the figure, a signal source 1 and a rhythm discrimination circuit 2 are the same as those shown in the embodiment according to the first invention. 10 is a beat discrimination circuit which outputs a discrimination signal when the difference in strength of the audio signal from the signal source 1 exceeds a predetermined value; this beat discrimination circuit 10 is activated by a discrimination signal from the rhythm discrimination means 2; When the audio signal from the signal source 1 is jazz or rock music with a so-called beat, a discrimination signal is output based on the difference in strength of the audio signal.

In addition, 11 is normally on the contact (2) side, and the rhythm discrimination circuit 2
The changeover switch 12 normally switches to the contact (2) side according to the discrimination signal output from the beat discrimination circuit 10, and switches to the contact (1) side according to the discrimination signal output from the beat discrimination circuit 10.
) side, and 13 is a selector switch that changes to the frequency characteristic 11 suitable for jazz and rock music, for example, low and
14 is a sound quality adjustment circuit that adjusts the sound quality to have a frequency response that emphasizes the treble range; 14 is a sound quality adjustment circuit that adjusts the sound quality to have a frequency response that is suitable for classical music, for example, a flat frequency response; 15 is a conversation This is a sound quality adjustment circuit that adjusts sound quality to attenuate frequency characteristics suitable for, for example, low and high frequency ranges. Then, the contact (1) of the changeover switch 11 is connected to the input end of the changeover switch 12, and the contact (2) of the changeover switch 11 is connected to the input terminal of the changeover switch 12.
The contact (1) of the adjustment switch 15 and the changeover switch 12 is connected to the sound quality adjustment circuit 13, and the contact (2) is connected to the sound quality adjustment circuit 14, respectively, and the sound quality is adjusted by each Oga adjustment circuit 13, 14, and 15. The audio signal is further passed through amplifier 6.

- adapted to be transmitted to a force (not shown);

Note that the output frequency characteristics of each sound quality adjustment circuit 13, 14, and 15 may be fixedly determined in advance, or may be changed according to the preference of the user of the audio device.

In the above-mentioned sound quality adjustment device, when the audio signal from the signal source 1 corresponds to a conversation or the like, the first
Similarly to the embodiment of the invention, the rhythm discrimination circuit 2 does not output the discrimination signal, and the changeover switch 11 maintains the contact (2) state. As a result, the output frequency characteristics of the audio signal from the signal source 1 are adjusted by the sound quality adjustment circuit 15 as the first sound quality adjustment means, for example, so that the low and high frequency ranges are attenuated)41. A, 76, Yu, -
Kaya. , Eng. −8, Manufactured output is produced.

On the other hand, when the audio signal from the signal source 1 corresponds to music without a so-called beat, such as classical music, the rhythm of the music causes the same rhythm as in the embodiment of the first invention. A discrimination signal is output from the discrimination circuit 2. Then, the beat discrimination circuit 10 is activated by the discrimination signal from the rhythm discrimination circuit 2, but the difference in strength of the audio signal corresponding to the music without the so-called beat does not exceed a predetermined value as in the above. , this beat discrimination circuit 10 does not output the discrimination signal. As a result, the changeover switch 11 switches to contact (1), but the changeover switch 12 maintains contact (2), so the audio signal from the signal source 1 is passed through the sound quality adjustment circuit 14 as the second sound quality adjustment means. The output frequency characteristics are adjusted, for example, so that the frequency characteristics are flat, and the output is outputted as reproduced sound via the amplifier 6 and the speaker.

In addition, if the audio signal from the signal source 1 corresponds to music with a so-called beat, such as jazz or rock music, the rhythm discrimination circuit 2 determines the rhythm due to the rhythm of the music in the same way as above. A signal is output. Then, the beat discrimination circuit 10 activated by the discrimination signal from the rhythm discrimination circuit 2 detects the discrimination signal because the difference in strength of the audio signal corresponding to the so-called beat-based music exceeds a predetermined value as described above. Output. As a result, both of the changeover switches 11 and 12 are switched to contact (1), so that the output frequency characteristics of the audio signal from the signal source 1 are adjusted by the sound quality adjustment circuit 13 as the third sound quality adjustment means. After being adjusted to emphasize the low and treble ranges, the sound is output as reproduced sound via the amplifier 6 and the speaker.

As described above, according to this embodiment, when the audio signal from the signal source 1 corresponds to a conversation, etc., the sound quality is automatically adjusted so that the conversation is more effective, and the audio signal from the signal source 1 is automatically adjusted to make the conversation more effective. If the audio signal from the device corresponds to music, the sound quality can be automatically adjusted to suit the type of music, whether it is music with a beat or not.

FIG. 8 is a block diagram showing another example of the sound quality adjustment device according to the second invention. This embodiment uses a loudness circuit as a sound quality adjustment means. Signal source 1, rhythm discrimination circuit 2. Beat discrimination circuit 10 and each changeover switch 1
1.12 is similar to that shown in FIG. Here, the contact (1) of the changeover switch 12 is connected to the amplifier 6 via the loudness circuit 8, and the contacts (2) of both the changeover switches 11 and 12 are directly connected to the amplifier 6.

In such a sound quality adjustment device C, when the audio signal from the signal source 1 corresponds to a conversation without rhythm, the changeover switch 11 holds the contact (2), so that the audio signal is The sound is output directly from the speaker as a reproduced sound via the same contact point (2) and the amplifier 6 (the sound quality: 14 adjustment by normal manual operation can be achieved by a separate system). In addition, when the audio signal from the signal source 1 corresponds to music without a beat, such as Clara Schiff music, the discrimination by the rhythm discrimination means 2 is performed as in the embodiment shown in FIG. The signal causes the changeover switch 11 to switch to contact (1) and the changeover switch 12 to maintain contact (2), so the audio signal is transferred to contact (1) of changeover switch 11 and contact (2) of changeover switch 12. ) and are output as reproduced sound from the speaker via the amplifier 6 (also in this case, the sound quality can be adjusted by normal manual operation using a separate system).

Furthermore, if the audio signal from the signal source 1 corresponds to music with a so-called beat, such as jazz or rock music, a discrimination signal is output from both the rhythm discrimination circuit 2 and the beat discrimination circuit 10, and the switching is performed. Since both switches 11 and 12 are switched to contact (1), the output from signal WA1 is OFF! - Switch 11 to change the audio signal.
input to the loudness circuit 8 through 12 contacts (1),
After the low and treble ranges are emphasized, the sound is output from the speaker via the amplifier 6 as a reproduced sound.

In the embodiment described above, only the so-called beat-based music such as jazz and rock music has its low and roaring ranges emphasized by the loudness circuit 8.

In addition, in each of the embodiments according to the second invention, the low and high ranges are attenuated for conversations without rhythm, and the frequency characteristics are flat for music that does not have a so-called beat, such as Clara Schiff music. As mentioned above, for music with a strong beat, such as jazz and rock music, we assumed that the sound quality would be adjusted to emphasize the low and high ranges.
The characteristics of the sound quality adjustment are not limited to these, but can be arbitrarily set according to the preferences of the user of the audio device.

Further, it is also possible to configure the tone quality adjustment circuit to automatically adjust the output frequency characteristics according to the states of the discrimination signals from the rhythm discrimination circuit 2 and the beat discrimination circuit 10.

[Effects of the Invention] As explained above, according to the invention of Application 1, in an audio device, the sound quality is automatically adjusted to make it easier to listen to music and conversation, or to suit the user's preference. In addition, according to the invention of Application No. 2,
Furthermore, automatic sound quality adjustment for music becomes possible depending on the type of music, that is, music with a strong beat and music without a beat. As a result, even when listening to music and conversation alternately, such as in a radio broadcast, the sound quality is m1! This eliminates the need to perform the above steps, making the sound quality adjustment device particularly suitable for in-vehicle audio devices.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a sound quality adjustment device according to the invention of the present invention, FIG. 2 is a block diagram showing an example of a specific configuration of the rhythm discrimination circuit in FIG. 1, and FIG. FIG. 4 is a block diagram showing another example of the sound quality adjustment device according to the invention of Item 1 of the present application, and FIG. 5 is another example of the specific configuration of the rhythm determining circuit. FIG. 6 is a timing chart showing the operation of the rhythm discrimination circuit shown in FIG. FIG. 2 is a block diagram showing another example of the sound quality adjustment device according to the second invention. 1... Signal source 2... Rhythm discrimination circuit 3.7.11, 12.27... Changeover switch 4.5.
13, 14.15... Sound quality adjustment circuit 6... Amplifier 8... Loudness circuit 9... Output detection circuit 10... Beat discrimination circuit 21... O-bass filter 22... Differentiating circuit 23...Pulse generation circuit 24...Counter 25...Sample bold circuit 26...Arithmetic circuit

Claims (1)

[Claims] 1) Rhythm determining means for determining whether the signal waveform of an audio signal output from a signal source has periodicity;
A sound quality adjustment device for an audio device, comprising a sound quality adjustment device that adjusts the output frequency characteristic so as to emphasize low and high frequency ranges when the rhythm determination device determines that there is periodicity. 2) The rhythm determining means includes a low-pass filter that passes an audio signal having a predetermined frequency or less, a signal generating means that outputs a trigger signal in synchronization with the signal passed through the low-pass filter, and a trigger signal from the signal generating means. 2. The sound quality adjustment device for an audio device according to claim 1, further comprising a determining means for determining whether or not there is periodicity based on the output period of the output signal. 3) rhythm determining means for determining whether the signal waveform of the audio signal output from the signal source has periodicity;
beat discrimination means for determining whether the strength difference of the audio signal determined to have periodicity by the rhythm determination means is greater than a predetermined value; and an output frequency when the rhythm determination means determines that there is no periodicity. A first sound quality adjusting means for attenuating the low and high frequency range of the characteristic; and when the rhythm determining means determines that there is periodicity, and the beat determining means determines that there is no difference in intensity, the output frequency characteristics are made uniform. and a second sound quality adjustment means for emphasizing the low and high tones of the output frequency characteristic when the rhythm discriminating means determines that there is periodicity and the beat discriminating means determines that there is a difference in intensity. 3. A sound quality adjustment device for an audio device, characterized in that it has a sound quality adjustment means. 4) The rhythm determining means includes a low-pass filter that passes an audio signal having a predetermined frequency or less, a signal generating means that outputs a trigger signal in synchronization with the signal passed through the low-pass filter, and a trigger signal from the signal generating means. 4. The sound quality adjustment device for an audio device according to claim 3, further comprising a determining means for determining whether or not there is periodicity based on the output period of the output signal.