JPH0897655A - Graphic equalizer - Google Patents

Abstract

PURPOSE: To prevent an audio signal from being distorted due to an excess input to a post-stage amplifier even when the graphic equalizer is wrongly used such that all components are adjusted to their maximum position. CONSTITUTION: An attenuator 19 is provided before a buffer amplifier 12 at a pre-stage of the graphic equalizer 11. A microcomputer 16 detects the adjustment state of each component of the graphic equalizer 11, sums level increases of each component to actuate an attenuator 19 or to increase the attenuation when the result indicates a prescribed level or over thereby attenuating an input signal and providing an output to the buffer amplifier 12. The attenuated level is corrected by controlling a volume controller 14 at a post-stage by a microcomputer 16, then no listening sense is changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graphic equalizer incorporated in an audio device.

[0002]

2. Description of the Related Art A so-called graphic equalizer, which divides an audible frequency band into a plurality of continuous bands and makes it possible to adjust the amplification degree of each divided band, is a frequency characteristic of an audio device or a listening room. It is incorporated and used in many devices to correct the. FIG. 5 illustrates a block configuration diagram of a circuit in the peripheral stage of a graphic equalizer in a general audio device.

In the figure, reference numeral 21 is a graphic equalizer. In this example, the audible frequency band is divided into nine bands, and gain adjustment of about ± 9 dB is possible for each band. 22 and 23 are buffer amplifiers before and after the graphic equalizer 21, 2
Reference numeral 4 is a volume control, and an electronic volume is used. Reference numeral 25 is an amplifier, and 26 is a microcomputer for controlling the volume control 24 and the graphic equalizer 21. Reference numeral 27 is an input key for operation, and 28 is a display for displaying necessary items.
It is connected to the.

As a method of using a general consumer graphic equalizer using such a circuit, in the case of no adjustment, each frequency point is 0d as shown in FIG.
Horizontally arranged at the B level, and the frequency characteristics are shown in FIG. 6 (B).
It is flat like. From this state, in order to correct the unevenness of the frequency characteristics at the listening point in the listening room as flat as possible, for example, each frequency point is adjusted as shown in FIG. The correct usage is to create such frequency characteristics.

However, most users have a psychological problem of human beings and fully increase all adjustable frequency points to adjust each frequency point as shown in FIG. Frequently, the frequency characteristic shown in FIG. 7B is used, and the usage of the original function is hardly performed.

[0006]

In the above-mentioned state, the frequency characteristic is not corrected, but in addition to that, in addition to the frequency characteristic flat state of FIG. 23 to 10 dB over each frequency band
This means that a signal having a large amplitude (depending on the Q characteristic and the octave division ratio) is input, in other words, the dynamic range of the signal system is reduced by 10 dB or more in the middle range, and distortion occurs at a high volume.

It may be considered to prepare a circuit corresponding to such a signal input with a large amplitude to deal with it, but since it is an unnecessary specification in a normal use state, the quality is excessive and the cost is increased. I can't avoid it
Even if such measures are taken, it is not possible for the user to realize the value.

As a technique for improving the above-mentioned inconvenience, Japanese Unexamined Patent Publication No. 1-186007 discloses that if the elements of the graphic equalizer are upgraded to a certain value or more,
It is described that the band of the entire graphic equalizer is lowered by a predetermined value. However, according to this technique, when the operation is performed such that one element is decreased to the maximum and all the other elements are increased to the maximum, or when only one band is minimized, the entire volume cannot be lowered, and thus the distortion is reduced. It could not prevent the occurrence. The present invention aims to solve the above-mentioned inconveniences, including the elimination of such inconveniences.

[0009]

According to the present invention, the above-mentioned problems include an element for dividing a reproduction frequency band into a plurality of continuous frequency bands and adjusting a gain of a predetermined amount for each frequency band. In the graphic equalizer, control means for detecting the adjustment amount of each element, and ON / OFF or an increase / decrease in attenuation amount under the control of the control means are provided, and an attenuator provided before or after the graphic equalizer. And a volume control for controlling the volume controlled by the control means,
The control means calculates the adjustment amount of each detected element, and solves the problem by controlling the attenuator and the volume control according to the calculation result.

Further, in the preceding paragraph, the calculation is to add the positive adjustment side of the detected adjustment amounts of the respective elements, and the control is to make the attenuator operate when the addition value exceeds a predetermined value. This can be solved by increasing the ON or attenuation amount by a predetermined amount and increasing the volume control by a predetermined volume.

Further, according to the present invention, the above-mentioned problem is solved in a graphic equalizer having an element for dividing a reproduction frequency band into a plurality of continuous frequency bands and adjusting a gain by a predetermined amount for each frequency band. , A control means for detecting an adjustment amount of each element, and a gain controlled by the control means to change the gain,
An amplifier provided before or after the equalizer, and a volume control for adjusting the volume controlled by the control means, the control means calculates the adjustment amount of each element detected, and the result of the calculation, This is solved by controlling the gain and volume control of the amplifier.

Further, in the preceding paragraph, the calculation is to add the positive adjustment side of the detected adjustment amount of each element, and the control is for the amplifier when the addition value exceeds a predetermined value. This can be solved by reducing the gain by a predetermined amount and increasing the volume control by a predetermined volume.

[0013]

[Function] The attenuator or variable gain amplifier provided in front of or immediately after the graphic equalizer is controlled by the control means for detecting the adjustment state of each element of the graphic equalizer adjusted by the user, and is adjusted to the adjustment state. Set to attenuation or gain. Therefore, in an erroneous use state in which all the elements are set to the highest position, the control means detects and calculates the adjustment state of each element, and the result exceeds the predetermined value. If so, turn it on or increase the attenuation. If the gain is a variable gain amplifier, its gain is reduced. Furthermore, in any case of an attenuator or a variable gain amplifier, the volume reduction is controlled by the gain reduction amount to raise the volume, so that the problem of distortion due to excessive input is cleared without causing a hearing problem. be able to.

[0014]

1 is a block diagram of a circuit of an embodiment of the present invention. In the figure, 11 is a graphic equalizer, and in this example, the audible frequency band is changed from f1 to f9.
It is divided into 9 bands up to, and each band is provided with an element capable of gain adjustment of about ± 9 dB. 1
2 and 13 are buffer amplifiers before and after the graphic equalizer 11, and 14 is a volume control, and an electronic volume is used. 15 is an amplifier, 16
Is a microcomputer as a control means for controlling the volume control 14 and the graphic equalizer 11. Reference numeral 17 is an input key for operation, and 18 is a display for displaying necessary items, both of which are connected to the microcomputer 16.

Reference numeral 19 denotes an attenuator that is inserted in series with the input side of the buffer amplifier 12 in the preceding stage of the graphic equalizer 11, and is controlled by the microcomputer 16 together with the graphic equalizer 11.

The circuit of the present invention having such a configuration operates as follows. That is, f1 adjusted by the user
The microcomputer 16 detects the level adjustment value of the element for each frequency adjustment band from f9 to f9, and calculates each value by a constant calculation formula, and the result is distortion due to excessive input to the buffer amplifier 13 in the subsequent stage. If so, the microcomputer 16 controls the attenuator 19 to turn it on,
Alternatively, it is adjusted so as to increase the attenuation value. The attenuator 19 is not particularly operated unless the amplifier has a large input that causes distortion.

For example, the simplest calculation formula is f1
It is possible to add the level adjustment values of the elements for each frequency adjustment band from f9 to f9 and turn on / off the attenuator 19 depending on whether the added value exceeds a certain value.
If the constant value is n, the level adjustment values of the elements for each frequency adjustment band from f1 to f9 are added, and if the result is larger than n, the attenuator 19 is turned on, and n
If it is equal to or smaller than n, the microcomputer 16 controls the attenuator 19 so that the attenuator 19 is turned off.

FIG. 2A shows the case where the graphic equalizer 11 is completely unadjusted, and the elements from f1 to f9 are arranged side by side at a level of 0 dB as shown in FIG. It is flat like (B). From this state, the user fully enhances all adjustable frequency points as shown in FIG. 3A, adjusts each element as shown in FIG. Even if the frequency characteristic exceeds +9 dB in most of the bands as in B), the microcomputer 16 adds the level adjustment value of each element for each frequency adjustment band from f1 to f9,
Since the result is larger than n, the attenuator 19 is turned on, and as shown in FIG. 4B, the audio signal is distorted by the buffer amplifier 13 because it is attenuated by 12 dB and input to the buffer amplifier 13. There is no.

Then, by controlling the microcomputer 16 so that the volume control 14 in the subsequent stage raises the volume portion attenuated by the attenuator 19, it is possible to eliminate a change in the volume of the sound.

For further practical use, the level adjustment value for each frequency adjustment band may be weighted in consideration of the frequency characteristics of the amplifier, the characteristics of the listening room, and the like.

In the above embodiment, the attenuator 19 is used.
Although it was configured to be provided separately from the graphic equalizer 11, a graphic control with a built-in level control that can also be used as an attenuator
If an equalizer IC is used or the gain of the buffer amplifier is adjusted, the cost can be increased with almost no increase.

[0022]

As described above, according to the present invention, the microcomputer detects the state of each element of the graphic equalizer adjusted by the user, and the numerical value of the adjustment amount is calculated by a constant calculation formula, Since the attenuator is controlled based on the result and ON / OFF or the amount of attenuation is adjusted, it is possible to prevent the sound quality from being deteriorated due to an incorrect usage by the user. The attenuator is low-priced and cost increase can be minimized. Further, even if a graphic equalizer IC with a built-in level control that can also be used as an attenuator is used or the gain of a buffer amplifier is adjusted, it can be implemented with almost no increase in cost. .

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a circuit according to an exemplary embodiment of the present invention.

FIG. 2A is an adjustment state diagram of an element according to an embodiment of the present invention. (B) Frequency characteristics resulting from adjustment of the device of one example of the present invention.

FIG. 3A is an adjustment state diagram of an element according to an example of the present invention. (B) Frequency characteristics resulting from adjustment of the device of one example of the present invention.

FIG. 4A is an adjustment state diagram of an element according to an example of the present invention. (B) Frequency characteristics resulting from adjustment of the device of one example of the present invention.

FIG. 5 is a block diagram of a conventional circuit.

FIG. 6A is an adjustment state diagram of a conventional element. (B) Frequency characteristics resulting from the adjustment of conventional elements.

FIG. 7A is an adjustment state diagram of a conventional element. (B) Frequency characteristics resulting from the adjustment of conventional elements.

FIG. 8A is an adjustment state diagram of a conventional element. (B) Frequency characteristics resulting from the adjustment of conventional elements.

[Explanation of symbols]

 11 Graphic Equalizer 12 Buffer Amplifier 13 Buffer Amplifier 14 Volume Control 15 Amplifier 16 Microcomputer (Control Means) 19 Attenuator

Claims (4)

[Claims] 1. A graphic equalizer that divides a reproduction frequency band into a plurality of continuous frequency bands and adjusts a gain by a predetermined amount for each frequency band, and detects the adjustment amount of each device. A control means, an attenuator provided on the front side of or immediately after the graphic equalizer, which is controlled by the control means to increase / decrease the on / off amount or the attenuation amount, and a volume control which is controlled by the control means. The graphic equalizer, wherein the control means calculates the adjustment amount of each detected element, and controls the attenuator and the volume control according to a result of the calculation. 2. The calculation is to add the positive adjustment side of the detected adjustment amount of each element, and the control is to turn on or attenuate the attenuator when the addition value exceeds a predetermined value. The graphic equalizer according to claim 1, wherein the amount is increased by a predetermined amount and the volume control is increased by a predetermined volume. 3. A graphic equalizer that divides a reproduction frequency band into a plurality of continuous frequency bands and adjusts the gain by a predetermined amount for each frequency band, and detects the adjustment amount of each device. The control means includes: a control means, an amplifier which is controlled by the control means to change a gain, and which is provided in front of or immediately after the graphic equalizer; and a volume control which is controlled by the control means to adjust a volume. , Calculates the detected adjustment amount of each element, and by the result of the calculation,
A graphic equalizer for controlling gain and volume control of the amplifier. 4. The calculation is to add a plus side of the detected adjustment amount of each element, and the control is to set the gain of the amplifier to a predetermined value when the added value exceeds a predetermined value. The graphic according to claim 1, wherein the volume control is increased by a predetermined amount and the volume control is increased by a predetermined volume.
equalizer.