JPH03240307A - Acoustic equipment - Google Patents

Abstract

PURPOSE:To obtain a desired sound quality characteristic by reading out music data designated by a storage means, giving the data to a digital signal processing circuit and giving the data set by an input means to the digital processing circuit. CONSTITUTION:An audio signal selected by an input changeover circuit 1 is given to a digital signal processing circuit 3 via an A/D converter circuit 2 and divided into plural frequency bands and the frequency characteristic of each band is digitally processed. The data of the frequency characteristic of each band decided in advance is stored corresponding to a music source in a preset memory 20 and a CPU 22 reads the data of the music source designated by a key input circuit 8 from the memory 20, given to the digital signal processing circuit 3 and the frequency characteristic is processed. Then the data set by the key input circuit 8 is given to the digital signal processing circuit to vary the frequency characteristic. Thus, the sound quality characteristic of the desired music source is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an audio device that divides the frequency band of an audio signal into a plurality of frequency bands and changes the frequency characteristics in each band by digital processing.

(B) Prior Art With the recent shift to Hi-Fi audio equipment, graphic equalizers have been installed in audio equipment such as car stereos.

This graphic equalizer divides the frequency band of an audio signal into a large number of frequency bands, ie, channels, and changes the frequency characteristics for each channel, so that the frequency characteristics over all bands can be changed arbitrarily.

By the way, in this graphic equalizer, as disclosed in Japanese Patent Publication No. 1-28523, for example, data corresponding to various frequency characteristics (separated by music source) to be obtained by the graphic equalizer is stored in advance. There are devices that allow arbitrary frequency characteristics to be given simply by setting them in a memory or the like and selecting one of the preset data when necessary.

(c) Problems to be Solved by the Invention In the preset type graphic equalizer as described above, the selected frequency characteristics are fixed and cannot be finely adjusted by the user. Therefore,
With this, it is not possible to obtain the desired sound quality characteristics of the music source in a space with severe acoustic characteristics such as inside a car.

(d) Means for Solving the Problems The audio device of the present invention includes a digital signal processing circuit that divides the frequency band of an audio signal into a plurality of frequency bands and changes the frequency characteristics in each band through digital processing; the storage means for storing data on the frequency characteristics of each of the bands predetermined corresponding to the source; the designation means for specifying the music source stored in the storage means; After executing the first mode, the data of the music source designated by the input means for arbitrarily varying the data is read from the storage means and the data based on the data is given to the digital signal processing circuit, and the input means and control means for executing a second mode in which set data is provided to the digital signal processing circuit.

(E) Function The present invention is configured as described above, and after setting the frequency characteristics of each band according to the music source, the frequency characteristics of each band can be changed arbitrarily from that state.

(f) Example Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a block diagram of the audio device of the present invention, in which (1) is an input switching circuit for selecting one of the audio signals from a device such as a radio receiver or a cassette tape recorder, and (2) is a block diagram of the audio device of the present invention. The audio signal selected by the input switching circuit (1) is input to f.

This is an A/D conversion circuit that performs A/D conversion at a sampling frequency of . (3) is a digital signal processing circuit that processes the digital signal from the A/D conversion circuit (2), and as shown in FIG.
It has a seven-stage digital band-pass filter composed of filters that divide the frequency band of the audio signal into seven. In addition, one band pass filter (BPF
I) includes four delay elements (D) and five coefficient multipliers (K, , , , 3, , KS, as disclosed in, for example, Japanese Unexamined Patent Publication No. 62-291212). ) and the adder (Add), and by changing the multiplication coefficient of this coefficient multiplier, the values of the center frequency (fO), gain (G), and filter sharpness (Q) can be changed. . Incidentally, each multiplication coefficient can be determined by the formula shown in FIG. 9 (different depending on whether the gain is positive or negative), and this calculation is performed by the CPU (22) described later. (4), (4), and (4) are D/A conversion circuits that convert the digital signal from the digital signal processing circuit (3) into an analog signal. (5), (5), (5
) is an amplifier that amplifies the output signals of the D/A conversion circuits (4), (4), (4), and (6) (6)... are speakers. (7) is a display device, which is a dot matrix type liquid crystal display as shown in FIG. (8) is a key input circuit, which also includes a parameter selection key (9), a parameter change key (10), an input selection key (11), a preset key (12) and a source selection key (13), as shown in FIG. to (19). (20) is RO
Music sources (here, jazz, hops, rock, disco, po-cal,
The data of the center frequency (fO), gain (G), filter sharpness (Q) of each band corresponding to the music (classic, stadium) and the multiplication coefficient of the digital signal processing circuit (3) are input using the source selection key (13). (19) is stored. (21) is a data memory consisting of RAM; (22) is a CPU, which exchanges data with the data memory (21) and preset memory (20) according to a program written in a program memory (23) consisting of ROM; It also controls the input switching circuit (1), display device (7), and key input circuit (8) via the IO boat (24). FIG. 3 shows a flowchart of the main part of the program written in the program memory (23), and the operation will be explained below based on this. First, when one of the audio signals selected by the input switching circuit (1) is being played back, the source selection key (13) is pressed after the preset key (12) is operated.
) to (19) is operated, the CPU
(22) reads the center frequency (fo), gain (G), filter sharpness (Q) data and multiplication coefficient of each band corresponding to the selected source from the preset memory (20), and ), gain (G), and filter sharpness (Q) are stored in the data memory (21), and the multiplication coefficient is stored in the digital signal processing circuit (3).
) (Steps S-1 to S-3). This causes the digital signal processing circuit (3) to equalize the selected music source.

The data memory (21) has two areas for storing each parameter; one area stores data read from the preset memory (20), and the other area stores the digital signal processing circuit (3).
) (here, the same data is stored). Here, for example, when the source selection key (17) is operated and vocal is selected, the multiplication coefficient regarding vocal is changed to the digital signal processing circuit (
3) is given.

Then, the CPU (22) displays the image shown in FIG.
Gain data is read from the other area, and the gain of each frequency band is displayed on the display device as shown in FIG. 5 (display 2) (steps S-4, S-5). After this, CPU (22
) is the preset key (12) and source selection key (1
3) to (19) are monitored, and when the preset key (12) is operated, steps S-2 to S-5 described above are performed.
The process is repeated (steps S-6 and S-7). Further, if any of the source selection keys (13) to (19), for example, the source selection key (13) in this case is operated without operating the preset key (12), the CPU
(22) is the center frequency (
fo), gain (G), and filter sharpness (Q) are read out from the respective areas of the data memory (21) and displayed on the display device (7) as shown in FIG. 6 (display 3) (step 5-8). ). In the display of FIG. 6, the numerical values of each parameter on the left side are unchanged at predetermined poocal values, and the numerical values of each parameter on the right side are processed by the digital signal processing circuit (3). It is a value.

In this state, the CPU (22) presses the parameter key (
Each time you operate step 9), the numerical value of each parameter displayed on the right side of the display device (7) will blink in sequence, and the blinking numerical value will be displayed by pressing the parameter change key (10).
) (step 5-9).

For example, when the gain (G) is changed from +10 dB to +15 dB, the CPU (22) displays the display as shown in FIG. When (13) is operated, &ffl of each changed parameter is substituted into the formula shown in FIG.
), and the data of each changed parameter is stored in the other area of the data memory (21) (step S-
10-12). This allows the digital signal processing circuit (
In step 3), equalization is performed using the changed parameter values. Also, the CPU (22) again
The gain for each frequency band is displayed in the display group @(7) as shown in FIG. 8 (display 5), and the process returns to step S-6 (step S-13). In this display, the predetermined vocal gain position of the first-stage bandpass filter (BPFI) is left, and the extent to which the gain has been changed from that position is shown.

In the above explanation, the case where the source selection key (13) was operated was explained, but each source selection key (13)
(19) correspond to each bandpass filter of the digital signal processing circuit (3), and by operating any of the source selection keys (13) to (19), the numerical value of each parameter of the corresponding bandpass filter can be changed. It is possible to change.

(G) Effects of the Invention The present invention is capable of arbitrarily changing the frequency characteristics of each band from that state after setting the frequency characteristics of each band according to the music source as described above. The desired sound quality characteristics of the sound flux source can be obtained even when used in a space with severe acoustic characteristics conditions.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the audio device of the present invention, and FIG.
Similarly, the main part block diagram of the digital signal processing circuit, Part 3
This figure is a flowchart of the main part of the program written in the program memory, and FIGS. 4 to 8 are front views showing each display mode of the display device. Figure 9 shows
FIG. 3 is a diagram showing a mathematical formula for calculating a multiplication coefficient. (3)...Digital signal processing circuit, (7)...Display device, (8)...Key input circuit, (20)...Data memory, (21)...Preset memory, (22)...
)...CPU, (23)...Program memory, (2
4)...IO boat.

Claims (1)

[Claims] (1) A digital signal processing circuit that divides the frequency band of an audio signal into multiple frequency bands and changes the frequency characteristics in each band through digital processing, and a frequency of each band that is predetermined according to the music source. storage means for storing characteristic data; designation means for designating the music source stored in the storage means; input means for arbitrarily varying the frequency characteristics of each of the bands; and designation by the designation means. After executing a first mode in which data of the music source that has been set is read from a storage means and data based on the read data is provided to the digital signal processing circuit, a second mode in which data set by the input means is provided to the digital signal processing circuit; An acoustic device comprising: a control means for executing a mode.