JPS5890897A - Acoustic reproducer - Google Patents

Abstract

PURPOSE:To obtain a device which can automatically control the roudness characteristics most suitably in response to an acoustic signal, by separating the acoustic signal into low, intermediate and high frequency components and controlling the level in response to the level of the intermediate frequency component. CONSTITUTION:An acoustic signal is separated into low, intermediate and high frequency components, and the level of each frequency component is controlled depending on whether high or low the level of the intermediate frequency component. For example, the acoustic signal applied to an input terminal 18 is separated into low, intermediate and high frequency components at a low pass filter 1, an intermediate pass filter 2, and a high pass filter 3, and each component is inputted to boost/cut filters 11, 12, comparison circuits 4, 5 and a level detection circuit 13. The comparison circuit 4 compares the intermediate and low frequency components, and an output in response to the level difference is generated, the intermediate and high frequency components are compared at the comparison circuit 5, and an output is given. Limit voltage generating circuits 14, 15 compare the output of the comparison circuits 4, 5 with that of the level detection circuit 13.

Description

[Detailed description of the invention] The present invention relates to a sound reproduction device.

Conventional sound reproduction devices have the disadvantage that the acoustic characteristics are controlled according to the sound volume, and only constant acoustic characteristics are exhibited for any audio signal.

The present invention is capable of controlling the levels of each of the low and high frequency components according to the level difference between the midrange frequency component and the low and high frequency components of an acoustic signal, and the level of the midrange frequency component. This provides a sound reproduction device that eliminates the above-mentioned conventional drawbacks, and one embodiment thereof will be described below with reference to the drawings.

In Figure 1, (1) is a low-pass filter (hereinafter referred to as LP).
F), (2) is a middle pass filter (hereinafter referred to as BPF).
, (3) are high-pass filters (hereinafter referred to as HPF), and these filters (1) to (3) separate the acoustic signal into low, middle, and high frequency components. Separation means are configured. (4) is the LPF (1)
A comparator circuit that compares the output of BPF (
i) is a comparison circuit that compares the output of the HPF (s) and the output of the BPF (ri), and these comparison circuits (4)
(6) is a pair of detection circuits (6) as shown in Figure 2.
(7), a pair of integrating circuits (8) and (9), and a comparator (a). (2) is the LPF (
1) Low-frequency boost/cut filter that increases/decreases the output of
斡 is a high-frequency boost/cut filter that increases or decreases the output of the HPF (3). The characteristics of the low-frequency boost/cut filter are shown in Figure 4, and the characteristics of the high-frequency boost/cut filter are shown in Figure 4. They are shown in Figure 6. (
2) is a level detection circuit to which the output of the BPF (2) is input, and this level detection circuit (2) detects the level of the middle frequency component. α◆ is a control voltage generation circuit into which the outputs of the comparison circuit (4) and the level detection circuit (to) are input and generates a control voltage for the low-frequency boost/cut filter αCHIN; (G) is the comparison circuit (6) and a control voltage generation circuit which receives the output of the level detection circuit @aS and generates a control voltage for the high-frequency boost/cut filter (2), and ξ is a control voltage generation circuit Q4 (2).
) is composed of a comparator and a voltage generator (b), as shown in FIG. Note that (2) is an input terminal, and (to) is an output terminal.

In the above configuration, the acoustic signals applied to the input terminal (to) are tPF (r), BPF (z), HP
F (3) separates the frequency components into low, mid, and high frequency components, and the low frequency components are sent to the low boost/cut fill filter (b) and comparison circuit (4), while the mid frequency components are sent for comparison. The high frequency components are input to the circuit (4) (&) and the level detection circuit (to), and the high frequency boost/cut filter and comparison circuit (5), respectively. The comparison circuit (4) compares the mid-range frequency component and the low-range frequency component and generates an output according to the level difference, and the comparison circuit (5) compares the mid-range frequency component and the high-range frequency component. and generates an output according to the level difference. On the other hand, the level detection circuit (to) detects the level of the mid-range frequency component and generates an output accordingly. The control voltage generation circuit (b) includes a comparison circuit (4).
) and the output of the level detection circuit (2) are compared, and a control voltage corresponding to the difference is applied to the low-frequency boost/cut filter (b).1. This controls the dynamic low frequency and component levels. In addition, the control voltage main circuit (2) compares the output of the comparator circuit (5) and the output of the level detection circuit (to) and applies a control voltage corresponding to the difference to the high-frequency boost/cut filter (2). The level of the high frequency component is controlled by applying ξ.

FIG. 6 shows an example of the sound reproduction characteristics of the sound reproduction device having the above configuration. This is known from the well-known isosensitivity curves of Flexure Munson and Robinson-Duffdson regarding the human hearing characteristics, as shown by the solid line (A) (when the sound pressure level is low, the midrange On the other hand, when the sound pressure level of the low range' and high range is relatively thick as shown by the broken line (b) (and when the sound pressure level is medium, as shown by the solid line f), the sound pressure level of the low range and high range is The sound pressure level in the high range is relatively large as shown in the dashed line), and the solid line (
When the sound pressure level is high as shown in (e), the sound pressure levels in the low and high ranges are made relatively similar to the middle range as shown by the broken line (e).

As explained above, the sound reproduction device according to the present invention! ζ
According to the method, the level of each of the low and high frequency components is controlled according to the level difference between the midrange frequency component and the low and high frequency components of the acoustic signal, and the level of the midrange frequency component. As a result, the loudness characteristics can be automatically controlled to the optimum state according to the acoustic signal.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a circuit block diagram of an audio reproduction device, FIG. 2 is a circuit block diagram of a comparison circuit, FIG. 8 is a circuit block diagram of a control voltage generation circuit, and FIG.
Figure 6 is an explanatory diagram of the characteristics of the low-frequency boost/cut filter, and Figure 6 is an explanatory diagram of the characteristics of the high-frequency boost/cut filter.
The figure is an explanatory diagram of the sound reproduction characteristics of the sound reproduction device. (1)...low pass filter, (ri...middle pass filter, (3)...high pass filter, (4), (
5)...Comparison circuit, cap [...boost/cut filter, (2)...level detection circuit, Q4)...control voltage generation circuit agent Yoshihiro Morimoto Figure 1 Figure 2 L- ＋＋＋ −” Figure 4 Figure 5 Figure 6 Shutangshi CHx)

Claims (1)

[Claims] 1. Separation means for separating the acoustic signal into low, middle, and high frequency components, and a boost/capto filter that individually increases or decreases the low and high frequency components from the separation means;
a comparison circuit that separately compares the level of the mid-range frequency component from the separating means and the levels of the low-range and high-range frequency components; a level detection circuit that detects the level of the mid-range frequency component from the separating means; A control circuit is provided which separately controls each of the boost/cut filters using the output of the level detection circuit and the output of each of the comparison circuits, and the level of the mid-range frequency component and the low-range and high-range frequency components of the acoustic signal is adjusted. A sound reproduction device configured to control the level of each of the low and high frequency components according to the difference and the level of the midrange frequency component.