JPH01149697A - Bass emphasized sound reproducing device - Google Patents

Abstract

PURPOSE:To make sounds in which low-pitched sounds are excellently reproduced enjoyable by providing a low-pass filter which passes only the low-band component of inputted and branched signals and a musical interval converting circuit which converts the frequency of the output of the filter to a half. CONSTITUTION:Signals S1 inputted to an input terminal 1 are branched into two parts by means of a branching means 7. A 1st output of the two parts is inputted to a 1st input terminal of an adder 8 as it is. On the other hand, a 2nd output is converted into output signals S2 of low-pitched sound components only by a 1st low-pass filter (LPF) 4 which passes low-voice range components only. The signals S2 are converted into signals S3 whose frequency is the halt of that of the input signals S2 by means of a musical interval converting circuit 5 which converts the frequency of its output signal to the half of that of its input signal. In other words, the signals S3 are signals which are produced by shifting the low-band components contained in the signals S1 inputted to the input terminal 1 to the lower band side by one octave. The output signals S3 of the circuit 5 are inputted to a LPF 6 where low-voice range components of the signals S3 are sharply cut off.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention particularly relates to a heavy bass playback device that improves the bass playback performance of small and simple audio equipment such as portable radio-cassette players and car stereos.

BACKGROUND OF THE INVENTION In recent years, with the release of digital sources, the reproduction of deep bass has attracted attention. The description will be given below with reference to the drawings.

A conventional example is shown in FIG. In FIG. 6, an output signal S1 from a reproducing device 1 such as a radio or a tape deck is power-amplified by an amplifier 2 to become a signal s2, which is electroacoustically converted by a speaker 3 to reproduce a sound wave M.

FIG. 7 shows the frequency characteristics of the output signal s1 of the reproducing device 1. In FIG. 7, the horizontal axis represents frequency, and the vertical axis represents voltage level, where the frequency characteristic of the output signal s1 is N1, and the low cutoff frequency kf is determined by the performance of the head of the playback device 1. Therefore, in a playback device, the area L1 becomes wider, and as a result, the speaker 3 cannot play back that area L1 even though it has the ability to play it.

As a countermeasure, there has been a low-pitched sound quality adjustment function called tone control, but this has the problem of increasing noise components.

On the other hand, it is also related to the low-frequency components contained in the source itself that is reproduced by the playback device 1, and it is theoretically impossible to reproduce heavy bass using the conventional example shown in Fig. 6 from a source that does not include low-frequency ranges. It was impossible. Furthermore, due to the low-frequency characteristics determined by software conditions such as the presence or absence of low-frequency components of the source reproduced by the reproduction device 1, the low-frequency range could not be reproduced even though the speaker 3 had the reproduction capability.

In view of the above problems, the present invention creates a deep bass component without increasing noise components by processing the bass component of the output signal when the output signal of the playback device 1 does not include a deep bass component. It is an object of the present invention to provide a heavy bass reproduction device that can reproduce deep bass sounds.

Means for Solving the Problems In order to solve the above problems, the present invention provides a branching means for branching an input signal from an input terminal into two, and a first branching means for passing only the low frequency component of one of the two branched output signals. A low-pass filter (hereinafter abbreviated as the first LPF) is inputted with the output signal of the first LPF, and the frequency of the input signal is set to half the frequency of the output signal. a pitch conversion circuit, and a first LPF that passes only the low frequency component of the output signal of the pitch conversion circuit;
The second LPF has a steep cut-off characteristic for high-frequency components, and means for electroacoustic converting the output signal of the second LPF and the other signal of the branching means, either individually or by adding them together. There is.

Effect The present invention applies pitch conversion to half the frequency of the low-frequency components contained in the input signal using an LPF and a pitch conversion circuit that halves the frequency of the output signal relative to the frequency of the input signal, thereby increasing the noise component. This makes it possible to reproduce deep bass sounds without any noise.

Embodiment FIG. 1 shows a block diagram of a heavy bass reproduction device according to a first embodiment of the present invention.

The good signal S1 input to the input terminal 1 is branched into two by the branching means 7, and the first output thereof is directly sent to the adder 8.
is input to the first input terminal of. On the other hand, the second output is converted into an output signal S2 containing only bass components by a first LPF 4 that passes only the bass range. This LPF4
The band through which the signal passes will be explained with reference to FIG.

The high-frequency cutoff characteristic, that is, the low-frequency pass characteristic of the cutoff frequency f of the LPF 4 is shown as a characteristic H1, and the low-frequency component that passes through it is shown as a hatched area L4.

Then, the signal S2 is converted into a signal S3 whose frequency is half the frequency of the input signal S2 by the pitch conversion circuit 5, which halves the frequency of the output signal with respect to the frequency of the input signal. That is, the signal S is obtained by shifting the low frequency range included in the good signal S1 input to the input terminal 1 by one octave. The output signal S of the pitch conversion circuit 6 is then input to the LPF 6, which further sharply cuts off the low frequency range components.

The entire operation will be explained with reference to FIG. High-frequency cut-off characteristics of the cutoff frequency f of LPF6, that is, low-frequency pass characteristics'
f, denoted by H2, and the entire shaded area L of the low frequency range components through which it passes.
In addition, the low frequency pass characteristics of LPF4 shown in Figure 3 are shown by H4 with a broken line, and its LP, F4 and LPF6
The area of difference between the low frequency pass components is shown as fjr:L6. Since the main feature of the present invention lies in this region L6, it will be explained in more detail.

The reason why the low frequency pass characteristic is steep like the frequency characteristic H2 shown in Fig. 4 is that when the signal S1 input to the input terminal 1 contains an audio signal, the frequency of the audio signal is halved. This is the ninth step that prevents things from being perceived as distorted. For this purpose, LPF4 and LPF4 shown in Fig.
This can be achieved by setting both the low frequency pass characteristics of PF6 to the characteristics H2 shown in FIG. However, on the other hand, an LPF with a very steep cut-off characteristic has a disadvantage that the circuit configuration is complicated and the price is high. The other characteristic was set to a relatively gentle characteristic as shown in FIG. In order to reduce the digital noise and distortion generated in the pitch conversion circuit 6 shown in FIG.
is the characteristic of Hl shown in FIG.

Now, the deep bass generating function will be explained in detail using the frequency characteristic diagram shown in FIG. The pitch conversion circuit 5 changes the low frequency characteristic curve from characteristic N1 to characteristic N2.

Its cutoff frequency also moves by an octave from fl to 12. In other words, the components of region L2 can be reproduced.

Then, the output signal S4 of the LPFs is the second output signal S4 of the adder 8.
The signal S input to the input terminal and added by the adder 8
5, the power is amplified by the amplifier 2, and the signal is reproduced from the speaker 3.

FIG. 2 shows a block diagram of another embodiment of the invention. In this embodiment, the output signal of the LPF 6 is inputted to the amplifier 2.9 without going through the full adder, power amplified, and reproduced by the speaker 3.10.

In this case, a speaker 1° is required in addition to the conventional speaker 3, but the speaker 10 only needs to reproduce deep bass, and if it is a speaker dedicated to reproducing deep bass, generally called a Super Uno. good.

Similarly, the configuration of the pitch conversion circuit 5 only needs to be able to convert the frequency of the input signal by at least half, and a specific example is the one described in Japanese Patent Application Laid-Open No. 123895/1983.

Effects of the Invention As described above, the present invention provides a low-pass filter that passes only the low-frequency components of the input and branched signal, and a pitch conversion circuit that converts the output frequency of the low-pass filter to half the total frequency. Compared to the example, even with the same source and reproduction device, you can enjoy well-reproduced sound with good bass. In particular, it is an object of the present invention to provide an excellent deep bass reproduction device that can reproduce deep bass without distortion even when the source to be reproduced does not, in principle, contain deep bass, such as an AM radio broadcast or movie source. It is possible.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a deep bass reproduction device according to an embodiment of the present invention, Figure 2 is a block diagram showing an embodiment of the same location, Figures 3 and 4 are characteristic diagrams of LPF, and Figure 5 is A frequency characteristic diagram showing the effects of the present invention, FIG. 6 is a block diagram of a conventional example, and FIG. 7 is a frequency characteristic diagram of the conventional example. 1...Input terminal, 2...Amplifier, 3.
...Speaker, 4.8...I, PIC1
6... Pitch conversion circuit, 8... Adder. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 4 Shoulder Narashiki Figure 5 Dance voice answer Su ÷ Power

Claims (1)

[Claims] an input terminal, a branching means for branching a signal input to the input terminal into two, and a first signal inputting a first signal branched by the branching means and passing only a low frequency component of the first signal. a low-pass filter; a pitch conversion circuit that receives the output signal of the first low-pass filter as an input and is capable of making the frequency of the output signal at least half the frequency of the input signal; and the output signal of the pitch conversion circuit. is input, a second low-pass filter has substantially the same cutoff frequency as the first low-pass filter, and has a steep high-frequency cutoff characteristic, and the branched second signal and the second The signal obtained by adding the output signal of the low-pass filter, or the branched second signal and the second
A heavy bass reproduction device comprising means for separately electroacoustic converting the output signal of the low-pass filter.