JPS62232298A - Very low-frequency sound reproducing device - Google Patents

Abstract

PURPOSE:To reproduce a very low-frequency sound by providing a low pass filter for passing through only the low frequency component of the output signal of a reproducing device and a musical interval converting circuit for converting the frequency of the output of the low pass filter to a half. CONSTITUTION:The output signal S1 of the reproducing device is branched into two by a branching means 7 and the first output is directly inputted to the first input end of an adding means. The second output is converted into the output signal S3 only of the low frequency component by the LPF 4 for passing only the low frequency. The signal S3 is converted to the signal S4 of the frequency half of the frequency of the input signal S3 by the musical interval converting circuit 5 for making the frequency of the output signal a half of the frequency of the input signal. Namely, the low frequencies included in the signal S4 and the output signal S1 of the reproducing device 1 are lowered by an octave. In this manner, the signal of the low frequency is lowered and moved by the octave, thereby it can be converted to the signal of a very low-frequency sound component.

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. This will be explained below with reference to the drawings.

A conventional example is shown in FIG. In FIG. 4, eight output signals from a reproducing device 1 such as a radio or a tape deck are power-amplified by an amplifier 2 to become a signal S2, which is converted into an electroacoustic signal by a speaker 3 to reproduce a sound wave M.

FIG. 5 shows the frequency characteristics of the output signal S1 of the reproducing device 1. In FIG. 5, the horizontal axis shows the frequency, the vertical axis shows the voltage level, the frequency characteristic of the output signal S1 is N1, and the low cutoff frequency determined by the performance of the head of the playback device 1 is fl. , the region that is not reproduced in the low frequency range is indicated by Ll.

This area L1 that is not reproduced in the low frequency range is wide in a playback device with a simple configuration, and as a result, the speaker 3 cannot reproduce this area L1 even though it has the ability to reproduce it.

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. 4 from a source that does not include low-frequency ranges. It was impossible.

Problems to be Solved by the Invention The problems of the conventional method are the low frequency characteristics determined by the output signal S1 of the reproducing device 1, that is, the input signal of the amplifier 2, that is, the hardware conditions such as the head characteristics of the reproducing device 1. 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.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention includes a reproducing device and a low-pass filter (hereinafter abbreviated as LPF) that passes only the low frequency component of one of the two-branched output signals of the reproducing device. , a pitch conversion circuit which inputs the output from the low-pass filter and halves the frequency of the output signal with respect to the frequency of the input signal, and separately converts the output signal of the pitch conversion circuit and the other branched signal, Alternatively, the configuration includes means for electroacoustic conversion of the added signal.

Function The present invention applies pitch conversion to half the frequency of the low-frequency component included in the output signal of the playback device using an LPF and a pitch conversion circuit that halves the frequency of the output signal with respect to the frequency of the input signal. It is designed to be able to reproduce deep bass sounds.

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

The output signal S1 of the reproducing device 1 is branched into two by the branching means 7, and the first output thereof is directly inputted to the first input terminal of the adding means. On the other hand, the second output is an output signal S3 containing only low-frequency components by LPF4 that passes only low-frequency components.
is converted to Then, if the signal S≠, the pitch conversion circuit 5 which halves the frequency of the output signal with respect to the frequency of the input signal converts it into a signal S4 whose frequency is half the frequency of the input signal S3. That is, the low range included in the signal S4 and the output signal S1 of the reproducing device 1 is shifted lower by an octave. In other words, by moving the low frequency component signal an octave lower, it can be converted into a heavy bass component signal.

This will be explained in more detail using the voltage level frequency characteristic diagram shown in FIG. The pitch conversion circuit 6 changes the low frequency characteristic curve from characteristic N1 to characteristic N2, and its cutoff frequency also moves by an octave from fl to f2. In other words, the components of region L2 can be reproduced.

The output signal S4 of the pitch conversion circuit 5 is input to the second input terminal of the adder 8, becomes a signal S5 added by the adder 8, is power amplified by the amplifier 2, and is reproduced from the speaker 3.

FIG. 3 shows a block diagram of another embodiment of the invention.

In this embodiment, the output signal of the pitch conversion circuit 5 is input to an amplifier 6 without going through an adder, and is amplified in power and reproduced by a speaker 7. In this case, a speaker 7 is required in addition to the conventional speaker 3, but this speaker 7 only needs to reproduce deep bass sounds, and it is sufficient if it is a speaker dedicated to playing deep bass sounds, generally called a Super Uno. .

Note that the pitch conversion circuit 5 halves the frequency of the output signal with respect to the frequency of the input signal, but this is not a half but a 1/
This is because if the pitch is set to 3rd grade, the pitch changes, causing a sense of discomfort, but if it is set to half, the pitch is lowered by an octave, which does not cause any sense of discomfort. In addition, in actual circuit design or auditory sense, it is sufficient to obtain the desired low pitch by halving the frequency and lowering it by an octave. It is okay to lower it.

The pitch conversion circuit 5 may be configured as long as it can convert the frequency of the input signal by at least half, and a specific example is the one described in Japanese Patent Application No. 59-245141.

Effects of the Invention As described above, the present invention has the advantage of providing a low-pass filter that passes only the low-frequency components of the output signal of the playback device, and a pitch conversion circuit that converts the frequency of the output of the low-pass filter to half. In comparison, even with the same source and playback device, you can enjoy well-reproduced sound with good bass. In particular, it is possible to provide an excellent deep bass reproduction device that can reproduce deep bass 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.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a heavy bass reproduction device according to an embodiment of the present invention, FIG. 2 is a voltage level frequency characteristic diagram showing the effects of the present invention, and FIG. 3 is a block diagram showing an embodiment of the same. FIG. 4 is a schematic diagram of the conventional example, and FIG. 6 is a voltage level frequency characteristic diagram of the conventional example. 1...--Reproducing device, 2, 6...... Amplifier,
3,7...Speaker, 4...LPF,
s...Pitch conversion circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Picture fungus Σ5th
figure

Claims (3)

[Claims] (1) A playback device that plays back an analog signal, a branching unit that branches the analog signal, and a low-pass input that receives a first signal branched by the branching unit and that passes only the low frequency range of the first signal. a filter, a pitch conversion circuit that receives the output signal of the 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 and the branched pitch conversion circuit. A deep bass reproduction device comprising: a signal obtained by adding a second signal; or means for individually electroacoustic converting the output signal of the pitch conversion circuit and the second signal. (2) The means for electroacoustic conversion includes an adder that adds the output signal of the pitch conversion circuit and a second signal branched into two, an amplifier that inputs the output of the adder, and The deep bass reproduction device according to claim 1, further comprising a speaker for input. (3) The means for electroacoustic conversion includes a first amplifier and a first speaker which receive the output signal of the pitch conversion circuit, a second amplifier and a second speaker which receive the second signal branched into two. A heavy bass reproduction device according to claim 1, comprising a speaker.