JPH05122782A - Acoustic reproduction device - Google Patents

Abstract

PURPOSE:To realize the faithful acoustic reproduction by reducing the harmonic distortion to be generated from a speaker unit without distorting the output even when a signal which a speaker unit can not reproduce is inputted. CONSTITUTION:A generation of harmonic distortion due to the excess amplitude of a speaker unit 4 is prevented and the faithful acoustic reproduction can be realized by an enclosed speaker cabinet 5 with at least one plane, a high frequency pass circuit 3 taking the lowest resonance frequency of the speaker unit 4 fixed inside of the cabinet 5 as breaking frequency, and the speaker unit 4 mounted on the front surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound reproducing device such as a speaker system used for sound reproduction.

[0002]

2. Description of the Related Art In recent years, with the development of digital audio equipment such as compact disc players, it has become possible to realize signal transmission with a flat frequency characteristic from a low frequency range to a high frequency range, which was impossible in the analog audio era. As a result, a music signal including an ultra-low frequency component of 60 Hz or less, which has not been input until now, has been added to a sound reproducing device such as a speaker system which is a sound outlet. Therefore, recently, along with this, much research has been conducted on an audio reproduction device that extends the reproduction limit of the low frequency range, but the distortion generated at the time of reproduction due to a music signal containing an extremely low frequency range component is not so much considered. The current situation is that there are none.

A conventional sound reproducing device will be described below with reference to the drawings. As shown in FIG. 5, the conventional sound reproducing device is composed of a sealed speaker cabinet 1 and a speaker unit 2. The operation of the sound reproducing device configured as described above will be described below. First, an electroacoustic signal corresponding to a music signal to be reproduced is amplified by an amplifier or the like and input to the speaker unit 2 fixed to the closed speaker cabinet 1. The speaker unit 2 generates a driving force corresponding to the electroacoustic signal in the field unit, and operates the diaphragm to vibrate the air outside the sealed speaker cabinet 1 to generate an output sound pressure. Sound reproduction is being performed.

[0004]

However, in the above-mentioned conventional configuration, when an electroacoustic signal containing an ultra-low frequency component of 60 Hz or less is input, a nonlinear driving force is applied to the speaker unit 2. That is, in general, the lower limit of the reproducible frequency of the speaker unit 2 is determined by the lowest resonance frequency, and although it depends on the diameter of the diaphragm, it is about 60.
It is around Hz, which corresponds to a very low frequency component in a music signal. Below this minimum resonance frequency, the output sound pressure sharply decreases as shown in FIG. 6 and the amplitude of the speaker unit 2 itself becomes maximum even though the desired sound reproduction cannot be performed. If more input is applied, the amplitude limit of the speaker unit 2 will be exceeded, and it will not be possible to obtain a driving force proportional to the input, and a non-linear driving force will work. As a result, as shown in FIG. 7, in the reproduced output sound pressure frequency characteristics, many unnecessary second and third harmonics are generated in addition to the fundamental wave, and these become harmonic distortion and are superimposed, resulting in total output sound. The pressure characteristics deteriorate. Therefore, there is a problem that desired acoustic characteristics cannot be obtained.

The present invention solves the above-mentioned conventional problems. Even when a signal including an extremely low frequency component below the lowest resonance frequency that cannot be reproduced by a speaker unit is input,
An object of the present invention is to provide a sound reproducing device capable of realizing high fidelity sound reproduction by reducing the harmonic distortion generated by the non-linear driving of the speaker unit due to excessive amplitude.

[0006]

In order to achieve this object, the sound reproducing apparatus of the present invention cuts off a sealed speaker cabinet having at least one plane and a resonance frequency lower than the lowest resonance frequency of a speaker unit fixed therein. It is composed of a high frequency band pass circuit having a frequency and a speaker unit for reproducing the output.

[0007]

According to the present invention, in the above-mentioned structure, the high-frequency band pass circuit removes an ultra-low frequency band component that cannot be reproduced by the speaker unit, whereby the speaker unit is not driven non-linearly by an excessive amplitude and the higher harmonics are generated. It is possible to realize sound reproduction without distortion.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the sound reproducing device of this embodiment has a high-frequency band pass circuit 3 and a minimum resonance frequency of 60 Hz.
Speaker unit 4, closed speaker cabinet 5
It is composed of.

The operation of the sound reproducing apparatus configured as described above will be described below. First, the electroacoustic signal corresponding to the music signal to be reproduced is input to the high frequency band pass circuit 3, as shown in FIG. Since the cutoff frequency and the cutoff characteristic of the high frequency band pass circuit 3 are matched with the lowest resonance frequency of the speaker unit 4, the cutoff frequency is set to 60 Hz and the cutoff characteristic is set to 12 dB / Oct by the variable capacitor 6 and the coil 7. As shown in FIG. 3, the output of the high frequency band pass circuit 3 has a gain of −12 below the cutoff frequency.
Although it is input to the speaker unit 4 as a signal attenuated by dB / Oct, the amplitude characteristic is lowered below the minimum resonance frequency because a component below the minimum resonance frequency of the speaker unit 4 is not included. Therefore, the speaker unit 4 can be driven without being subjected to excessive amplitude modulation due to an extremely low frequency component of 60 Hz or less that cannot be reproduced. As a result, as shown in FIG. 4, it becomes possible to take out the output sound pressure from the speaker unit 4 with little second and third harmonic distortion generated by the excessive amplitude modulation.

As described above, according to the present embodiment, the speaker unit 4 cannot be reproduced by the high frequency band pass circuit 3 having the cutoff frequency equal to or lower than the lowest resonance frequency of the speaker unit 4 and the speaker unit 4 reproducing this output. Even if an electroacoustic signal including an ultra-low frequency component equal to or lower than the lowest resonance frequency is input, the speaker unit 4 is not nonlinearly driven, and it is possible to extract an output sound pressure without harmonic distortion generated thereby.

In the above embodiment, the cutoff frequency of the high frequency band pass circuit 3 is set to 60 Hz, but the cutoff frequency is set at a proper time by adjusting the variable capacitor 6 according to the lowest resonance frequency of the speaker unit 4 to be connected. do it. Also, the high frequency band pass circuit 3 has a cutoff characteristic of 12 dB / Oct.
Set to, but the cutoff characteristics are connected to the speaker unit 4
It goes without saying that it may be varied according to the sound pressure characteristics of the.

[0012]

As is apparent from the above embodiments, the present invention provides a closed type speaker cabinet having at least one plane, and a high frequency band passage having a cutoff frequency lower than the lowest resonance frequency of the speaker unit fixed therein. With the circuit and the speaker unit mounted on the front of the closed speaker cabinet that reproduces this output, even if a signal containing an ultra-low frequency component below the lowest resonance frequency that cannot be reproduced by the speaker unit is input, the speaker unit will be over-excited. It is possible to realize an excellent sound reproducing device that does not cause harmonic distortion without causing non-linear drive.

[Brief description of drawings]

FIG. 1 is a perspective view of a sound reproducing device according to an embodiment of the present invention.

FIG. 2 is a high-frequency band pass circuit diagram used in the embodiment.

FIG. 3 is a diagram showing an output characteristic of a high frequency band pass circuit and an amplitude characteristic of a speaker unit according to the embodiment.

FIG. 4 is an output sound pressure frequency characteristic diagram of the sound reproducing device of the embodiment.

FIG. 5 is a perspective view of a conventional sound reproducing device.

FIG. 6 is a diagram showing an output sound pressure characteristic and an amplitude characteristic of the sound reproducing device.

FIG. 7 is a diagram showing an output sound pressure frequency characteristic of the same sound reproducing device.

[Explanation of symbols]

 3 High-frequency band pass circuit 4 Speaker unit 5 Sealed speaker cabinet 6 Variable capacitance capacitor 7 Coil

Claims (3)

[Claims] 1. A hermetically-sealed speaker cabinet having at least one plane, a high-frequency band passage circuit fixed inside the hermetically-sealed speaker cabinet and having a cutoff frequency equal to or lower than a minimum resonance frequency of a speaker unit, and the hermetically-sealed speaker cabinet. A sound reproducing device that is mounted on the front surface of the speaker and that includes a speaker unit that reproduces the output of the high-frequency band pass circuit. 2. The sound reproducing apparatus according to claim 1, further comprising control means capable of varying the cutoff frequency of the high frequency band pass circuit. 3. The sound reproducing device according to claim 1, wherein the high frequency band pass circuit is composed of a variable capacitance capacitor and a coil.