JP2016001861A - Speaker system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a speaker system used in a high-fidelity stereoscopic sound field reproduction, especially to provide an enclosure (a case) having a sound effect of comfortable listening.SOLUTION: An enclosure (a case) in whole is formed of a wooden regular cube, whose inside is constituted of one speaker unit and an acoustic filter. A property of the acoustic filter in detail is attention to the fact that a regular porous body having a flute structure (a corrugated shape) that a cardboard as a foundation material has adapts to the acoustic filter. In further detail, the acoustic filter is excellent in moldability, has a pore diameter and 90% or more porosity and suppresses a standing wave considered to be generated by unnecessary vibration caused by a flow-through property (an oscillation attenuation property) of air (a sound wave) and an oscillation adjustment property thereof.

Description

    The present invention relates to a speaker system in high-fidelity three-dimensional sound field reproduction, and provides a speaker enclosure (housing) that is particularly comfortable to listen to.

    It is obvious that the basic configuration of the speaker system is an electrical acoustic conversion device using a combination of a speaker unit and an enclosure suitable for sound reproduction.

    The basic form of the speaker system, the enclosure that radiates only sound directly from the front of the speaker is called a sealed type, and prevents interference from the diffraction effect between the sound from the front of the vibration plate and the sound emitted from the back. be able to. As a feature, the air on the back side is sealed, and the movement of the diaphragm is suppressed and the efficiency is lowered, but the low resonance frequency (f0) is increased, and a stable bass can be obtained. However, if the enclosure is not rigid, unnecessary resonance is observed.

    It looks like a sealed enclosure (housing), but by installing a (duct) called an acoustic port on the front or rear surface, the sound pressure of the internal volume and the mass of air in the acoustic port (duct) part The minute causes Helmholtz resonance, which resonates at a half-resonant frequency and emits sound to the outside. When this radiated sound is higher than the anti-resonance frequency, it has the same phase as the sound radiated from the front surface of the vibration field plate. This phenomenon is called a phase inversion type or a bass reflex type because the phase is inverted. This type occupies much of the current speaker system. However, it is known that it lacks reverberation characteristics that are important for sound appreciation because it exhibits a characteristic that the attenuation of bass sound is faster than that of the sealed type.

    A backload horn type that belongs to the enclosure in a phase-inverted speaker system, radiates sound emitted from the back side adjacent to the front speaker and a long sound path instead of the duct adjacent to the front side of the speaker unit. is there. Since this type places importance on the low range, it is difficult to design reproduction of the mid range. In addition, it is necessary to devise measures for resonance of the sound path (horn) and removal of unnecessary high-frequency components. Since a longer sound path is required, the production cost increases.

    Therefore, the structural type of the enclosure (housing) of the present invention is an invention on the extension lines of the respective features of the sealed type, the phase inversion type, and the back load horn type. It is none other than evolving.

    The biggest problems in the present invention are: 1 playback frequency band, which is a basic condition for improving the performance of a speaker system, 2 flattening of response characteristics, 3 improving directivity sensitivity characteristics, 4 creating low distortion, and 5 transients Improvement of characteristics, 6 flattening of phase characteristics, 7 generation and removal of abnormal sounds and natural sounds, 8 improvement of allowable input efficiency.

    The acoustic engineering theory in the above speaker system is in the field of electronic and electromechanical engineering. From another point of view, the speaker system consists of a speaker unit that is driven by a diaphragm with an electrical signal and an enclosure that does not have an electrical element. A sound reproduction engineering theory with the characteristic function as an element can be considered.

    Conventionally, it is obvious that there are a sealed type and a phase inversion type if the enclosure is roughly divided. In the sealed type, the smaller the enclosure (housing), the higher the internal sound pressure of the back acoustic wave radiated from the speaker diaphragm in the enclosure (housing), so the vibration of the speaker unit is independent of the input signal. The efficiency will be reduced. The phase inversion type is more advantageous when the enclosure (casing) is manufactured with the same unit and volume as the sealed type, but the sound pressure of the bass is higher than that of the sealed type, but depending on the diameter and length of the duct. The low-frequency radiation effect disappears, and the transient characteristics deteriorate.

    Therefore, the present invention is different from the resonance phenomenon due to the acoustic port (duct), which is a feature of the phase inversion type, and all the pores of the flute occupying one half of the enclosure (housing) serve as a filter replacing the acoustic port. . The filter detects and suppresses sudden changes in the sound pressure level. Therefore, the sound energy balance in the reproduction band can be always kept flat. The radiated sound on the front surface is a direct sound in a directional manner, and the radiated sound in the rear enclosure has a sound field characteristic in all directions by passing through the flute.

    The current state of technological development in the above speaker system is focused on the related functions of the enclosure (case) and its design rather than on the function development of the unit. Various foundation materials are being developed. However, they are merely following the conventional sealed and phase-inverted sound reproduction methods, and are not based on novel and evolved theories.

    Therefore, an object of the present invention is to examine and solve the above-mentioned problems.

    The sound reproduction effect in the speaker system of the present invention is that the enclosure structure is important for sound production. First, one half of the air chamber at the rear of the housing is opened, which is a closed type difficulty. The speaker unit was operated without lowering the vibration efficiency due to the increase in sound pressure. In addition, the remaining air chamber (1/2) is made of corrugated cardboard with a high porosity, and the sound flow similar to the principle of the phase-inverted acoustic port is obtained by measuring the sound pores through the pores and measuring the vibration absorption characteristics. The decay time can be controlled. Therefore, according to the present invention, the sound radiated from the acoustic filter behind the enclosure (housing) is diffused by the flute and thus becomes an indirect sound exhibiting an omnidirectional characteristic in which the bass is amplified. The radiated sound from the front has directivity as a direct sound and supports mid-range sound in terms of hearing. The biggest purpose of the speaker system development is the ideal sound field reproduction in the speaker system and the expressive power of the sound (timbre, tone, faithful reproduction of various instruments). More specifically, the appearance and size of the enclosure (housing) vary, but in the internal structure, the regular cube is harmful to the sense of hearing because the sound radiated from the back of the speaker from the back of the unit is acoustic with an equal reflectance. It was said that the occurrence of standing waves could not be eliminated. In the present invention, the occurrence of internal standing waves can be eliminated by corrugated cardboard (flute structure) even though the outer appearance and the internal structure are regular cubes.

It is explanatory drawing which showed the implementation method of the enclosure (enclosure) in a speaker system.

It is sectional drawing of the enclosure (enclosure) Example of the apparatus of this invention in a speaker system.

The enclosure (housing) in the speaker system of the present invention can be applied to an indispensable use as an unprecedented audio apparatus by an acoustic filter comprising a cardboard flute attached to the enclosure.

1 Enclosure
2 Speaker unit 3 Acoustic filter 4 Protective net

Claims (4)

    The present invention relates to a speaker system for reproducing a high fidelity three-dimensional sound field, and provides a speaker system using an enclosure having a sound effect that is particularly comfortable to listen to. The entire case is made of a regular wooden cube, and a single speaker unit is mounted on the front. The rear surface is a full opening and the front half of the total volume is an air chamber. The remaining rear half is an enclosure (housing) made of an acoustic filter formed of cardboard.     Corrugated cardboard, which is the cornerstone of an acoustic filter, is formed of a base paper called a liner and a core called a flute (wave shape). The corrugated flute structure has a true porosity of 90% or more. More specifically, it has excellent formability, can control the pore diameter and porosity, and has a relatively high dimensional accuracy. In addition, we focused on the fact that unnecessary vibration was suppressed by the air (sound wave) flow-through property (vibration damping property) and its vibration damping characteristics. The center of the side cross section of the shape of the acoustic filter according to claim 2 is thin and has a stepless curved shape toward the outside. The sound radiated from the speaker unit tends to radiate in the high range as it gets closer to the center, and the sound range is lower in the periphery. .     The object of the acoustic filter of the present invention is to control the total emission of the rear sound, which is the principle of the rear open type, by corrugated cardboard. Therefore, all the base materials which can be controlled by the pore diameter and the porosity of the porous body corresponding to the acoustic filter made of corrugated cardboard are included in the scope of the claims of the present invention. In addition, the adoption of the foundation material includes a single or multiple combinations.

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