JPS645438Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small speaker system that can obtain characteristics similar to those of a large speaker system.

Closed speaker systems that use only the sound waves emitted from the front of the speaker have a sealed cabinet that acts like a spring on the speaker, making it difficult for the diaphragm to move. The resonance frequency o increases, making it difficult to produce bass sounds. This tendency becomes more pronounced as the internal volume of the cabinet becomes smaller.

Conventionally, when it is not possible to increase the internal volume of the cabinet, the mass of the vibration system such as the speaker's diaphragm is increased to suppress the increase in the bass resonance frequency. The disadvantage is that it becomes very bad. Separately, the inside of the cabinet has been filled with sound absorbing material such as glass wool to reduce the stiffness of the box, but this method was not sufficient to suppress the rise in bass resonance frequency.

The purpose of this invention is to solve the above-mentioned problem by absorbing the sound pressure behind the speaker that emits sound waves by another speaker, so that even a small speaker system can have the same effect as a large speaker system. The goal is to make it possible to obtain specific characteristics.

The internal pressure of a small closed speaker system is
When the diaphragm moves forward, the pressure becomes less than atmospheric pressure, providing resistance to the forward displacement of the diaphragm, and when the diaphragm displaces backwards (in the direction of the back), the pressure becomes greater than atmospheric pressure, providing resistance to backward displacement. give. This phenomenon becomes noticeable during bass reproduction when the displacement of the diaphragm is large.

Therefore, in the present invention, a baffle plate with a speaker attached is installed inside the cabinet of a closed speaker system, dividing the inside of the cabinet into two, and vibrating the speaker for sound wave emission and the internal speaker in almost the same phase. so that the back pressure of the speaker for sound wave emission does not change.

Examples of the present invention will be described below. 1st
The figure shows one embodiment of the system. Reference numeral 1 indicates a sealed cabinet, in which a first speaker 2 for emitting sound waves is attached to the sound emitting port 1a on the front side, and a buffer plate 3 is installed inside. A second speaker 4 for absorbing internal pressure is attached to the sound emitting port 3a of the baffle plate 3. The first and second speakers 2 and 4 are bass speakers with the same characteristics, and the sound emitting surface of the second speaker 4 faces the back side of the first speaker, and the second speaker 4 and the second speaker 4 are connected to each other. Cabinet 1 by plate 3
The interior is divided into two rooms, A and B, in a sealed state. 5 and 6 are sound absorbing materials filled in chambers A and B, and 7 is an amplifier.

When both speakers 2 and 4 are driven by applying the audio signal applied to the input terminal 8 in the same phase so that both speakers 2 and 4 are driven in the same phase, the diaphragm of the first speaker 2 When the diaphragm of the second speaker 4 is displaced forward, the diaphragm of the second speaker 4 is also displaced forward, and when the diaphragm of the first speaker 2 is displaced rearward, the diaphragm of the second speaker 4 is also displaced rearward. do.

Therefore, the pressure change in the chamber A due to the driving of the first speaker 2 is absorbed by the vibration of the second speaker 4 and reduced, and the diaphragm of the first speaker 2 has an almost infinite sealed space at the back. It vibrates with a large volume, and the bass resonance frequency of the first speaker 2 can be lowered.

In order for the diaphragm of the first speaker 2 to vibrate freely, more precisely, the pressure immediately behind the back surface of the diaphragm becomes a problem. In this respect, in the above embodiment, the pressure change caused by the second speaker 4 immediately behind the rear surface of the diaphragm of the first speaker 2 is delayed by the distance between the two speakers 2 and 4.

FIG. 2 takes into account this delay, and a delay circuit 9 is interposed in the audio signal path of the first speaker 2, so that the audio signal applied to the second speaker 4 is transferred to the first speaker 2. It is designed to be faster than the audio signal applied to the In this case, the delay time of the delay circuit 9 is made to correspond to the sound pressure propagation time between the first and second speakers 2 and 4, so that the pressure on the back of the diaphragm of the first speaker 2 is always the same. It can be operated in this state.

Note that this sound pressure propagation time changes depending on the temperature, so if the delay time of the delay circuit 9 is compensated by a temperature sensing element installed in the room A, a delay time that corresponds to the temperature can be obtained. .

From the above, according to the present invention, it is possible to sufficiently satisfy the bass reproduction characteristics of small speaker systems, which have had problems in the past, and it is also possible to increase the output as well, thereby making it possible to improve the performance of large speaker systems. The feature is that it is possible to realize a small speaker system similar to that of the above.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a speaker system according to one embodiment of the present invention, and FIG. 2 is a sectional view showing another embodiment of the speaker system including a delay circuit. DESCRIPTION OF SYMBOLS 1... Sealed cabinet, 2... First speaker, 3... Bumpy board, 4... Second speaker, 5, 6... Sound absorbing material, 7... Amplifier, 8... Input terminal, 9 ...Delay circuit.

Claims (1)

[Claims for Utility Model Registration] (1) A first speaker is attached to the sound emitting port of the closed cabinet, and a buttful plate is attached inside the cabinet so as to divide the cabinet into two, and the first speaker is attached to the buttful plate. A second speaker, which is the same as the first speaker, is mounted so that its sound emitting surface faces the back of the first speaker, and the first and second speakers are driven in substantially the same phase. speaker system. (2) The speaker system according to claim 1, wherein the same audio signal is applied to the first and second speakers.