JPS5846631Y2 - Speaker connection circuit - Google Patents

Description

[Detailed description of the invention] This invention relates to a connection circuit between the built-in speaker of an audio device and an external speaker connected to this device.The purpose of this invention is to To provide a speaker connection circuit that uses a built-in speaker and an external speaker in combination to further improve the reproduction characteristics of a speaker system when an external speaker is connected to a device for listening.

Traditionally, portable cassette tape recorders with radio receivers are limited by the size and performance of the built-in speakers, so when using them in a stationary position, it is possible to switch to a large external speaker using an external output jack. It is being said.

Furthermore, with stereo cassette tape recorders, there is a problem in that the installation spacing between the left and right built-in speakers is also restricted by the device dimensions, so in order to obtain a sufficient stereo effect, two external speakers must be installed at the desired spacing. Sometimes the tape recorder is played back.

However, in conventional cassette tape recorders, etc., the built-in speaker and external speaker are simply switched and used alternatively, and there is no consideration for using both together and sharing different playback frequencies with each speaker. It had not been done.

The idea behind this idea is that external speakers typically have large diameters mounted on large baffle boards, which have good bass reproduction efficiency, whereas built-in speakers are mainly of medium diameter or smaller. Focusing on the good reproduction efficiency in the mid-high range, we decided to use both speakers together to improve the reproduction characteristics of the speaker system. Figure 1 shows a speaker connection circuit that is an example of this.

1 is a power amplifier, 2 is an external output jack, 3 is a built-in speaker, and 4 is a built-in treble speaker (hereinafter referred to as a tweeter). A low-cut capacitor C1 is connected between C and C, and when an external speaker (not shown) is connected, the output of the power amplifier 1 is connected directly to the built-in speaker 3 because C is closed. Furthermore, the signal is applied to the tweeter 4 through a low-cut capacitor C2.

The output sound pressure level of each speaker in this case is as shown in FIG.

Next, when an external speaker is connected, the output of the power amplifier 1 is applied to it through the external output jack 2, but when a speaker plug (not shown) is inserted and contacts are made, C opens. The output of the power amplifier 1 is applied to the built-in speaker 3 through a low-cut capacitor C1, and further to the tweeter 4 through a low-cut capacitor C2.

In this case, the mid-high range of the signal applied to the external speaker is bypassed by the series circuit of the capacitor C1 and the built-in speaker 3, and the low-frequency range of the signal applied to the built-in speaker 3 is bypassed by the low-cut capacitor C1, and the low-frequency range is bypassed by the low-cut capacitor C2. The high frequency range is also bypassed by the series circuit of the tweeter 4 and the tweeter 4, and a signal with the middle and low frequency frequencies cut is applied to the tweeter 4 through the low cut capacitors C1 and C2.

Therefore, the output sound pressure level of each speaker in this case is as shown in FIG. 3, and the reproduction frequency band is shifted and narrower than in the case of FIG. 2.

In other words, in this invention, when no external speaker is connected, the built-in speaker covers almost all reproduction frequencies, but when an external speaker is connected, both the external and built-in speakers share this frequency. Switching between the above two cases is achieved by a simple configuration of an external output jack and a capacitor.

As described above, by using an external speaker and a built-in speaker together, this invention narrows the reproduction frequency of each, allowing each speaker to be used in a frequency band with good reproduction efficiency, increasing the acoustic output, and It has the advantage of increasing the permissible input of the speaker system relative to the power amplifier output, and since it only requires an output jack and a capacitor to be added to the conventional circuit, it can be realized with a simple configuration, and there is only a slight increase in cost. It has the advantage of being easy to use.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an example of the speaker connection circuit of this invention, Figure 2 is an output sound pressure level characteristic diagram of only the built-in speaker, and Figure 3 is the output sound when the built-in speaker and external speaker are used together. It is a pressure level characteristic diagram. 1...Power amplifier, 2...External output jack, 3...Built-in speaker, 4...
・Tweeter, C1, C2...Low cut capacitor.

Claims (1)

[Scope of utility model registration request] In audio equipment equipped with a built-in speaker, a power amplifier, and an external output jack for supplying the output of the power amplifier to an external speaker, a switch for the external output jack that is normally closed and opens when a connection plug is inserted. Connect a low frequency capacitor between the contacts, and if an external speaker is not connected, the output of the power amplifier will be applied to the built-in speaker through the short circuit between the low frequency capacitor and the capacitor, but if an external speaker is connected. In this case, the power amplifier output bypassed by the series circuit of the above-mentioned capacitor and built-in speaker is applied to the external speaker, and the power amplifier output is applied to the built-in speaker through this capacitor, and the external speaker mainly receives low frequency signals. A speaker connection circuit that intercepts the output of the built-in speaker in such a way that it loads mainly the output of medium and high frequencies.