JPS60230800A - On-vehicle speaker system - Google Patents

Abstract

PURPOSE:To obtain a rich low frequency reproduction always without damaging a low-frequency by providing a means for transmitting only a low frequency of an audio signal and supplying a pair of speakers excellent in a low frequency reproduction characteristic through a variable resistance. CONSTITUTION:Audio signals are inputted to terminals Lin and Rin. A cut-off frequency of an LPF16 passes frequency below low frequency sounds of 100- 150Hz less of an upward directional feeling in terms of acoustic sense, while HPFs 2 and 6 passes the frequency band which will not be passed by the LPF16. For instance, when sliding pieces 1', 5', 9' and 12' are slid in the direction as shown in C, in variable resistances 1 and 5, reproduction sounds from front speakers 4 and 8 become smaller, because audio signals from right and left speakers 4 and 8 are attenuated, and reproduction sounds covering an entire band from rear speakers 11 and 14 are emphasized. When the sliding pieces are slid in the D direction, high frequency is reproduced from the speakers 4 and 8, whereas outputs from the speakers 11 and 14 will not be reproduced.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a vehicle-mounted speaker system equipped with a volume balance control circuit for controlling the audio signal level supplied to a plurality of front and rear speakers installed in a vehicle interior.

Conventional technology and problems In car speaker systems, there is a four-speaker system in which two front speakers are placed on both sides of the front instrument panel or on the left and right doors, and two rear speakers are placed on both sides of the rear sun deck. This is commonly used, and such speaker systems generally include a volume balance control circuit (hereinafter referred to as a control circuit) that can adjust the volume balance between the front speakers and the rear speakers.

FIG. 3 is a block diagram showing a conventional control circuit, in which left channel and right channel audio signals are input from a tuner, cassette deck, etc. (not shown) to input terminals Lin and Rin. The left channel signal is input to both input ends of the variable resistor 21 via resistors R, R. The output of the variable resistor 21 is the power amplifier 23.27
The signal is inputted to the front left speaker 24 and the rear left speaker 28 via the front left speaker 24 and drives both speakers. The right channel signal is inputted to both input ends of the variable resistor '22 via resistors R and R, and further inputted to the front right speaker 26 and the rear right speaker 30 via the power amplifier 25.29, and is inputted to each speaker. drive The variable resistors 21 and 22 are configured in an interlocked manner, and a control circuit is configured by these two variable resistors.

Adjust the volume balance between the front and rear speakers using variable resistor 21.2.
2 sliding terminals 21' and 22'. For example, if the sliding terminals 21" and 22" are slid toward the side not indicated by arrow A in the figure, the output of the rear speakers 28.30 is emphasized and the output of the front speakers 24.26 is attenuated.B in the figure If you slide it to the side indicated by , the opposite will occur.

By the way, many cars have a relatively large rear deck space, so they use a relatively large diameter (for example, 16 to 20 cm).
) speaker unit can be installed, and the trunk room can be used as a hack cavity for the speaker, so it is very advantageous for reproducing low frequencies as shown in Figure 2 (al), and can reproduce even a considerable low frequency range. However, due to space constraints, front speakers can only be installed with speaker units with a small diameter (about 1Qcm at most), and the panfuru effect is often insufficient. cannot be fully reproduced.

Under these conditions, conventional control circuits change the volume balance between speaker systems with different low-frequency reproduction characteristics as described above, which changes not only the sound field balance but also the frequency balance of the reproduced sound. . In particular, when the control circuit was tilted toward the front speakers, which have poor bass reproduction characteristics (attenuating the rear speaker output), the reproduced sound was significantly lacking in bass.

Purpose of the Invention The present invention has been made in view of the above-mentioned conventional drawbacks, and includes:
The purpose is to provide a system that eliminates changes in low-frequency reproduced sound due to the position of the sliding terminal of the volume balance control circuit.

According to the present invention, the present invention includes a volume balance control circuit that controls the level of an audio signal using a variable resistor, and a plurality of speaker pairs having different low frequency reproduction characteristics connected to the output of the variable resistor. An in-vehicle speaker system is provided with means for passing only the low frequency range of the audio signal, and the output of the means is configured to be supplied via the variable resistor to a pair of speakers having excellent low frequency reproduction characteristics. This is accomplished by a speaker system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. Audio signals from audio equipment such as a tuner and a cassette deck (not shown) are input to input terminals Lin and R4n. Lin is the input terminal for the left channel signal, R
ln is an input terminal for the right channel signal. Input terminal l
The left channel signal input to in is connected to variable resistors 1 and 9.
The signal is input to one input terminal of , and is also input to the mixing circuit 15 . The output of the variable resistor 1 is inputted from the sliding terminal 1'' to the front left speaker 4 via the bypass filter 2 and the power amplifier 3 to drive the speaker 4.The variable resistor 9
The output is transmitted from the sliding terminal 9' to the rear left speaker 11 via the power amplifier 10 and drives the speaker 11. Further, the right channel signal input to the input terminal Rin is input to one input terminal of the variable resistors 5 and 12, and is also input to the mixing circuit 15. The output of the variable resistor 5 is input from the sliding terminal 5' to the front right speaker 8 via the bypass filter 6 and the power amplifier 7 to drive the speaker 8. The output of the variable resistor 12 is manually applied from the sliding terminal 12' to the rear right speaker 14 via the power amplifier 13 to drive the speaker 14. The mixing circuit 15 mixes the left and right channel signals, and the output signal is sent to a low-pass filter 16 and a buffer circuit 17 for adjusting impedance.
It is inputted to the other input terminals of variable resistors 9 and 12 via.

Here, the cutoff frequency of the low-pass filter 16 is configured to pass a low frequency range with little auditory sense of direction, that is, a low frequency range of 100 to 150 Hz or less. The bypass filter 2.6 is configured to pass the frequency band that is not passed by the low-pass filter 16.゛The variable resistors 1 and 5.9.12 are of an interlocking type, and a control circuit is constituted by these variable resistors. Furthermore, the front speaker pair 4.8 has poor low frequency reproduction characteristics as shown in Figure 2 (b), and the rear speaker pair 8.14 has excellent low frequency reproduction characteristics as shown in Figure 2 (il). It is something that

The operation of this embodiment will be explained below.

The output levels of variable resistor pair 1.5 and variable resistor pair 9.12 are inversely proportional to each other. In other words, the ty dynamic terminal l゛, 5
When the variable resistors 1, 9, and 12' are located at the midpoints of the variable resistors 1, 5, 9, and 12 (as shown), each speaker 4.8
．． From 11.14 onwards, the output will be played back at the same volume. At this time, mainly high-frequency sounds are output and reproduced from the front speaker 4.8 by the bypass filter 2.6, and the rear speaker 11.1
From 4 onwards, the entire area will be output and reproduced. When the sliding terminals 1゛, 5°, 9°, and 12゛ are slid in the direction shown by C in the figure, the audio signals of the left and right channels are attenuated in the variable resistor 1.5, so the front speakers 4.8
The volume output from rear speaker 1 becomes smaller.
The output reproduction sound over the entire band from 1.14 is emphasized.

At this time, the output signal of the buffer circuit 17 is transferred to the variable resistor 9.
12, and the output is not reproduced from the speakers 11 and 14. Therefore, when the sliding terminals 1°, 5°, 9°, and 12° are fully compressed in the direction of arrow C, the sound reproduced from the front speakers 4.8 disappears, and only the sound reproduced over the entire band from the rear speakers 11 and 4. Output.

Next, when sliding terminals 1", 5", 9", and 12" are moved by tV in the direction shown by the arrow, high-frequency sound is output and reproduced from the front speaker 4.8, while the variable resistor 9.12 The left channel signal and right channel signal respectively input to one input terminal are attenuated by the resistor and output to the rear speakers 11 and 14.
There is no output playback from. However, the low-frequency signal that is the output of the buffer circuit F, that is, the low-frequency signal with little sense of direction that has been cut off by the bypass filter 2.
．． The signal is output and reproduced from rear speakers 11.14 via the other end of 12, sliding terminals 9'' and 12'', and power amplifier 10113. Therefore, if the sliding terminals 1°, 5", 9", and 12" are squeezed in the direction of the arrow, the front speaker will be 4.8".
From the rear speakers 11.14, only the high-frequency range defined by the bypass filter 2.6 is output, and from the rear speakers 11.14, only the low-frequency range defined by the low-pass filter 16 is output. As in the case where each slider is fully squeezed, the entire range is output, and the frequency balance is no longer disrupted. At this time, since the low range output from the rear speakers 11.14 has no sense of direction, the listener will not be able to feel that it is being output from the rear speakers 11.14, and the function of the control circuit will not be impaired. do not have. Incidentally, in the above embodiment, the left and right channel signals are mixed and output and reproduced, but even if the signal is a stereo signal, there is little audible sense of direction in the low frequency range of 100 to 15 oz or less, so mixing is performed. Even if you play back later, the stereo feeling will not be affected. In that case, a stereo feeling can be obtained by separating the mid- and high-frequency ranges.

Also, although it is not necessary to provide bypass filters 2 and 6, it is possible to avoid the difference in low-frequency reproduction characteristics by having them output only from speakers with poor low-frequency reproduction characteristics. Interference in the low frequency range can be prevented, and since low frequency signals that would cause small speakers with poor low frequency reproduction characteristics to produce unreasonably large amplitudes are not input, cross modulation distortion in the speaker system can be prevented. You can.Furthermore,
Since the bandwidth of the power amplifier system that drives the small speaker system is limited, cross-modulation distortion can be prevented and a wide range can be obtained.

The effects of the invention will now be explained in detail.According to the present invention, when the volume balance control circuit is adjusted to the speaker side with poor low-frequency reproduction characteristics, the low-frequency range with less sense of direction is changed from the speaker side with excellent low-frequency reproduction characteristics. Since the left and right channels are mixed and output, rich bass reproduction can always be obtained without sacrificing the bass range.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the in-vehicle speaker system of the present invention, Fig. 2 is a frequency characteristic diagram of the speaker, and Fig. 3 is a diagram showing the frequency characteristics of the speaker.
The figure is a block diagram showing a conventional in-vehicle speaker system. In the figure, 1, 5, 9.12 are variable resistors, 2.6 is a noise pass filter, and 3. 7. 10.13 is a power amplifier,
4, 8. IL 14 is a speaker, 15 is a mixing circuit,
16 is a low-pass filter, and 17 is a buffer circuit. Patent applicant Fujitsu Ten Ltd. 1st share 1) 15 1/

Claims (1)

[Claims] In a car speaker system that includes a volume balance control circuit that controls the level of an audio signal using a variable resistor, and a plurality of speaker pairs with different low frequency reproduction characteristics connected to the output of the variable resistor, 1. A vehicle-mounted speaker system, characterized in that a means for passing only the frequency range is provided, and the output of the means is configured to be supplied via the variable resistor to a pair of speakers having excellent low-frequency reproduction characteristics.