JPH0215720Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an in-vehicle sound generating device such as a radio receiver or a cassette tape recorder that is installed in the interior of an automobile.

In a sound generating system in which two or more speakers, which are sound generating elements, are placed in the front and rear of a car interior, if there are people only in the front seats, the rear speakers are placed in order to balance the sound from the front and rear speakers. I am listening with the speakers operating at the maximum front/rear balance adjustment position. However, if there are people in the rear seats, if the rear speakers are operated at the maximum setting, the rear seats will feel noisy and will not be able to listen to music comfortably.

The purpose of this invention is to solve the above-mentioned technical problems,
To provide an in-vehicle sound generating device that allows a person in a rear seat to comfortably listen to music.

The present invention includes a first signal path in which sound generating elements are arranged at the front and rear of the interior of a car, and a first signal path that supplies an audio information signal to the front sound generating element via a first attenuator; and a second signal path for supplying the audio information signal to a rear sound generating element via a second attenuator, the audio information signal being supplied to the second signal path. A vehicle-mounted sound generating device is provided with a switching means for supplying the sound to the second attenuation means with or without a low-pass filter.

FIG. 1 is a simplified top view showing the interior A of an automobile. At the front B of the room A, a front speaker 8, which is a sound generating element, is installed.
A rear speaker 9, which is a sound generating element, is installed on a tray C in the room A. The people sitting in the front seat D and the rear seat E will hear the sound from the front speaker 8 and the rear speaker 9 installed in this way.

FIG. 2 is a block diagram of one embodiment of the present invention. The output of the audio amplification circuit 1 is connected to an attenuator 4 and a common contact c of the changeover switch 2. Attenuator 4
The output of is connected to the power amplifier circuit 6. The output of the power amplifier circuit 6 is connected to a front speaker 8 which is a sound generating element. Contact a of changeover switch 2
is connected to the attenuator 5. A contact b of the changeover switch 2 is connected to a low-pass filter circuit 3.
The output of the low pass filter circuit 3 is connected to an attenuator 5. The output of the attenuator 5 is connected to a power amplifier circuit 7. The output of the power amplifier circuit 7 is connected to a rear speaker 9 which is a sound generating element.

Here, as shown in FIG.
Assume that a common contact c is connected to a contact a. The audio signal in the audible frequency range sent out from the audio amplification circuit 1 is applied to the attenuator 4 and the common contact c of the changeover switch 2. The attenuator 4 attenuates the audio signal over the entire range and supplies it to the power amplifier circuit 6. The power amplification circuit 6 amplifies the power of the received audio signal and supplies it to the front speaker 8 . The front speaker 8 converts the power-amplified audio signal into sound and emits the sound to the outside. The attenuator 5 receives the audio signal via the common contact c and the contact a of the changeover switch 2, and attenuates the entire range of the audio signal. The audio signal attenuated by the attenuator 5 is given to the power amplifier circuit 7. The power amplified audio signal derived from the power amplification circuit 7 is given to the rear speaker 9. The rear speaker 9 converts the power-amplified audio signal into sound and emits the sound to the outside. The volume from the front speaker 8 is adjusted by an attenuator 4, and the volume from the rear speaker 9 is adjusted by an attenuator 5.

As described above, when the common contact c of the changeover switch 2 is connected to the contact a, and a person who is only in the front seat of the car listens to music, the volume of the front speakers 8 and rear speakers 9 will change. For balance, the attenuators 4 and 5 are adjusted so that the sound coming from the rear speakers 9 is louder than the sound coming from the front speakers 8. However, if there are people only in the front seats in the car, the sound from the rear speakers 9 may be loud, but if there are people in the rear seats, the sound from the rear speakers 9 will be louder for the people in the rear seats. It feels so loud that I can't listen to music comfortably.

Therefore, it is necessary to enable people in the rear seats to listen to music comfortably. To achieve this, common contact c of changeover switch 2 is switched to contact b. The case where the common contact c of the changeover switch 2 is connected to the contact b will be described below.
The audio signal derived from the audio amplification circuit 1 is applied to an attenuator 4 and a common contact c of the changeover switch 2. The audio signal attenuated by the attenuator 4 is provided to a power amplifier circuit 6. The power amplification circuit 6 amplifies the power of the received audio signal and supplies it to the front speaker 8 . The sound from the front speaker 8 has frequencies in the entire audible frequency range.

On the other hand, the audio signal applied to the common contact c of the changeover switch 2 is applied to the low-pass filter circuit 3 via the contact b. In the low-pass filter circuit 3, the cutoff frequency is set in advance to, for example, 80Hz. Therefore, the low pass filter circuit 3
The output of the attenuator 5 sends out an audio signal of less than 80Hz.
give that audio signal to. The audio signal attenuated below 80 Hz by the attenuator 5 is provided to the power amplifier circuit 7. The audio signal that is the output from the power amplifier circuit 7 is given to the rear speaker 9.
It is made into sound. Since the sound generated from the rear speaker 9 has a frequency of around 80 Hz, only the bass is emphasized. Therefore, even if the volume of the rear speakers is made higher than the volume of the front speakers, those in the rear seats can hear the bass to their ears and hear the treble from the front speakers 8, so they can listen to music comfortably. Can be done. Also, people in the front seats can listen to music with a well-balanced sound field.

In this embodiment, the cutoff frequency of the low-pass filter circuit 3 is set to 80 Hz, but it may be set to another value. Also, as shown in Figure 1, one front speaker 8 is installed on the front B, and one rear speaker 9 is installed on the tray C.
However, the number of these speakers is not limited to one each, and a plurality of speakers may be installed.

As described above, according to the present invention, it is possible to switch so that only the low sound is generated from the rear sound generating element among the sound generating elements arranged at the front and rear of the vehicle interior, so that only the low sound is generated from the rear sound generating element. Alternatively, music or the like can be reproduced with a well-balanced sound field even when there are people in the front and rear seats.

[Brief explanation of the drawing]

FIG. 1 is a simplified top view showing the interior of an automobile, and FIG. 2 is a block diagram of an embodiment of the present invention. 1... Audio amplification circuit, 2... Selector switch, 3
...Low pass filter circuit, 4,5...Attenuator,
6, 7...Power amplifier circuit, 8...Front speaker,
9...Rear speaker.

Claims (1)

[Claims for Utility Model Registration] A first signal path in which sound generating elements are arranged at the front and rear of the interior of an automobile, and which supplies an audio information signal to the front sound generating element via a first attenuator; and a second signal path for supplying an audio information signal to a rear sound generating element via a second attenuator, the second signal path including the A vehicle-mounted sound generating device, characterized in that a switching means is provided for supplying the audio information signal to the second attenuation means with or without a low-pass filter.