Pioneer Electronic Corporation

Masahiko Ito

Kazunori Takagi

Shinichi Sato

Hideo Yamamoto

An audio reproduction system for use in an audio amplifier, for example, has a tone control unit for increasing or reducing a gain, or keeping an increased or reduced gain, of a signal if a particular frequency range of an audio signal supplied thereto, and a volume control unit for increasing or reducing the gain of the audio signal in a full effective frequency range. The tone and volume control units are ganged by a gain control unit, so that the gain which has been increased in the particular frequency by the tone control unit, can be controlled depending on the degree to which the gain has been increased by the volume control unit. The tone and volume control units may include variable resistors, respectively, whose movable contacts are interconnected. When the knob of the volume control unit is shifted toward a higher scale level position, the gain of the signal in the particular frequency range is lowered by the tone control unit, thereby preventing the reproduced sound from being distorted. When the knob of the volume control unit is shifted toward a lower scale level position, the gain of the signal in the particular frequency range is increased by the tone control unit.

Audio reproduction system

A mobile stereo speaker unit and assembly includes a central speaker for reproducing both left and right stereo sound channels. The central speaker is in a well in the central portion of the front panel of a vehicle, and a reflector is positioned above the speaker to intercept the sound and reflect it in a desired direction. The direction is selectable vertically or horizontally depending on the particular reflector used and the reflected sound may be directed towards the rear or towards the front windshield.

Mobile stereo speaker set

In an automatic loudness compensator provided in a sound reproduction device in a vehicle, the sound level is compensated to reproduce a sound source with the high fidelity intended by the producer of the source of sound. The level of sound frequency-pressure is increased or decreased relative to a middle range of sound frequency at a sound level lower or higher than a reference sound level, respectively. The level of sound frequency-pressure is also adjusted based on the noise produced by the movement of the vehicle and on the acoustic characteristic of the passenger compartment of the vehicle.

Automatic sound level compensator for a sound reproduction device

In an adjustable power fader device for a loudspeaker system with at least four speakers right and left channel input signals are received by respective power fader circuits. Each power fader circuit has a variable resistor connected across its input terminals and a series of at least two speakers across its output terminals. The sliding terminal of the variable resistor is connected via a capacitor to the mid point of the series of speakers, one of which has good low pitch sound reproduction. The two sliding terminals of the respective power fader circuits are movable together and the level of audio signals applied to the loudspeakers is accordingly adjusted.

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Kawagoe, Japan

Masahiko Ito