Abstract: 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.

Abstract: 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.

Abstract: A vehicular speaker system in which a resonance of the vehicle's interior is compensated by a resonance of a chamber enclosing the rear of the speaker unit. The chamber includes rearwardly facing ports.

Abstract: A headrest-mounted acoustic device including at least a speaker mounted on the right or left side of a headrest provided on a seat, a cover mounted in the sound radiating direction of the speaker, and a sound radiating portion communicating with a chamber provided behind the cover and having an area much smaller than that which is defined by the diameter of the speaker, so that sounds from the speaker are radiated from the sound radiating part through the chamber.

Abstract: A car speaker system which can be used to radiate sound either inside the vehicle in normal driving use or outside the vehicle when the vehicle is parked. A plurality of speaker units are mounted in a closed cabinet and the cabinet is swingably mounted along one side thereof in a casing. In a first swinging position of the cabinet, the speaker mounting surface of the cabinet is flush with the ceiling panel and the speakers radiate sound downwards into the passenger compartment of the vehicle, while in a second swinging position of the cabinet, the speaker mounting surface is perpendicular to the ceiling panel and the speakers face rearwards to radiate sound to the exterior through an open hatchback door.