Matsushita Electric Industrial Co., Ltd.

Akitoshi Yamada

Yoichi Kimura

Yoshinobu Kikuchi

Ryoji Suzuki

Kiyotaka Nagai

Toshiyuki Goto

An echo canceller includes means for reducing correlation in a receiving side input signal based on a linear prediction model by regarding the receiving side input signal as an output signal of the linear prediction model. This means for reducing correlation is provided in a form suitable for hardware implementation, and thus, a convergence rate for the receiving side input signal having strong correlation as a speech signal can be improved without substantially increasing the number of calculations or the amount of memory.

Echo canceller

A sound reproduction system for a motor vehicle in which two channel signals are applied to two loudspeakers provided in the passenger compartment to reproduce the signals. The system includes a transfer function converting circuit for converting transfer functions between a listener and the first and second speakers into different transfer functions in different directions from those to the first and second speakers, a delay circuit for compensating for a distant difference between the listener and the first and second speakers, and a reverberation circuit for providing reverberation to two channel input signals, whereby a feeling of a widened sound region is obtained even in a small passenger compartment.

Sound reproduction system for motor vehicle

A headphone device comprising a pair of headphones for receiving output signals from various acoustic apparatus, wherein a direct sound signal or an output signal of an acoustic apparatus is applied to a reverberation supply circuit to produce an indirect sound signal, said indirect sound signal being mixed with said direct sound signal with a ratio of more than 1 : 10 to control the feeling of distance to a sound image existing outside the head, and further the direct sound signal is added to another channel through an attenuator to control the feeling of the direction of the sound image, whereby a natural listening condition similar to the case of loudspeaker listening is obtained.

Out-of-head localization headphone listening device

The present invention relates to a headphone apparatus which is adapted to be connected, for headphone listening, to a reproduction apparatus for reproducing a program source such as a record, a magnetic tape or an acoustic apparatus such as a radio receiving set. In accordance with the present invention, there is provided a headphone apparatus in which a direct audio frequency signal as an output signal from the electroacoustic apparatus is applied to reverberation circuits to generate indirect audio frequency signals and these direct and indirect audio frequency signals are mixed and applied to both the left and right electroacoustic transducers of the headphone apparatus, whereby an acoustic image can be established outside the listener's head just as in the case of listening to speakers.

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Daito, Japan

Akitoshi Yamada