Pioneer Electronic Corporation

Pioneer Corporation

Shinjiro Kato

Fumio Tamura

Hisashi Kihara

Toshikazu Yoshimi

Shuichi Mori

Takeshi Sato

Akio Tokumo

Yoshiro Kunugi

Yoshio Sasaki

Makoto Odaka

Masayuki Kato

Hideo Yamamoto

Takami Maeda

Kazuhito Tatsuta

Masayaki Kato

Shuuichi Mori

In an audio apparatusto which plural kinds of audio signals of different numbers of channels are input, a sound field control sectionwhich performs a sound field control on the audio signals on the basis of a sound field control data is provided, and the sound field control data is stored in a memoryfor each of the kinds of audio signals.

Audio apparatus

A tone control apparatus for a sound system processing audio signals of front and rear channels. By providing front and rear tone control means for independently effecting the tone control in both of the front and rear channels, it is possible to prevent the generation of distortions in the front acoustic output when the control for raising the rear bass level is effected. Also, a tone control balance between the front and rear channels in a vehicle cabin, for example, can be set appropriately.

Tone control apparatus for front and rear channels

Disclosed herein is a digital audio signal processing apparatus of a type wherein a graphic equalizer including a plurality of filters connected in series to one another is subjected to arithmetic operation processing to be defined to thereby output the result of its processing as data therefrom. When a change-over command is generated, one filter out of the plurality of filters except for filters positioned at both ends is supplied to one of two output terminals with output data of a filter immediately before said one filter, the stored data is applied to the input of a filter immediately after said one filter and output data of a final filter is applied to the other of said two output terminals so as to define two graphic equalizers. Thus, where it is desired to carry out a change in the mode from arithmetic operation processing which defines a graphic equalizer comprising a plurality of bands to arithmetic operation processing which defines two-separated graphic equalizers comprising a plurality of bands or to the contrary, where it is desired to carry out a change in the mode contrary to the mode referred to above, the change in the arithmetic operation processing can be completed in a relatively short time.

Digital audio signal processing apparatus

AN on-board vehicle automatic sound volume adjusting apparatus which adjusts the level of an input audio signal in accordance with the difference between the input audio signal level and the running noise level inside the vehicle and which compresses the input audio signal in terms of amplitude according to the level difference. The apparatus inhibits the masking of the minimum component in the reproduced sound volume, and prevents the maximum component therein from becoming excessive when the running noise level is raised.

On-board vehicle automatic sound volume adjusting apparatus

A sound field correcting device provides for a natural acoustic localization of the outputs of right and left channels of an acoustic sound source. At least one of right and left channel audio signals is delayed to create a phase difference between the right and left channel audio signals, and to thus dislocate a sound in such a way that a listener not positioned equidistant between right and left channel sound sources may perceive the two channels equally.

Device for correcting a sound field in a narrow space

An automatic sound volume controller for use with audio equipment mounted on a vehicle adapted that the level of an input audio signal and that of the noises coming inside the cabin in running state are detected, and the difference therebetween is obtained. By use of different gain levels reflecting the level difference, a direct sound signal and an effect sound signal are individually amplified for synthesis. This makes it possible to prevent the added effect sounds from being masked by the running noises because the level of the effect sound signal varies with the noises. As a result, the reproduced sounds supplemented by the effect sounds can be heard clearly while the vehicle is running. With the vehicle in stationary state, the effect sounds are kept from getting excessive, protecting the vehicle passengers from the unpleasant sensation conventionally associated with the apparatus of this kind.

Automatic sound volume controller

An on-vehicle automatic loudness control apparatus according to the present invention comprises a volume control circuit for receiving an audio signal from an audio signal source, the volume control circuit controlling an output level therefrom in accordance with a first signal supplied thereto; a level detecting unit for receiving the output level from volume control circuit, the level detector controlling an output level therefrom in accordance with a second signal supplied thereto, a noise detecting unit for detecting environmental noise in a passenger space of a car to output a noise signal in accordance with the environmental noise level; a relative level detecting circuit for comparing the output level from the level detector with the noise signal to output a third signal indicative of a relative magnitude between the output level from the level detector and the noise signal; and a control circuit for outputting the first signal and the second signal in accordance with the third signal. The second signal causes the output level from level detector to decrease when the output level of the volume control circuit is increased, and the second signal causes the output from level detector to increase when the output level from volume control circuit is decreased.

On-vehicle automatic loudness control apparatus

A sound field correcting system for correcting for mulitpath frequency-characteristic distortion in an acoustic reproducing system. In one embodiment, the level and delay of an original signal are adjusted and superposed on the original signal so as to obtain a signal which, when reproduced by a loudspeaker, yields a sound pattern at a listening point having a flat frequency characteristic. The delay adjustment is effected in accordance with a difference between the travel distances of direct and reflected sound waves to the listening point.

Sound field correction system

A speaker system for a vehicle having both front and rear speakers. Both speakers are connected in parallel to an amplifier. The impedance of the rear speaker circuit is made greater than that of the front speaker circuit. A resistor may be placed in series with the rear speaker or a shorting ring may be attached to the coil of the front speaker to decrease the high frequency impedance.

Balanced vehicular speaker system

A sound field correcting system for correcting for multipath frequency-characteristic distortion in an acoustic reproducing system. In one embodiment, the level and delay of an original signal are adjusted and superposed on the original signal so as to obtain a signal which, when reproduced by a loudspeaker, yields a sound pattern at a listening point having a flat frequency characteristic. The delay adjustment is effected in accordance with a difference between the travel distances of direct and reflected sound waves to the listening point.

An automatic volume control apparatus for use in a mobile audio apparatus in which a detection output from a noise detection section is compared with a control output applied to a volume control section, and a capacitor inserted between a control signal input terminal of the volume control section and a reference voltage point is charged/discharged by a current source section with a constant current on the basis of the output of the comparator to thereby make it possible to make the change of volume constant or linear relative to the change of noise level. Also, a control signal for a volume controller is obtained by subtracting a quantity of logarithmic change of an audio signal detection signal obtained from an audio signal detection section relative to a reference value from a value obtained by amplifying, with an amplification factor in a range of 1.5 to 2.5, a quantity of logarithmic change of a noise detection signal obtained from a noise detection section relative to a reference value, whereby the correspondence between levels of low-frequency components of, for example, 10 Hz or less and audible frequency components of in-vehicle noise becomes higher so that it is possible to perform more natural volume control.

Mobile automatic volume control apparatus

A sound field correcting device for use in a stereophonic system intended for vehicular use. Speakers are installed on opposite sides of both the front and rear seats of the vehicle. The number of persons seated in the vehicle is determined and applied to a correcting unit. When plural persons are seated in the vehicle, the sound pressure levels in the high-frequency range of loudspeakers is increased. Also, the sound pressure levels of the speakers can be corrected in accordance with the positions at which persons are seated in the vehicle.

Mobile sound field correcting device

A mobile sound field correcting system for correcting an acoustic characteristic in a vehicle sound field formed by direct waves radiated from loudspeakers and reflected waves thereof providing satisfactory acoustic characteristics for different vehicles and different listening points within a vehicle. A first correcting means corrects a power spectrum of each loudspeaker in a frequency range above a frequency at which a decrease of starts of the power spectrum in a high-frequency range of each loudspeaker. Second correcting means corrects for irregularities in the frequency characteristic of each loudspeaker caused by interference of the direct waves with the reflected waves in a frequency lower than the drop-off frequency of this power spectrum.

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Saitama, Japan

Shinjiro Kato