An audio apparatus includes a touch detective muting arrangement. Switch actuating knobs made of metal are electrically insulated from the circuit ground and connected to an electro-static field detector circuit detecting a touch of an operator's finger with the knobs and producing a control signal. A muting circuit is provided in the audio signal path and connected to the detector circuit to be controlled by the control signal. When a finger touches the knob, the muting circuit is rendered operative to mute the audio signal, thus preventing undesirable click noise which might otherwise come out in accordance with changing-over manipulation of the switch.
A voice recording/playback apparatus includes a head unit which records a voice signal in a recording medium and for playing back a recorded voice signal from the recording medium. A playback head amplifier unit amplifies a playback signal output from the head unit. A voice output unit outputs a voice in accordance with the playback signal amplified by the playback head amplifier unit. A muting switch is provided between the playback head amplifier unit and the voice output unit. The muting switch cuts off a connection between the playback head amplifier unit and the voice output unit when a voice recording mode is performed by the head unit.
A tuning device for a radio receiver comprises a manual tuning system to manually drive a variable capacitor and an automatic tuning system to drive the same by a motor, wherein the mechanism for transmitting a motive force of a manipulated tuning knob to the variable capacitor in the manual tuning mode is arranged in a mechanically independent relation with a motive force transmitting mechanism provided by a motor in the automatic tuning mode, and the selection of either one of the two transmitting mechanisms is effected by a clutch mechanism whose connection of either one of the two transmitting mechanisms to the variable capacitor is changed over by a touch switch electrically connected to the tuning knob of the receiver.
An automatic electronic control system for a home entertainment center, the system utilizing audio signal sensors for the preferential selection of the record player or the tape deck as a signal source but with provision for returning to the tuner upon the cessation of the signal from either of the preferred sources. A manual mode is also provided which utilizes proximity switches.
Improved audio reproduction apparatus permits upgrading a two channel high fidelity ("stereo") system to four channel ("quadraphonic") capability, while flexibly accommodating varying four channel source signal formats, e.g., four channel discrete, or encoded two channel SQ (e.g., tape, FM) or CD-4 (phonograph). The composite arrangement includes demodulation circuitry for the variously formated incoming signals, and plural variable gain amplifier arrays for final signal source selection which is readily effected by off-board minimal, DC switching.
Dual program audio apparatus is provided having two or more sources of input audio program signals, switching circuitry for selecting two of the input audio signals for amplification, one or more amplifiers for amplifying the selected input audio program signals, and one or more audio speakers for enabling a listener to hear both audio programs simultaneously. Volume control circuitry is provided for selecting a higher volume level for a foreground program and a relatively lower volume for a background program and circuitry is provided for selectively interchanging the foreground and background programs either instantaneously or gradually and continuously.
