- Anne Beetem Acker
Disc, usually of metal, plastic, or glass, on which are inscribed or drawn waveforms, or a cylinder or disc with a toothed or profiled rim. Originally used for producing an audio frequency for radio receivers, the wheel or cylinder rotates as part of an electromechanical system, producing regular fluctuations in the current corresponding to the frequency represented by the waveform or profile. The fluctuations are amplified and heard through a loudspeaker. Hammond organ tonewheels are about 5 cm in diameter. The frequency produced depends upon the rotation speed, as well as the waveform or profile. While tonewheels are generally designed to produce a pure sine wave, ‘harmonic leakage’ from adjacent tonewheels can produce harmonics that can be considered either objectionable or part of the timbre....