Hammond serial number dating
The drawbars, which operate like the faders on an audio mixing board, allow the performer to vary the volume of each notes' fundamental tone, the octave below it, and the octaves and harmonics above it.Other features added to Hammond organs included an electromechanical vibrato and, by the late 1950s, a reverb effect which simulated the reverberation of a large church hall.The drawbars add harmonics to the original note that each key produces.
The component waveforms can be mixed in varying ratios by using 'drawbars' mounted above the two keyboards.
In imitation of a pipe organ, with its banks of pipes in multiple registers, the Hammond Organ used additive synthesis of waveforms from harmonic series to generate its sounds.
As in Thaddeus Cahill's earlier Telharmonium, the individual waveforms were made by mechanical 'tonewheels' which rotated beneath electromagnetic pickups.
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The Hammond organ is an electric organ which was designed and built by Laurens Hammond in April 1935.