HARMONISER

The simplest methods are used to increase pitch and reduce note durations, or vice versa, reduce pitch and increase note duration. This can be done by replaying a sound waveform at a different speed than it was recorded. It could be accomplished on an early reel-to-reel tape recorder by changing the diameter of the capstan drive shaft, or using a different motor. As technologies improved later designs of motor speeds could be controlled by electronic servo system circuits. This arrangement using “vari-speed” capstan motors allowed the speed change to be achieved more simply