 While the Hammond organ was originally sold to churches as a lower-cost alternative to the pipe organ, it came to be used for jazz, blues, and then to a greater extent in rock music (in the 1960s and 1970s) and gospel music.The original Hammond organ imitated the function of a pipe organ's ranks of pipes in multiple registers by using additive synthesis of waveforms from harmonic series to generate its sounds.The Hammond organ's individual waveforms were made by mechanical tonewheels which rotated beneath electromagnetic pickups.