Varitone

It was marketed in 1967 by the Selmer Company, which developed units for flute, saxophone, and clarinet.

The system included an integrated pickup microphone and a control box which allowed the player to use effects such as tremolo, basic EQ ("bright" and "dark"), simultaneous sub-octaves and echo in conjunction with a purpose-built amplifier.

[1] Similar products included the Hammond Condor, the Conn Multi-vider and the Maestro series of analogue effects boxes marketed by Chicago Musical Instruments.

Notable Varitone players were Eddie Harris,[2] Lou Donaldson, Moe Koffman, and Sonny Stitt.

Varitone is also the name of a device used for changing the sounds of an electric guitar, featured on Gibson's BB King "Lucille" signature ES-355.