RCA Mark II

The RCA MKII synthesiser at the Colombia-Princeton Eectronic Music Centre 1956

The RCA Synthesiser was invented by the electronic engineers Harry Olsen and Hebert Belar, employed at RCA’s Princeton Laboratories, as a way of electronically generating popular music. Although it never fulfilled its inventors expectations it’s novel features were an inspiration for a number of electronic composers during the 1950’s.


Harry F Olson in 1956 The publication of “A Mathematical Theory Of Music” (1949) inspired Belar and Olsen to create a machine to generate music based on a system of random probability. The theory being that random variations of already created popular songs could be used to create new marketeable songs.This flawed theory never came to fruition partly due to the lack of sufficient processing power available at the time and partly to the mistaken concept that the basis of composition could be gleaned from mathematical analysis of a muscial piece.

The sound source was again the Vacuum Tube Oscillator (12 of them in the mkI and 24 in the mkII) but with a unique progammable sound contoller in the form of a punch-paper roll which allowed the composer to predefine a complex set of sound parameters. This allowed the mixing of generated sounds and shaping the sound with dividers, filters, envelope filters, modulators and resonators.

The final audio was monitored on two speakers and recorded to an internal laquer disk cutter, giving six concentric grooves-a total of 3 minutes per groove – which could then in turn be mixed together onto another laquer disk (this archaic system was not updated to the more flexible tape recorder until 1959). By re using and bouncing the disk recordings a totall of 216 sound track could be used

Sound File
A Laquer disc recording fgrom the RCA Synthesiser.

In 1957 a grant from the Rockefeller Foundation, Columbia University was able to rent the RCA Syntheiser MkII and set up the Columbia-Princeton Electronic Music Centre. This organisation became one of the most important centres of elctronic music during the 1950s. New electronic Composers such as Otto Luening, Vladimir Ussachevsky , Milton Babbit and others were now able to experiment with programming complex serial-type compositions on the MKII RCA, which previously were too tricky for a composer to handle manually.

The punch-paper keyboard input of the RCA MKII

A diagram of the RCA MkII showing hard disk recording and paper roll programmer.