EV Stereo-4 (1970 – 1975)

The EV Stereo-4 system (also known as EV-4) was a matrix quadraphonic format, developed by Leonard Feldman and Jon Fixler in 1970 and taken up by Electro-Voice as the first commercial quadraphonic system for vinyl records.

A handful of record labels used the system, including Ovation, Project 3 and Quad-Spectrum, and RadioShack sold compatible decoders and systems in the US.

EV Stereo-4 emphasises front (left to right) and front-to-rear separation, but there is less separation between the two rear channels.

In 1973 Electro-Voice introduced a decoder that could also play SQ and QS quadraphonic records with good results, but despite this Stereo-4 was pushed out of the market by these other systems and nothing appears to have been released on EV Stereo-4 after 1975.

Sources / Resources