Sidney got his start in the record business following the end of World War II, as a distributor of Jewish folk records.
Beginning in the 1950's Sidney began producing high fidelity records, with an emphasis on sound (and sound effects).
He was also the creator of the first commercial stereo records (through his Audio Fidelity Records label in New York).
In 1957, Sidney had used Westrex, a stereo disk-cutting system, to cut a stereo LP disk for release before any of the major record labels, several of which had the Westrex equipment but had not yet produced a stereo disk.
This demonstration disc was introduced to the public on December 13, 1957 at the Times Auditorium in New York City
500 copies of this initial demonstration record were pressed.
On December 16, 1957, Frey advertised in the trade magazine Billboard that he would send a free copy to anyone in the industry who wrote to him on company letterhead.
That move generated a great deal of publicity and launched a revolution in the way the world listens to music: on two channels, for two ears, in stereo. Frey promptly released four additional stereo disks. The equipment dealers had no choice but to demonstrate on Audio Fidelity Records. Frey became known as "Mr. Stereo" during that era.
Sidney Frey sold the Audio Fidelity company/label to Herman D. Gimbel April 1964
He died of a heart attack on January 13, 1968, at the age of 47.