They are best known for having produced the first mass-produced American stereophonic long-playing record in November 1957 (although this was not available to the general public until March of the following year).

However, 43 North Broadway had apparently been reproducing and distributing the Audio Fidelity recordings without a license, and using counterfeit trademarks to deceive the public according to the lawsuit.

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.

[14] In the summer of 1958, Audio Fidelity recorded 13 classical LPs in London's Walthamstow Town Hall.

[12] Six of the LPs were conducted by Alfred Wallenstein, who concentrated on the symphonic repertoire (including Brahms's 4th Symphony, Tchaikovsky's Pathetique, and Berlioz's Symphonie Fantastique) and six by Arthur Winograd (both conductors were ex-cellists) who recorded lighter fare, such as operatic marches and popular overtures.

[12] Collector Don W. Reichle compiled a comprehensive database and collection of Audio Fidelity recordings which are now housed at the Syracuse University Library.