Reproducing Styli for Speech Audiometry

Abstract

Between 1956 and 1958, Technisonic Studios changed the groove shape on the lateral-cut monophonic recordings that they supply for speech audiometry. A stylus that has a spherical tip with a radius of 1/1000 inch (1.0 mil) is the most appropriate one for reproducing (playing) Technisonic discs pressed since 1959. The tone arms on many speech audiometers, however, still are equipped with a larger (2.5 mil) stylus. This report presents a rationale for using the 1.0-mil stylus. Methods are suggested for identification of groove shape on the Technisonic discs and for identification of stylus size.