Abstracts of Technical Papers from Bell System Sources (01 July 1937)

Jour. S. M. P. E., March 1937. Etec. Engg., April 1937. 420 ABSTRACTS OF TECHNICAL ARTICLES 421 Direct Recording and Reproducing Materials for Disk Recording.3 A . C. KELLER. Recently materials for direct recording and reproducing work have been improved so t h a t they are now suitable for many uses. 

These materials, as they are available on the market, are classified chemically into five groups and measurements are given of frequency characteristic, surface noise, life, distortion, etc. These data have been taken with both lateral and vertical recording. 3 Jour. Acous. Soc. Amer., April 1937.