A Large Radius Stylus for the Reproduction of Lateral Cut Phonograph Records

Abstract

This paper shows that novel and unexpected benefits are obtained by use of a stylus of sufficiently large tip radius to contact only the upper portions of the side walls of a laterally cut phonograph record groove. The benefits are: (a) an increase in high frequency output; (b) a decrease in acoustic radiation from the surface of the record; (c) an increase in record life; (d) an increase in stylus life; (e) a decrease in picked up scratch frown both new and worn records; (f) a decrease in stylus point pressure required for proper tracking. A stylus tip which will give this performance for the case of standard commercial records has a radius on the order of 4.2 mils or nearly double the radius of 2.3 mils heretofore thought most desirable. This device is in commercial use in conjunction with the Crosley radio-phonograph combinations and is the subject of U. S. patent 2,251,204. In commercial use the large radius stylus is combined with a special spring mounting and drives a crystal cartridge. The spring mounted stylus was developed in conjunction with Mr. Frank Goldsmith and the additional benefits obtained thereby are explained in the preceding paper. (The presentation of this paper will be accompanied by demonstrations of the benefits obtained with the large radius stylus utilizing both sound reproduction and oscillographic illustration.)