Justin_copyright

RIAA notes RIAA stands for recording industry association of america. it was a group that devoloped standards for recordings for this country. the RIAA went back to the195. the standards are below.

A. Introduction

A true stereophonic disc record has two distinct orthogonal modulations derived from an original live recording in which a minimum of two separate channels are employed.

B. The Stereophonic Groove

1. The stereophonic groove shall contain two channels of information recorded as orthogonal modulations of a single groove. 2. The 45 degree-45 degree system is the standard. In this system the two mutually perpendicular axes of modulation shall be symmetrically disposed with respect to a normal to the disc surface. 3. The right hand information channel, as viewed by the listener, shall appear as modulation of the out side wall of the groove. 4. When equal in-phase signals are recorded in the two channels they shall result in lateral modulation of the stereophonic groove shall produce equal in-phase acoustical signals. 5. The stereophonic groove contour shall be as recommended in RIAA Dimensional Standards for Disc Phonograph Records, Bulletin E 4.

C. Characteristic

1. For stereophonic disc records the RIAA Standard Recording and Reproducing characteristic shall be standard. D. Reproduction Recommendations 1. The desirable tip radius of the reproducing stylus for stereophonic disc records is 0.5 mils. 2. The reproducing stylus motion shall be tangent to, or lie in a plane which passes through the record center, and which is inclined at a nominal angle of 15 degrees, clockwise, to a normal to the record at the stylus tip, as viewed from the record c enter.