SMPTE RP 127 – Specifications for Type U Audio Level and Multifrequency Test Film for 35-mm Studio Audio Reproducers, Magnetic Full-Coat Type
This practice specifies a type U audio frequency test film to be used for adjusting the sensitivity and frequency response of 35-mm motion-picture magnetic studio audio reproducers operating at 96 perforations per second or approximately 90 ft (27 m) per minute for use with one-, three-, four-, and six-track audio systems.
