本规程规定了一种U型音频测试胶片，用于调整35 mm电影磁工作室音频复制机的灵敏度和频率响应，该复制机以每秒96个穿孔或大约每分钟90英尺（27米）的速度运行，用于单声道、三声道、四声道和六声道音频系统。

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.