A New Standard Volume Indicator and Reference Level*

Abstract

In recent years it has become increasingly difficult to correlate readings of volume level made by various groups because of differences in the characteristics and calibrations of the volume indicators used. This paper describes a joint development by the Columbia Broadcasting System, National Broadcasting Company, and Bell Telephone Laboratories which resulted in agreement upon, and standardization in the respective broadcast and Bell System plants, of: a new copper-oxide rectifier type of volume indicator having prescribed dynamic and electrical characteristics; a new reference level based on the calibration of the new instrument with a single frequency power of one milliwatt; and a new terminology, the readings being described in “vu.” It if hoped that other users of volume indicators will join in the adoption of these new standards.