an instrument for the measurement of hearing acuity and, specifically, for the threshold of audibility
sonometer - an instrument designed to respond to sound in approximately the same way the human ear does and to give objective and reproducible measurements of sound pressure levels. Many systems for measuring sound are available. Although different in their details, each system has a microphone, a measuring section, and a reading unit.
The quantities defined in Article 2 can be either: (i) measured directly by integrating sonometers, or (ii) calculated from measurements of sound pressure and exposure duration.
