MT 17 Sound calibrators

Sound calibrators are small portable devices designed to produce one or more known sound pressure levels at one or more specified frequencies when coupled to specified models of microphone in specified configurations. The sound pressure level generated by some sound calibrators depends on the static pressure. Their principle use is in checking or adjusting the overall sensitivity of acoustical measuring devices or systems, including in the field, but they can also be used to determine the electroacoustical pressure sensitivity of specified models of microphone in specified configurations.

MT17 covers the specification for sound calibrators and also standardised test methods for the pattern evaluation of different models of sound calibrator and for the periodic testing of individual specimens of sound calibrator.

When a sound calibrator is used with a sound level meter various different corrections may need to applied and MT17 is also responsible for the IEC standard on the determination of these corrections.

MT17 does not cover other functions a sound calibrator can provide, for example, tonebursts.

Standardisation is necessary for a range of reasons:

•to ensure consistency in performance of sound calibrators and in measurement of the produced outputs, such as sound pressure level and frequency

•to ensure consistency of testing and testing methodologies throughout the world

•when a sound calibrator is used to adjust a measuring device such as a sound level meter this in turn leads to consistency of measurement using that device

•enables measurements to be made that are traceable to national or international measurement standards

•enables the user to be confident that their instrument is operating as intended and in accordance with the specifications given in the appropriate international specification standard.

Convenor

Daniela Toledo Helboe, Norway

helboe@norsonic.com