AES Standards News Blog

AES75-2022, "AES  standard for acoustics – Measuring loudspeaker maximum linear sound levels using noise" has been published on 2022-03-04.

This standard details a procedure for measuring maximum linear sound levels of a loudspeaker system or driver using a test signal called M-Noise. In order to measure maximum linear sound levels meaningfully and repeatably, a signal is required whose RMS and peak levels as functions of frequency have been shown to be representative of program material. Various existing standards define noise-based test signals which, like M-Noise, have incorporated the knowledge that typical program material has a diminishing RMS level with increasing frequency, but M-Noise uniquely also features a relatively constant peak level as a function of frequency, so that the crest factor (peak level – RMS level) increases with frequency, which an analysis on a large variety of music and other content has revealed is an important additional characteristic of typical program material. The specified procedure determines a loudspeaker’s maximum linear sound levels by incrementally increasing the Playback Level of M-Noise until a stop condition is met: either an unacceptable change in the transfer function’s magnitude or an unacceptable change in the coherence of the transfer function.

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