The AES75 standard, published in 2022, details a procedure for measuring maximum linear sound levels of a loudspeaker system or driver using a test signal called M-Noise, recognizing a development effort initiated in 2019. M-Noise was developed as a means for determining the maximum linear output levels of loudspeaker systems when used in music reinforcement applications. To assure consistent repeatability, a test procedure was developed that specified test parameters and described requirements for associated microphones, signal generators and analyzers. The authors research was detailed in this Loudspeaker Industry Sourcebook article.
So far, audioXpress has received notice that support for measurements according to AES75 standard has been integrated in the latest Listen SoundCheck v20 software, and as one of the options provided by CODA Audio in its System Optimiser v0.6 software. There are certainly more products supporting the standard and publishing an comprehensive list would certainly provide useful guidance.
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. 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.
According to Richard Cabot, Standards Manager for the Audio Engineering Society, the AES SC-04-03-A task group is currently in the process of publicizing the standard and establishing a number of assets. One of these will be a webpage — dedicated to AES75 — under the AES website.
In support of its efforts, the SC-04-03-A task group now made request to all organizations that have previously expressed interest in using AES75 to specify maximum linear sound levels of their own products, to support AES75-compliant measurements in test and measurement solutions, or offering AES75-compliant measurement services. The appeal is for these companies and professionals to reach out to the SC-04-03-A task group confirming their ongoing interest in the standard and, if possible, provide an update on their progress.
Replies should be submitted to the AES Standards email.
Those responding positively, will be contacted further with an opportunity to be included on the AES75 webpage listing organizations showing active support. A detailed response or any suggestions will receive the full attention of the task group.
These ongoing expressions of interest should be submitted by March 15th, 2023.
www.aes.org
