Meyer Sound has applauded the adoption and publication of a new standard for loudspeaker measurement, AES75-2022. The ‘AES Standard for Acoustics: Measuring loudspeaker maximum linear sound levels using noise’ includes the M-Noise test signal and an independently verifiable test procedure.
The company said that the new standard marks a long-awaited breakthrough in the analysis and objective comparison of loudspeaker output levels.
“Having a common and clearly defined test procedure coupled with a test signal that reflects real-world applications is of enormous benefit to audio professionals,” said John Meyer, president and CEO of Meyer Sound. “It not only allows users to verify the performance limits of their current systems, but also lets them make meaningful, apples-to-apples comparisons of published data for different loudspeakers.”
In the work of the AES SC-04-03-A Task Group, AES75 details a procedure for measuring maximum linear sound levels of a loudspeaker system or individual driver using the M-Noise test signal. Mathematically derived from analysis of hundreds of music selections spanning all genres, M-Noise is designed to exhibit a crest factor characteristic of music programme signals. The specified test procedure determines maximum linear sound levels by incrementally increasing playback levels until reaching a stop condition: an unacceptable change in the transfer function’s magnitude or coherence. Specific procedural steps are outlined to accommodate both self-powered and externally powered loudspeakers.
“AES75 is designed to be independently verifiable using analysers and measurement microphones typically used by audio professionals,” said Meyer Sound senior scientist and innovation steward Roger Schwenke, Ph.D., a co-chair of the task group. “Because it is independently verifiable, AES75 provides audio system specifiers and users a much more enforceable metric to use in project tenders and architectural specifications.”
Nearly 80 task group members contributed to the development and review of the AES75 standard, with representatives from automotive and consumer electronics, cinema and post-production as well as pro audio.
“I feel that the industry at large has spoken through this new standard, signalling that the time has finally come to have a level playing field in terms of SPL performance metrics,” said Merlijn van Veen, task group co-chair and senior technical support and education specialist at Meyer Sound. “AES75 ushers in a new era, one that should be welcomed by end users and loudspeaker manufacturers alike.”
Introduced 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 analysers.
“We are grateful for the many substantive contributions made by the committee, particularly regarding procedures for externally powered loudspeakers,” said Schwenke. “And we are also very aware of the trust placed in Meyer Sound by adopting the original M-Noise test signal into the standard with no changes.”