AES Announces New AES75 Standard for Loudspeaker Measurement

Specific test procedures cover self-powered and externally powered units

The Audio Engineering Society has adopted and published AES75-2022. The “AES standard for acoustics — Measuring loudspeaker maximum linear sound levels using noise” addresses the need for a practical and cohesive procedure for prediction of loudspeaker performance.

AES75 is the result of extensive work by the AES Standards Committee’s SC-04-03-A Task Group, co-chaired by Merlijn van Veen, senior technical support and education specialist, Meyer Sound, and Roger Schwenke Ph.D., senior scientist and innovation steward, Meyer Sound.

“The work of the drafting group was deliberate and thoughtful as they carefully refined the standard,” says AES Standards Chair Bruce Olson. “AES75 will no doubt join the most impactful standards that the society has published in its long history of providing the audio industry with critical tools for analyzing the performance of audio equipment and ensuring interoperability.”

Meyer Sound’s Roger Schwenke (left) and Merlijn van Veen chaired the AES Task Group that developed AES75-2022.

Predictive evaluation of loudspeaker performance based on published specifications has traditionally been challenging because of inconsistencies both in measurement procedures and in how measured parameters are reported. “Until now,” Schwenke explains, “reading an SPL number on a datasheet often inspired more questions than answers regarding test signals used and procedures for measurement. Most important to the end user is how the loudspeaker will perform with typical audio signals and whether the numbers can be compared apples-to-apples with numbers from one datasheet to another.

“AES75 addresses these issues,” he continues, “by providing a detailed procedure as well as a specific test signal, M-Noise, whose RMS and peak levels as functions of frequency have been shown to better represent typical program material. Furthermore, AES75 is designed to be independently verifiable, using analyzers and microphones typically used by audio professionals. By being independently verifiable, AES75 provides system specifiers and users a much more enforceable metric to use in quotes and architectural specs.”

The M-Noise test-signal procedures documented in AES75 provide measurement of maximum linear sound levels by incrementally increasing playback levels until the magnitude or coherence of a loudspeaker’s acoustic reproduction of the M-Noise test signal reaches an unacceptable state. The AES75 test procedures cover performance measurements of both self-powered and externally powered loudspeakers.

More information about AES75-2022 can be found in the Audio Engineering Society’s Standards News Blog. The AES75 standard, the M-Noise signals, and coherence test tracks are available for download at aes.org.

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