AES announces AES75 standard for maximum SPL rating

The Audio Engineering Society has announced the adoption and publication of AES75-2022, “AES standard for acoustics - Measuring loudspeaker maximum linear sound levels using noise.” The new standard addresses the need for a practical and cohesive procedure for the measurement of maximum SPL and is the result of extensive work by the AES Standards Committee’s SC-04-03-A Task Group, co-chaired by Merlijn van Veen and Roger Schwenke.

Evaluation of loudspeaker performance based on published specifications has traditionally been challenging due to inconsistencies in both measurement procedures and in how measured parameters are reported. “Until now,” explains Schwenke, “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,” Schwenke 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.”

The 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 test signal reaches an unacceptable state. The AES75 test procedures cover performance measurements of both self-powered and externally powered loudspeakers.

Credit for the development of AES75 is owed to the large task group, AES’s standards management and to Meyer Sound’s original work, shares van Veen. “The chairs would like to acknowledge the nearly 80 task group members who represent all market verticals such as, but not limited to, automotive, consumer electronics, pro audio, post-production, and cinema,” he says. “For more than two years — during a pandemic — we met more than 50 times, every other week, which is extraordinary given the circumstances! Special recognition goes to the AES, Bruce Olson, Richard Cabot [AES standards manager], and Steve Hutt [recent co-chair AES Technical Council].”