AES Announces New AES75 Standard for Loudspeaker Measurement

[beeface]

AES Announces New AES75 Standard for Loudspeaker Measurement - AES

The Audio Engineering Society has announced the adoption and publication of AES75-2022

aes2.org

 

[sweetchaos]

This is HUGE news!
We're going to have another standard that we can rely on.

To understand the problem, watch this 3-min clip:

The idea is to use the "M-Noise" for measuring loudspeaker Maximum Linear SPL.
Without doing this, the task of measuring max SPL was very difficult (or impossible?), since every manufacturer had their own way of measuring and displaying the max SPL.
Instead, we now have a standard for this process.

Full report (need to be an AES member):

AES Standard » AES75-2023: AES standard for acoustics — Measuring loudspeaker maximum linear sound levels using noise

This standard details a procedure for measuring maximum linear sound levels of a loudspeaker system or driver using a test signal called Music-Noise. In order to measure maximum linear sound levels meaningfully and repeatably, a signal is required whose RMS and peak levels as functions of...

www.aes.org

Here's the preview of the report:

https://www.aes.org/tmpFiles/aessc/20220323/aes75-2022-i.pdf

Here's the "AES Melbourne February 2022 Meeting - Merlijn Van Veen" (1.5hr video, from 2022):

Slides for this presentation:

https://www.aesmelbourne.org.au/wp-content/media/AES-Feb2022.pdf

Here's the "SMPTE 2019: A New Signal for Measuring Loudspeaker Maximum Linear SPL" (30min video from 2019):

This is very exciting!

Would love to hear thoughts from our experts.

cc @amirm @hardisj

 

[Sancus]

My question is:

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.

(I don't have AES access) How are those last two things measured? The first sounds like a compression test, the other is ?? -- I didn't have time to watch videos so maybe this question is answered in there.

 

[amirm]

If it is just m-noise then it is not if much interest.

 

[Soniclife]

If it is just m-noise then it is not if much interest.

Can you explain why please, it sounds like a good idea to this layman.

 

[anotherhobby]

Can you explain why please, it sounds like a good idea to this layman.

To this layman, I just think this is far more useful to the professional audio market, like live music, PA systems, and big venue type stuff. I just wouldn't call it HUGE news, at least not in the context of home audio.

 

[amirm]

To this layman, I just think this is far more useful to the professional audio market, like live music, PA systems, and big venue type stuff. I just wouldn't call it HUGE news, at least not in the context of home audio.

That's basically it. It is just burst rather than continuous noise for testing. This allows less powerful speakers to get higher SPL numbers they can advertise. High SPL numbers are major metric for PA and hence their interest in this.

One could argue that music is also dynamic so this kind of testing is closer there but we rarely worry about peak SPL rating determined in simplistic manners for home hifi use.

 

[Jon AA]

Put me down as one happy to see it. I'm not 100% sold, I'd like to see data (listening tests) to show they drew the line for distortion at a reasonable level as it relates to audibility. But if they got it even close to right, IMHO it's 1000 times better than what we have now in the consumer space--which is nothing.

Many who like to badmouth CTA-2034/Preference scores, etc, often pick out a tiny monitor that scores "better than the JBL M2! That's absurd! Obviously, CTA-2034 is useless!"

Of course we all (should) know, that's not the case at all. CTA-2034 simply isn't measuring the things that make the speakers so different. If there was an AES75 dB rating to go along with the Spin, it would be obvious one shouldn't be comparing the spins of those two speakers at all, as you would never be choosing between the two for the same application.

Some really good speakers which are of a smaller physical size may get a surprisingly high AES75 dB rating, which would show they may be considered for applications where people were considering speakers of much larger physical size.

It also may help explain why some speakers do better in subjective testing than the Spin suggests it should (JBL 4349, etc). Dynamics matter, and any standard that does a reasonable job of measuring that potential for a speaker is welcome news to me.