Are Audyssey mics basically the same?

[krabapple]

I've managed to accumulate five Audyssey mics for various Denons that have passed through my setups over the years. I used to keep them in chronological order, but managed to mix them all up recently. The only thing that differentiates them visibly is a factory-numbered label on the bottom and, in one case, a different colored plastic surround on the bottom (black instead of the usual brown) .

Does any of this matter? Are they interchangeable for use in Denon calibration? Do they 'go bad' with age and if so, does the label number tell me anything?

 

[No. 5]

Good questions! Just like pricy pre-polarized capsules, inexpensive electric mic capsules can most definitely loose sensitivity over time, and frequency response can change too, but I wouldn't expect more than a few dB of change unless something has gone extremely wrong. If there is a few Decibel change, I wouldn't be surprised if it's still within or close to Denon's tolerances from their supplier, since a decent inexpensive small capsule like that should be basically flat below ~2kHz, and given the mic's themselves not having a serial number Denon/Audyssey is betting on unit to unit consistency rather than "real" calibration.

 

[Zedly]

Several years ago, someone posted measurements of several Audyssey mics. They were all basically the same under 5KHz, though some required level matching.

https://www.avsforum.com/threads/comparing-3-audyssey-acm1hb-microphones.2678793/

 

[Zedly]

There is also a video where someone compares the standard Audyssey mic with the ACM1-X individually calibrated mic. The audio is in Portuguese, but using auto-translated captions works well enough to understand (measurements begin at 7:15).