Ultrasonic Cleaners Wreck ANC

uller6

macrumors 6502
Original poster
May 14, 2010
304
200
I work in a relatively loud research lab, so I wear my airpods pro without music on a lot of the time just for the noise cancelling. It’s fantastic.

Yesterday I was cleaning some metal parts in the ultrasonic cleaner, and my airpods pro kept flipping out. If I turned my head towards the ultrasonic cleaner, the AirPod closest to the cleaner would stop the ANC. If I spun my head around the other way then the AirPod facing the ultrasonic cleaner would stop ANC, while the AirPod now facing away from the cleaner would start the ANC again. It was really disorienting and threw me off balance.

I think the microphones on the outside of the airpods pickup the ultrasonic signal, but then since the speakers can’t reproduce frequencies that high the ANC goes haywire.

Hey Apple, any chance you could put a low pass filter on the external microphone to prevent this happening?
 

Ralfi

macrumors 68040
Dec 22, 2016
3,406
2,194
Australia
This is the first I’ve heard of ANC turning off. What I’ve found is the opposite, where if high pitched sounds come on (building alarms, timer chime of kitchen appliances), then either the bud nearest to the sound, or both buds will switch on ANC (presumedly to protect the ears), before switching back to Transparency mode after the sound ends.

Not sure why ANC turns off in your case. Or I should say I’m not sure why anyone would want it to turn off. It should just be auto-enabled to protect your ears, as I mentioned above.
 

bwinter88

macrumors regular
Jul 20, 2012
136
248
I’ve noticed when I pass by loud constant sounds like motors running or construction humming the ANC initially performs well, but then after a half-second, gets worse. Like it’s trying to adapt, but adapts the wrong way. It’s very bizarre, and annoying, because it works great for the first moment, so i know it’s purely a software issue.

Just try using the ANC around your coffee grinder and you’ll see what I mean.
 

V_Man

macrumors 6502a
Aug 1, 2013
624
1,031
This is the first I’ve heard of ANC turning off. What I’ve found is the opposite, where if high pitched sounds come on (building alarms, timer chime of kitchen appliances), then either the bud nearest to the sound, or both buds will switch on ANC (presumedly to protect the ears), before switching back to Transparency mode after the sound ends.

Not sure why ANC turns off in your case. Or I should say I’m not sure why anyone would want it to turn off. It should just be auto-enabled to protect your ears, as I mentioned above.
This is the Apple way of doing things. Those times when you go this is why I live Apple
 

uller6

macrumors 6502
Original poster
May 14, 2010
304
200
Not sure why ANC turns off in your case. Or I should say I’m not sure why anyone would want it to turn off. It should just be auto-enabled to protect your ears, as I mentioned above.
I think it’s related to the high frequencies of ultrasound and how the ANC software handles them.

My situation is a pretty rare edge case and likely was not anticipated by Apple engineers.
 
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RogerWilco6502

macrumors 65816
Jan 12, 2019
1,187
1,083
I think it’s related to the high frequencies of ultrasound and how the ANC software handles them.

My situation is a pretty rare edge case and likely was not anticipated by Apple engineers.
I think you're on to something. Presumably the ANC in the AirPods Pro works by trying to produce noise at a frequency that cancels out the frequency of the noise that it is picking up. It is reasonable to expect that the algorithm can't account for ultrasound assuming this is how it works.
 
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Furfural

macrumors newbie
Sep 24, 2018
3
5
Noticed the same last week. The ultrasonic baths in our lab were making funny ANC glitches but a probe sonicator was not.
 
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