Testing Apple’s latest noise-cancelling earbuds at 39,000 feet reveals a potential flaw most users won’t notice, until they fly.
basicappleguy.com
To save a click, I'll just c+p the main part:
My trouble came at 39,000 feet when I first noticed a high-pitched whine coming from my left AirPod. The issue was that the AirPod’s ear seal kept loosening, leading to a noise-cancellation feedback loop and a painfully loud piercing screech from the AirPod. Attempts to readjust worsened the feedback, especially if I accidentally covered the external microphone with my finger. This happened multiple times, making the experience so unpleasant that I eventually switched to my spare EarPods for the remainder of the flight. While disappointed, I wasn’t ready to condemn the headphones yet; perhaps the medium seal worked fine on terra firma, but on flights, I might need a different size for a better seal.
After landing, I tested the tips and switched from a Medium to Extra Small (Apple offers XXS, XS, S, M, or L tips for AirPods Pro 3). Both XS and M tips sealed well and were comfortable for long wear. For weeks, I couldn’t reproduce the whistling feedback, and I forgot about it until my next flight earlier this week.
Once again, it was only a few minutes after takeoff that the painful screech returned. Careful adjustments or yawning would fix the issue, but only for a couple of minutes at most. I figured that the new foam tips were trapping more heat, reducing airflow and ventilation, and less flexible, and that somehow all that was playing a role in loosening the seal. And when paired with the aircraft’s loud, steady hum, a feedback loop was created. But day to day, this is a non-issue because I never encounter the same types of pressure changes and noises that would reproduce this issue.
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Really concerning issue that seems to impact some people when up in the sky... I'm perfectly fine with my APP2's (lightning model no less, I mostly just use them for travel) and Airpods 4 with ANC for everything but if I were tempted, this would be something I'd have to be certain I wouldn't experience cause it sounds like a total deal breaker, changes to the fit aside (that I would also have to try out, since its a ymmv thing depending on your ear shape and size).