A recent firmware update to AirPods Pro was was meant to improve the audio quality overall, but seems to have reduced the ability to block some ambient noise at lower frequencies.
Apple released the affected firmware update on December 16, 2019, which may have reduced audio isolation performance. Audio review site Rtings performed a new round of tests to evaluate the AirPods Pro ANC while running the 2C54 update, and found that user complaints were accurate.
"After updating to Firmware [2C54], we retested the headphones and our results showed a fairly significant drop in isolation performance, primarily in the bass-range," discovered Rtings. "This means that with ANC turned on, these headphones won't do nearly as good a job blocking out the low engine rumbles of planes or buses as they did before this update. This review reflects these changes."
The reduction in isolation has been directly attributed in Apple's attempt to increase audio quality, and more specifically bass accuracy. Rtings also reflected this change saying that the result "showed a fairly significant improvement to bass accuracy."
The 2C54 update was pulled shortly after release for reasons not entirely clear, but users were already complaining about a difference in the active noise cancellation system (ANC). Also unclear, is how many users ultimately were affected by this update.
Apple's AirPods Pro are the high end version of Apple's truly wireless earphones. Released in September 2019, they debuted as an upgrade path from the existing second generation AirPods, rather than acting as a replacement. AirPods Pro offered Active Noise Cancelling and changeable ear tips for a premium $250 price tag. Check out AppleInsider's Price Guide for more purchasing information and deals.