Since iPadOS 27, the 3.5 mm headphone output on iPad (9th generation) is 2.4 to 4.5 dB quieter than on iPadOS 26, depending on frequency, with the same content, system volume and headphones. It's still present in iPadOS 27.2 beta 2 (24B5089g).
It isn't app-specific. It reproduces in Safari:
- Connect wired headphones to the 3.5 mm jack and set system volume to 100%.
- Open https://www.szynalski.com/tone-generator/, set 3000 Hz, set the generator volume to 50%, and play.
- Measure with a sound level meter. At 3 kHz we see 2.5 to 2.9 dB less on iPadOS 27 than on iPadOS 26, across three different headphone models.
Audio settings are identical between the two OS versions and Bluetooth is off. The only session-level difference we found is AVAudioSession.outputLatency, which went from 97 to 65 frames.
Filed as FB24980117.