I have a 2023 M2 Max Macbook pro 14 inch attached to an Apple Studio Display. People tell me my voice sounds normal on video calls made from this machine, and I've checked that, a Signal video call to a phone sounds perfect on the phone. And music played through the Studio Display sounds great. But when I try to record my voice using the Apple Voice Memos app, or Quicktime doing a screen recording, or Audacity, choosing either the Studio Display mic or the Macbook's own mic, the treble disappears. If I record in Audacity and then boost the treble by about 12 dB, it sounds sort-of-ok again. It's as though some digital filtering in the macbook is applied to the audio signal before feeding it to the app. But only to the recorder apps, not to Chrome running Google Chat, or Signal, or Whatsapp.
What might be going on?
I tried connecting a mic to the Macbook's 3.5 mm jack but cannot get that to work at all. Is there a mic input on the jack? What sort of jack, please? If I could use that, I could feed in a known signal from a waveform generator and see how that appears in Audacity. But I haven't managed to get that to work.