Why am I getting feedback and noise when my boom mic is unplugged?

The built-in microphones on Maxwell are directional, and when put in close proximity to the headphone driver, with sidetone on, they can pick up the signal and create feedback. This usually does not happen in normal usage situations when the headphone is worn. The feedback is similar to walking in front of a speaker with microphone in hand.

Feedback is due to sidetone gain on the microphone, amplifying the ambient sounds. Sidetone gain is necessary to provide the real-time voice monitoring users desire.

We implemented higher sidetone gain due to customer feedback that sidetone is not loud enough. However, this led to louder sidetone and higher prevalence of feedback, so in our most recent firmware update we reduced the sidetone gain slightly.

To prevent this feedback issue, either disable sidetone or turn off Maxwell before removing it from your head, or avoid placing Maxwell in such a way that the built-in microphones are very close to the headphone drivers (e.g. one cup rotated 90 degrees relative to the other).