NC 700 Ringing noise on the right
I have a weird problem with my NC 700: On the right side, there is a (sometimes) ringing noise (high pitch) and a rattling noise when high volume/low frequencies.
According to my observations: The ringing only occurs when ANC is enabled (independent of the amount of ANC). The rattling is independent of the ANC.
The ringing is only heard when the headphones are worn (or when I close the cup with my hand). The rattling is only there. Sometimes I can fix the ringing and rattling completely (weirdly until I shutdown the headphones) by hitting/tapping the right ear cup with my hand.
I'm aware of the dust-in-outer-microphones and I have used canned air to clean them. But it makes no difference.
I have disassembled the right cup to check if there is a particle on the driver or something but could not find anything. I suspect that there is something wrong with the microphone in front of the drivers, as this microphone is probably to filter feedback and my issue seems to be feedback(?). The PCB is not very well attached to the holder, only the glue on the MEMS mic (?) keeps it in place.
Are there any hints? I suspect some physical problem as tapping seems to fix things?
Ist dies eine gute Frage?