Microseven M7WP-MIC microphone with Dahua42212TNI - buzzing noise

[Hellurei]

Actually it seems to be grounding problem that was causing interference. I took a speaker wire and attached other end to mic's body. Other end had to be grounded to one of the usb audio interface device's coupling. At the moment that seems to fix my issue. Earlier I really tried to ground microphone to everything and today I was just wasting time and playing around with the speaker wire.. couldn't believe that grounding has to be between microphone and usb audio interface..where is already rca cable connected. Hope this helps others out there. Without grounding audio might work few weeks and then suddenly start to buzz. I fixed buzzzing issue earlier without changing anything (it just stopped buzzing) but now it seems like this could be permanent fix.

 

[1.21 jiggawatts!]

on the Microseven M7WP-MIC, is there continuity between the 12v ground and the audio ground? if this is the case, it may be possible that any power adapter you use might inject noise into the audio signal due to the power adapter design. even worse, any noise on your AC line may pass through your power adapter, this can even be noise emanating from a neighbors electrical device which may be intermittent.

you can use a DC to DC isolated converter on the DC powering the mic such as this:

Isolated Module DC DC Converter 1 Output 12V 500mA 9V - 18V Input

https://www.digikey.ca/en/products/detail/mornsun-america-llc/VRB1212S-6WR3/16348221

it would be like having your mic connected by a battery. data sheet recommends a 100uf cap on the input and a 22uf cap on the output.