Sub-60hz hum/rumble on a condenser mic
This might be a little advanced for this sub forum, but I'm not sure where else to put it since it seems so rudimentary.
I'm getting a weird low frequency hum/rumble on my Røde NT-1a that varies from 2-30Hz. There's also some concurrent broadband noise, but it's at a way lower level than the main rumble. It doesn't matter where I am, or what equipment it's hooked up to – tube pre, MBox, at home base or on mobile recording gigs.
At the same time, I'm getting clicks and pops when the mic gets hit with relatively high SPL. I had a similar issue with a TLM103 where the mic would short and cut out for about 10 seconds before recovering; in this case it just pops, often irreparably even after judicious use of the pencil tool.
WHAT is going on?