I've been having problems with my clip mics for a little while. I use the Audio Technica ATW- T1801 mics and seem to have a lot of problems with noise. The noise floor is higher than I would like anyway but intermittently I get a kind of "pumping" noise when any speech is delivered. This doesn't happen all the time which makes it even more of a pain.
Does anyone know if this is interference? maybe something wrong with the receiver? or maybe just old/bad mics? I'm not always here when the recording is happening so there could be an amount of user error in there as well!