At the risk of being flippant, the first thing I would look for in my headset would be .....a wasp!
Not only will it drown the R/T, but it can really hurt too!
I bought some cotton ear-piece covers for my DCs, not only for hygiene, but also after I left them on the front coaming for half an hour in the sun......
Seriously, I bought DC 10-13.4s and I'm very happy with them, I also got them serviced under warranty too.