Ah ok I got ya. haha I didn't think of that. So no hissing then =) Hmmm that makes me rethink where I got the hissing though...I think its because I was thinking of pairing the CLAS R/MKIII. I think that the MKIII may be what may cause the background hiss. I don't currently have these but I am reading around looking for something to use with my CIEMs.