And when you’re recording bass frequencies such as kick drum or bass guitar turn the high EQ down on your mixing board for those channels. For example, if you have a 10k shelving EQ for the highs turn it all the way down. There’s absolutely nothing up there for bass tracks. It will reduce or eliminate and pumping and breathing artifacts, which are largely due to the high frequencies where tape hiss lives.
Dbx isn’t frequency dependent like Dolby, so when dbx expands to allow a signal through it opens up the entire frequency spectrum. You’ll hear tape hiss if the frequencies are all bass because there’s nothing there to mask the tape hiss on those tracks.