Hello, I have a Fender rumble 410 cab that I use with my quilter bassblock 800. Lately I’ve been noticing that on the lower notes of the neck (E on 7th fret of A string and lower) just don’t have any low end. It sounds like the same tone but just turning the bass control all the way down. I’ve tried different basses and had the same issue, and also used the head with a different cab and the problem was no longer there, so it is the fender cab. Has this happened to anyone else? What could this be? Thanks.