I take it your in the car, driving it or is it doing it parked?
If the prior, there is a setting on most cars called GAL, can’t remember exact names or even if the QP has it but it has a setting where the faster you go...the louder the road noise, the volume is increased.
I find it annoying and always disable it.
If the later, I would suspect a short in the volume nob, maybe pull it, spray in some electrical contact cleaner and work the nob (oooh ehrrr)