Last night I had to play a gig! Yesterday afternoon I installed OS 7.4.1 - the official release - again and everything worked fine during the gig.
I will update to 7.5 today again. To install 7.5.1 is no good idea because I recogniced - similar than NotScott: if you turn the LowShift away from 0.0 the old sound problem appears again. So let's wait for the next release.
Where are you playing gigs right now? Isn't everything shut down or is this the return of smoke filled speakeasy gigs!