Just saw this announced through my local performing arts center for a mid October date. I will probably get tickets for me and my brother to go, since we went to the movie together.
The only true mix problem I noticed when I went to see it last week was the opening narration from Gwen, sounding muffled but intelligible if you listened closely. Once it shifted to in-scene dialogue between her and her bandmates, then it seemed fine. I think I noticed that muffled quality one...