Just a reminder; I snugged the mounting bolts on all my drivers yesterday, and thought I got a new pair of speakers. Some of them required as much as a half-turn.
FYI: Don't over do it; just snug them, especially if you have plastic bezel rings around your drivers. I use the 2-finger rule, I snug the set-screw as far as I can using my thumb and index finger only.
Cheap tweak that makes a big difference, check them every 6 months.