Free speaker tweak that's a must do

I would suggest using a non-magnetic screwdriver. Some driver magnets are surprisingly strong, and can seem to reach out and grab a screwdriver, leaving a punctured driver in it's wake.

I never ever had a issue with it. And I've owned 100s of loudspeakers. Built many more. Most can and do play at SPL Polks could never approach. I do know once you've over torqued a fastener your going to have it loosen up and this is what Polk432 is probably experiencing.

I remember this happened all the time with the ProAc speakers I used to have. Never occurred to me to use something like Loctite on the screws :-(

Don't use red loctite or you'll need a blow torch to loosen them again. stick with blue stuff

Ed...this isn't always a good thing. For instance..the B&W 800 series drivers are mounted loose with the use of foam plastic gaskets. By tightening the drivers, you squash the gaskets and the speakers are not operating as designed.