I tighten my drivers yearly, mine have removable backs and all drivers are fastened from within.
Otherwise, you will need to remove them, I would do them all at once, perhaps adding bullet connectors in-line for easier access.
If insulation, you can remove existing, partially or all, and replace with polyfill, I got mine from Walmart, one small bag expands to a heck of a lot.
Once, when a woofer was facing down (speakers on 8" high open base, a buzz turned out to be a staple that had fallen out and landed on the back of the cone. i.e. you never know, just be thourough.