It’s doubtful just pulling a driver to check it out would void the warranty, but if you‘re contacting them anyway might as well ask. I would give it a listen close up just to see if you can hear where the problem is coming from. If it’s a bad driver they will probably just send you a new one that’s what happened when the dust cap on one of my M22’s drivers came loose. Or it could be something loose inside. I’d also listen to it off the wall. Just because it feels secure doesn’t mean it couldn’t still be vibrating against the wall.
