Well... -5 on my dial is getting into earbleed levels, but I'm all dialed in for "reference" at 0 with Audyssey. That's really loud for movies, and very very loud for some music. An spl meter would tell us a little more. If you have a smart phone you can find one in whatever market or app store you use for free. They're not the most accurate thing you can use but can get you in the ballpark. That's give us a better idea of the volumes you're hitting.
Just going by the video, I know that by the time my 5 1/2" drivers are moving as much as yours with a 80 hz crossover it's really loud. Are you using a subwoofer right now? How did you set the crossover? It could be too, that your amp is clipping.