when i turn my sub output on my HU all the way up to 12, i can actually hear the cone moving and it doesn't sound good, is this normal? i have my sealed 10" L5 with 300 watts and about 1/3 stuffed with poly fill. What are the "rules of thumb" when setting gain, crossover, and bass boost on my amp, along with poly fill levels. i guess i shouldn't expect it to sound perfect when its turned all the way up, meh