I have a level 5 18, old style, d1. Wired to .5 on my American Bass VFL 200.1. The enclosure is 5.75 cubes and tuned to 34hz with 2 6 inch aeros. The amp is set properly with a dd1 and then my sub level is turned 10 clicks below where it was tuned at. But the sub stinks after about 30 seconds of playing it loudly. Any reccomendations? I was thinking about shrinking the box and extending the ports.