with respect to bass, it takes quite a while to break these in. They have to be played loud (VERY LOUD) with a lot of low frequency energy. The longer you do this, the more they flesh out. So far I have over 150 LOUD hours on mine and they keep getting better, but it sure taxes everyone's patience when the walls, windows, doors and floors are rattling hour after hour, day after day.
One thing for sure is these do not require a sub, if anything, I would turn the bass down a bit if I could. I was originally using an 8 watt SET. It had plenty of drive, but was weak in the bass. So after 48 hours I switched to a TPA 3116 I have on hand and the difference in the bass and bass presence was astonishing. At 95 hours I switched back to the SET and bass went AWOL. So I would suggest "try" another amp or two if you can. You might be surprised.