I wouldn't say the 400 packs a wollup, it does reproduce notes down very low faithfully but does lack the punch of the bigger drivers. When I compared it to my 10" 200 watt 12yr old sub, my sub shook the house much better than the 400, but the 400 produced sounds much more musically and sounded fuller. The 400 is a great sub for a music only system but I wouldn't recommend it for any form of HT use except in special circumstances where rattling things isn;t desired.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70