It is supposed to be there and it makes the sub sound very smooth and rich, much more life like IMO at least with music. For movies it still sounds very good but it seems to detract from that initial hit that you get with the other subs, Just my opinion though.

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