Its a 15" RF HE2 DVC Sub in a 71 litre box with a 11cm diameter port 23cm long.
Thinking of sealing the box. As its ported at the moment.

Sub Specs:
QTS 0.506
VAS 236 L
FS 22 HZ
LE 1.85 mH
QES 0.55
QMS 6.4

Can someone do a WinISD Plot and help me with my box problem as its not sounding as good as i want. i want the best sq i can get from it.

Yea it's pretty peaky in the box vented, seal it and see how you go, if it still sounds a little boomy stuff the box with a 500g bag of polyester fiber fill.