First of all, helloooo just got here

I've had this bassreflex subwoofer with Seas P21REX/DD 8" for a while but was never really happy with how it sounded so now I'm thinking about a WO for them and need a little input since I'm pretty much a rookie.
It's for home audio in a farely small room so will probably also be used as a table, in the 36*24" (10" high for 8" woofers right?) version.

Simulation 4th order bandpass:


Specs:
Fs: 33hz
Vas: 68.9l
Qts: 0.37
Qms: 2.36
Qes: 0.44
Spl: 91 dB

I don't know if it's a bad woofer for these kinds of subwoofer horn boxes.. doesn't seem to go very low before rolling off so.. What do you think? ???

Also, not to get myself lost in this early stage, have i got the drawing-bit right?

Your drawing is spot on.

The second simulation, if correct looks better anyways.

The response may be slightly less sensitive, but it results in a larger flat response.  It begins dipping off later around 40Hz, where in a small room it is not unheard of to begin getting room gain.  So the drop off will be slower, if not close to none.  Resulting in a nice flat response.  I would build it, looking at its predicted response.

I would also build it because I absolutely love the design.  Can't get enough of it.  Its amazing, it will punch you in the chest, yet rumble your insides.