Makizou, I finally did it.

[GM]

'Sounds' like the driver's specs are way off, so about all you can do is either get correct enough drivers and/or add however much damping is required to smooth them out with the understanding that they may become little more than a large sealed alignment with a minor amount of extra LF gain BW.

Anyway, for starters, make sure there's no air leaks, then try ~heavily stuffing the filter chamber [driver back box] and report back.

GM

 

[James189]

Thanks for the advice, the sides and speaker front panel weren't glued on, just clamped reasonably tightly but I'll get on with attaching that and then see where I'm at.