Hi Steve
Firstly I hardly ever get any cone movement at all.
I often do watch films at somewhere between -10 and -5.
I have watched WOTW "machine emerging" at reference without any obvious problems except abject fear.
With no house curve I have to listen loud to get any floor vibration. My SVS cylinder can shake the floor on solo piccolo!
This suggests that there is plenty of room gain. Over 20dB gain rising to 15Hz in the case of the cylinder!
The louvered panel is a permanent feature to keep off birds, prevailing sunshine and insects. The open area area is 5.5 x Sd. My IB enclosure is a glazed gable end and can reach 100F so I wanted to protect the divers from direct afternoon sunshine.
Careful listening tests on difficult material (classical organ) suggests no difference with the panel in place. Thomas didn't like the louvered panel either.
I should have tried an REW sweep without the Behringer boxes ages ago given the very early roll off. But having read the thread on non-spec IB15's I have assumed my own drivers have an Fs up around 35Hz. It would be nice to be proved wrong.
I am using the proper REW correction file for my new RS SPL meter.
My old RS meter was much more flattering. I used the correct file for that one too.
Now the (very) bad news: 150cu ft would completely fill the entire volume to one side of my glazed double doors. It just isn't going to happen! A sealed triangular enclosure 7 feet high x 7 feet deep x 7 feet wide in our sun room will never be acceptable to my wife. Or me, I'm afraid.
Thankyou for your interest, Steve.
I shall just have to find another way to turbo the bottom end of my IB.
If the REW sweep
sans CX and BFD proves nothing I shall just have build an opposed driver manifold and/or buy some
real IB drivers.