operation below fs

[REK]

...back from holidays...

BTW: Why is the low cut of the power amp relevant?
As long as it is much lower than the room modes it should not affect the booming. (I think..)
In my case the power section will be a DC coupled class D amp.

Depending on the application, I plan to have a 6th order 1db ripple tschebbychef around 8 or 9 Hz - cutting off the subsonics. And additional may be a 'party power filter', = 2nd order butterworth below 40Hz, in order to allow high SPL without exceeding Xmax of the speakers.

I recommend having flexibility in setting the low frequency cutoff. From my experience, setting the control at a higher frequency than 9Hz removed some of the rumblings and thuds of door slams in CD's and DVD's that I played. There is one DVD movie that I saw that had the woofer cones moving below 4 Hz. If your going to strive for reproducing all that is on the disc, I recommend not limiting yourself to 8 or 9 Hz. There is plenty down there to experience.