Thanks for the info Robert. I have the BASSIS to boost the low end. It ends up being an expensive LT circuit. So if I do any boosting of the RL, I am afraid I will be hearing noises I did not expect.
I am using 9 dB and that is as much as the Tumult can take. Anything above that and when I run frequency sweeps, anything below 18 Hz and 12 dB of boost gives some mechanical noise.
I have been considering the thought Boomie brought up of getting two new drivers and move the Tumult to another enclosure. My problem is that I put a substantial amount of time in building the enclosures. Lots of cherry and a decent finish to match my main speakers. ( I attached a pic from when I was building them)
I have yet to find a better driver than the Tumult that meets the requirements of: 3 cu ft box, 1,400 watts and domestically assembled than the Tumult.
The LMS drivers are so expensive, even before TC changed their pricing. And need so much power. I keep hoping that someone comes up with a high excursion driver even better that the Tumult, but have yet to find one tht meets what I need.