HERE IS A DARING PROJECT FOR YOU
From memory, the cabinet width of the L100 is just slightly wider than the 12" woofer. So, this idea for a rear mounted sub-woofer is 12" limited.
What you do is find an Auto sub-woofer with moderate sensitivity, low Fs, low Qts, high Xmax and decent power rating > very doable these days.
You cut and mount the sub. reverse style > magnet out, on the back of the enclosure. (this slightly increases the enclosure volume)
Without changing any existing XO components, you drive this sub. with a high mH inductor that has high DCR. The rough start is 12mH @ 6ohm DCR.
Although experimentation is needed, like stuffing or blocking the existing port, what you have created is a "Large low frequency Power Assisted port".
The rear mounting not only provides 'out of sight' modification but can provide 'near room corner', some very low frequency gain.
This described scenario CAN provide quite astonishing lower-bass output & extension. The phase orientation of the rear sub. is audibly obvious.
PS.
Due to the high DCR of the inductor, price doesn't become prohibitive 🙂
