Something noticed about my AMT's is that 'played ' without a bass speaker of any size sounds like strangling a small animal...and they go down to +/- 500hz.....
Matching the 'speed' of an AMT (or a ribbon, small planars, and the like) almost requires crossing over to a smaller woofer properly. Hand over the sub-150hz and below to a decent sized sub to 'move' substantial amounts of air about....
I've found that adding a smaller (and lighter) Walsh to my larger ones makes a substantial difference to their response and to the general
perceived
'air' from them. 'Uncoupling' the 'top' fq radiator and using a smaller voice coil (contrary to the design of the F's and A's of the past) may be heresy but it does seem to work well.
(I'm not using a typical 'enclosure' with the larger Walsh unlike Ohms', new or old. Just a sealed tube; think 'acoustic suspension', to damp excursion...).
The Tweet Matters, basically. But what's 'below' completes the 'image'. ;)