Again, we need to remind people of what Dennis Murphy pointed out, sealed enclosures and acoustic suspension are not the same thing.
An acoustic suspension system uses a high Qts driver, with a very floppy suspension where the bulk of the restoring force comes from the air in the enclosure.
High Qts drivers have fallen out of favor and well they should. It is just that years ago, there were a lot of misaligned speakers from the Far East and the US. The acoustic suspension speakers sounded tighter, but not as good as speakers using much lower Qts drovers, either ported or sealed.
Using a high Qts drover does gets you a lower Fs in sealed enclosure. However I have a heavy bias against high Qts drivers. Another good reason not to like them is suspension sag, gap rub and unreliability.