Desktop single-driver speakers?

I have enjoyed the Sony SRS ZX1 desktop speakers for many years, and am looking for an upgrade. These are small active single-driver speakers with a special «mobius duct» or C-formed extended bass port that makes them play more bass than expected from such small (7.5 by 3.1 by 7 inches) speakers (further described here: https://www.popsci.com/gear-gadgets/article/2008-06/secret-bass/ ).

They are great for nearfield listening at low-moderate volume, e g late night listening in my home office, not waking everyone else in our house, throwing a limited but high quality soundscape.

They benefit from the bass port – and even more, from the single-driver solution. I have experience with the Audioengine A5+, the Aurum Cantus 2 SE, and some small Elacs – all are two-way, and I give a plus to the one-way Sony ZX1 (even if this is otherwise a more limited speaker), for coherence, due to no crossover, but rather trying to solve problems acoustically.

In my system, including an OTL tube headphone amp into the gain chain (reducing problems with the s-state internal amp in the speakers), and some DIY stands raising them from the desktop, they have worked very well indeed.

I have looked in vain for upgrades from Sony, and have not seen much else in this way, either, from other companies. Maybe someone else can fill me out?

I am looking for single driver speakers with desktop or small monitor dimensions, preferably easy to drive for a low power tube amp. They can be active speakers, like the ZX1, or passive. The room is 12 x 9 x 7 feet, but I am mainly listening nearfield just 3-5 feet away from the speakers. I am looking for the best nearfield moderate volume sound, not speakers or amps that can «fill» the room with volume.