The Last Breakthrough in Speaker Technology

What was the last major breakthrough in speaker technology? You may interpret "major" in any way you like. If you think the dimpled ports on your B&W speakers revolutionized the way you listen to music, or your time and phase-aligned drivers brought it all together, it's all fair game!
Drivers with no suspension (spiderweb) but larger voice coil connected to big flat disk (instead dustcap).

According to reviews it improves speed and linearity making sound similar to electrostats but very dynamic.
6 1/2" midrange uses ferrofluid for damping.
Many of my favorite speakers use extremely old technologies, such as field coil drivers (dynamic drivers that use electromagnets in place of permanent magnets). A lot of newer approaches to speaker design/manufacture sound pretty bad to me (e.g., ceramic coned drivers).

The major recent developments are really outside of the actual speaker/driver field, such as using digital signal processing integrated with the design of the speaker.

Outside of that, the big technological changes that I thought deliver decent sound are all getting pretty long in the tooth. Bending mode drivers (instead of the voice coil moving a cone that is suppose to be rigid and moving in one piece, the voice coil bends the cone and propagates a wave in the cone material itself), such as the Walsh driver and the much improved MBL variant, on such drivers can deliver pretty good sound. I've heard recent designs using Heil drivers that are promising too (Heil drivers are essentially planar magnetic drivers that have been pleated, like an accordion, so that sound is squeezed out between the pleats).
Larryi - there are some speakers that use drivers with underhung motor. Underhung is not very common because it uses very large magnet, but gives much lower distortions (better linearity). Example of such speaker is Adagio from Acoustic Zen. Sometimes tweeters are underhung to deliver better linearity at large displacements - like Morel Supreme.

I don't know why most of maufacturers use overhung drivers - perhaps cost.
I think speakers sounded a lot better with vintage AlNiCo magnets. Its nice to see AlNiCo magnets are starting to make a comeback!

While maybe not a major breakthrough Thiels 3.7 midrange is very innovative and well designed. It is my personal reference point for purity of midrange and vocal reproduction.

As an R&D/Process Engineer (Mechanical by degree) I see a lot of ideas and designs, and lots of them flop. Jim Thiel not only had great concepts but fallow through to make them really work in the real world. Now that is true genius.
3.7 midrange paper
Vandersteen Audio has more than a few
Cheers Johnnyr
Martin Logan's curved electrostatic panel.
Actually, Roger Sanders invented the curved electrostatic panel.

Martin Logan did bring it market successfully.