Magnepan 3.7's versus 20.1's?

I would think this is simple. The 3.7s are updated and the 20.1s probably will be soon, so for now there are a couple of things the 3.7 *might* do a tad better - but the main quality that the 20.1s have is the push-pull force on the ribbon and quasi-ribbon, so dynamics are a lot better (assuming proper amplification).

Also, they removed the external x-over on 3.7, so I think (I'm about to start a thread on this) that the active bi-amp option is out with 3.7, while it is still available on 20.1, and active bi-amp will generally add to the more dynamic part of the equation for 20.1.

If (this is a big if) you play a test tone, or a single singer who sings in a range not used by the ribbon, and if that singer doesn't have a lot of dynamic swings, then perhaps the new quasi-ribbon will for today out-do the 20.1 which will most probably be updated soon with the quasi ribbon that started on the 1.7. Also, maybe not! Because the push-pull might make the old quasi better sounding than the new one as implemented in the 3.7/1.7. All conjecture.

There's no sign that the 20.1 is going to be updated in the near future. There are rumors about an anniversary edition Tympani but that's another story ...

New Tympani's would be absolutely incredible!!!!

New Tympani, that would be awesome, I might actually open up the strong box for those.

Interesting in knowing that the new Tympani would be available. I am using Tympani IV bass panel with MGIII driven by Threshold S500 for LP and T200 for HP with Bryston 10B STD and CAT SL1 Sig. MK2 in my 6x8 m (2.8m height) room; the sound stage is so big. Image is fantastic.
After having my first MGIII for more than 15 years, I am still enjoying to listen the Magie everyday. Now I have two pairs of MGIII, one pair of 1.6 that need to be fixed for the buzzes due to losing glue. However, the combined Tympani/MGIII system is best matching so far.