For completeness and similar to the Exquis above, is the Akuto Chord Machine. It is also currently going through Kickstarter.
The keys can be isomorphic, or a two octave standard arrangement, or as seven groups of four chord types.
A major difference though is that the Exquis has MPE in two dimensions. Far as i can tell the Chord Machine has none.
Another wild alternative keyboard by Bob Moog, this one reinvented and restored !!!
How do you notate music for something like this. Good on Cornell for doing this.
ADDED : It occurs to me, this is exactly the sort of situation, a recreation supported by a major university and some passionate creators, of a project from fifty years ago, by a person long deceased, that might be made at least partially open source. One could hope anyways.
AND MORE : Found another better article on this from CDM. The synth in this uses a divide down technology.
And even a better article :
A guy I know is selling this Janko monstrosity, can’t be expensive. I’m half-tempted, but no, I’m not buying it, haven’t even bothered to ask about the price.
This is MPE with 61 multidimensionally sensitive keys and an isomorphic note layout (closely related to the Wicki-Hayden layout).
This is mostly a one hand thing, sure you can use both too, but with its compact arrangement you can span octaves with one hand. See image :
They have implemented alternative tuning methods and have a double keyboard ( called Duet ) in development.
Still made ( and available as best as i can tell ) and reasonably affordable.
An interesting discussion of an alternative (symmetrical) keyboard layout
https://www.le-nouveau-clavier.fr/english/
And an interesting demonstration of the concept
Makes a lot of sense!
Midihex from Gullsonix.
This comes in kit form. More info at their website.
I see they will be exhibiting at Syntheast in Norwich Feb 21 - 23, 2025.
They list their expansion plans :
Once the basic version has been established there are plans for further models with expanded keys and controls, and built-in sounds.
The source code is open source, which allows for customizing key layout. The potential exists to implement MPE.
Just came across a nice video explaining the benefits of the Janko layout:
