The original idea has matured to BACCH which uses a more sophisticated algorithm but it costs $55000. Ralph wanted to keep it free for the public and there are many product out there using RACE. 3D Aria, AMTRA and others are among them based on RACE. 3D Aria looks promising but it is still being developed.
The latest research paper was presented in 2014. Ambiophonics is already a matured product and there is nothing much to add to it except perfecting the implementation.
http://www.ambiophonics.org/TechnicalPapers.html .
I listened to the demo's last night and while interesting I preferred the normal imaging as the more effect they added the more unpleasant it seemed. I didn't have time to experiment so I'll be playing with it again tonight.
Listening to surround music via DVDA or SACD sounds better to me thus far but of course requires more speakers. I have also listened to 2 speaker surround that companies are trying to produce in sound bars with small subs (well, they call them subs anyway) and the effect is much like the demo's I listened to last night. I can see buying a sound bar for a Condo or Apartment but only out of desperation for something, I know I wouldn't like it.
As somebody before stated, it's like a solution looking for a problem. Maybe one day they'll make convincing imaging using 2 speakers and a sub or just two speakers but I think we are a long way away.
This whole thing reminds me of what Bose claims, a system in a box, it does everything! Except it doesn't, I have yet to hear a great Bose implementation or any other that claims to do things not possible with two speakers.
Not trashing the technology (I am trashing Bose, openly and enthusiastically), just stating my opinion thus far.