Hunt’s performance both the use of an alternative keyboard and Just Intonation.
Here’s what Hunt has to say about the performance:
Here’s a rendition of Bach’s C Major Prelude and Fugue (opening) played in Just Intonation on a Tonal Plexus keyboard
Obviously, Bach did not write this music to be played in Just Intonation (the “Well Tempered” part of “Well Tempered Klavier” has a specific meaning for tuning), so this is an experimental performance which uses pure 3rds and 5ths, natural 7ths in dominant chords, and harmonics reaching the 17-Limit in diminished chords. In several places, a common tone can be heard to ‘bend’ from one chord to the next (usually in ii-V progressions) where a pitch has to move by a septimal comma; the pitch is changing in real time by JND steps.
This is a single take. I played only the opening of the fugue, very slowly ; ) This is for two reasons. First, so my fingers will behave and play the right keys, and second, so the sounds of Just Intonation can be savored a bit. Find out more about the Tonal Plexus at http://www.h-pi.com