There is an instrument called Axis which plays back in the Bohlen-Pierce Scale (13 note equal temperament). There are a series of videos on youtube about it, some of which get more technical I believe, but here is one where the player compares a lot of the intervals and chords with equal temperament:
I thought this would be interesting to post because I don’t believe we have talked very much about creating instruments with the primary purpose of exploring different temperaments. I find many unusual tunings like this to be very compelling.
I’m including below a bit of information from Wikipedia that I found useful in understanding the tuning:
The intervals between BP scale pitch classes are based on odd integer frequency ratios, in contrast with the intervals in diatonic scales, which employ both odd and even ratios found in the harmonic series. Specifically, the BP scale steps are based on ratios of integers whose factors are 3, 5, and 7. Thus the scale contains consonant harmonies based on the odd harmonic overtones 3/5/7/9. The chord formed by the ratio 3:5:7 serves much the same role as the 4:5:6 chord (a major triad) does in diatonic scales (3:5:7 = 1:1.66:2.33 and 4:5:6 = 2:2.5:3 = 1:1.25:1.5).