I talked about just intonation a little on May 27 when I presented some videos by composer Adam Neely. I found a thorough argument for the potential value of 'just intonation' in a video Nov. 2, 2020 on a channel called 'Sounds Good', titled prosaically Just Intonation vs Equal Temperament
Just intonation is, put simply, 'musical tuning based on pure intervals' (where the intervals are rational numbers, or ratios of whole numbers).
If you tune instruments of a digital piano with just intonation based on, say C Major, the other keys will very definitely have different personalities. With equal temperament in classical music, we say they do (D Major sounds regal, F Major sounds pastoral, B Major sounds massive) but that is our conditioning.
It also reminds me a bit of the different church modes.
Sounds Good discusses the ways instruments are tuned for just intonation. That is relatively straightforward with strings and electronic instruments.
One modern composer who has written larger compositions in just intonation is Ben Johnston (with the 't').
Here is his String Quartet #10 (1995), about 20 minutes. The post is by Pablo Ángel Zárate Pérez, and the performance is by the Kepler Quarter, in the Wauwatosa Presbyterian Church, in Milwaukee, WI (sorry, not the Pabst theater so popular with the libertarian group Mythinformed).
There are four movements. The first movement is conventional one in G Minor, with a climax at the end in G Major. The slow movement is a fugue that seems centered on D Minor. The scherzo is in C, and the finale is in G, and starts out as a fast waltz before settling in on an Irish folksong (Danny Boy) (also used by Sir Charles Villiers Stanford in his Irish Rhapsody #1) before suddenly dropping to a whispery ending.
Here is the video of the Stanford, Ulster Orchestra conducted by Vernon Handley (Chandos), license from PIAS.
(Posted: Thursday, June 2, 2022 at 10 AM EDT by John W. Boushka)