The cFCFAb tuning is one I came to after trying a more standard minor (fCFAbC) or sawmill (cFCFG) tuning. I use a Pythagorean temperament based on F which doesn’t change the tuning of the C’s and F’s very much, but makes the Ab significantly flatter than an equal-tempered Ab.
The whooshing, windy sound throughout (heard prominently during the intro) is generated by walking on a pair of foot pedals, almost the way you would pump an old pump organ. (You can see this motion in the video.)
While recording, I kept missing the foot pedals and accidentally stepping on a mic stand instead. I decided to embrace the resulting bass drum thumps and include them in the piece.