Economies of scales

One more note about tunings. I first started to explore tunings in the seventies (I was a precocious High schooler) and the instruments I used most for exploration were simple metallophones made from aluminum conduit, modeled on those built by Erv Wilson. They sounded great but had one major drawback -- every distinct pitch I required required another piece of metal, and each new piece of metal has to be playable integrated into the instrument, which couldn't expand too much simply due to lack of space. You can probably imagine how quickly a cost/benefit picture comes into view, with costs rising at an alarming rate. A Just Intonation array was plausible only as long as modulation was limited and my total pitch vocabulary was restrained; otherwise tempered alternatives showed advantages of which I sometimes took.

Nowadays, working primarily with electronic media for my microtonal work, the constraints on materials and space have become less critical, and theoretically I should be comfortable working with any number of pitches. In practice, however, I like to have some sense of or feeling for the entire pitch collection in a piece of music, and my experience, with Just Intonation, is that only feel in command when that collection has no more than 20-22 or so pitches. At the same time, and again, even though cost should no longer be a great concern, I find that the advantages of temperaments are rapidly outweighed by costs when the total number of pitch classes exceeds 20 or 22 or so. There is much to recommend a tuning like 31-, 53, or 72- tones to the octave, but the qualities recommended are largely those of Just Intonation, so I find that unless I absolutely need to extensively modulate pitch sequences, I'd just as soon tune in Just Intonation. And should I be interested in using functional relationships that are not available in a Just environment, it's fortunate that the equal divisions of the octave from 7 to 23 tones offer a substantial number of such functional possibilities at the cost of reasonably small total collections of pitches with which to become familiar.