These are great starting points to thoughts. To some degree, all musical experiences involving more than one person are cross-cultural, because we all inhabit our own micro-cultures. So if we hear someone's performance and perceive it as "out of tune"—that is, not aligning with our habitual expectations about pitch and intonation—there are a few possibilities:
- We're experiencing a musical culture clash: The performance is actually "in tune" in a different tuning system. Perhaps it divides the octave differently, or alters intonation contextually in certain circumstances ("blue notes," "leading tones"), or actually values what we perceive as dissonant intervals (e.g. ganga). If we can enculterate our hearing to use the standards of the culture generating the music, we would perceive it as "correct."
- Perhaps the performer also perceives the performance as "out of tune," and wishes it were different. I do my fair share of playing out of tune on gut-string baroque violin, and can blame temperature, humidity, or (when I must) my own skill.
- Perhaps the intonation is not governed by any cultural convention—that is, it is "out of tune"—but the performer doesn't perceive it or is unconcerned. This is it's own kind of music-culture clash: The emphasis placed on being perfectly "in tune" is its own cultural value that isn't universal. Honky-tonk piano players, folk singers with guitars around a campfire, and many others might correct the most egregious of tunings but not bother if it's "close enough." Also, such "imperfection" might actually be sought out.
When I discovered Sufjan Stevens a few decades ago, there was a moment about 1.5 minutes into the album Michigan, when I actually said out loud to myself the words "aesthetic of imperfection." In the instrumental of "Flint"...
... the pair of instruments (both trumpets? is one a flugelhorn? not sure) are full of tiny flaws. Cracks at the start of notes, changing from one note to the other out of sync, slightly off intonation. Now, they could easily have done a couple more takes and thrown out the ones with cracked notes, and maybe even spliced together the "good parts" of multiple takes. I'm not suggesting that the notes are being flubbed on purpose
, but Sufjan is definitely not going out of his way to correct them. His overall gestalt has a "warts and all" approach that perhaps creates a sense of "authenticity"; this music is "hand-made" and of-the-moment, and the tiny flaws make it human. (Now, it's a separate question whether an overt pursuit of such "authenticity" is itself "authentic," or whether it's its own kind of affectation...)
In plenty of genres, there's such a thing as "too perfect." A blues singer pursues a husky, tobacco-cracked vocal tone, and even if he could sing like Josh Groban it wouldn't fit the genre.
So in listening to the music of others, it's hard to know which scenario you're hearing ("in tune for them," "out of tune for them," or "who cares") until you know more about their music and even the individual. But in your own music making, if you're intrigued by non-standard tunings, feel free to continue experimenting!
- For a string instrument with fixed frets, altering the tuning of the strings will of course have an impact, but no, is not the same as "playing in a different scale." On one given string, all the frets will still be the same distance apart. But if you can access an instrument with moveable frets, like the oud or lute, or a fretless instrument, then you can truly experiment with altering each note.
- I think I may have heard of the idea of, for an instrument with paired courses like a mandolin or 12-string guitar, of intentionally detuning one of the courses slightly. Supposedly this adds "bulk" to the sound, or a sort of chorus effect. I suspect what we hear more often is the fact that, even if you try, it's darn hard to keep 6 pairs of strings perfectly in tune! Some varieties of tiple even have tripled courses, 3 copies of each string!