[jancsika]

So people with perfect pitch often complain about headaches when, say, a choir starts to lose pitch. This is because they can hear how the pitches sung by the choir have drifted away from the pitches notated on in the part they are reading from. That knowledge can apparently be quite distracting.

However, I have never heard a student with perfect pitch complain or even inquire about internal inconsistencies in tuning that would lead to comma drift. E.g., "Hey, I was practicing singing C-G-D-A-E-C and I ended up slightly off from the C I started with. What gives?" I've never heard of a student stumbling upon anything like this independent of reading a text about the problems of tuning systems.

[humbledrone]

People without perfect pitch (even non-musicians) can often hear that an equal-temperament major triad is a little bit more dissonant than a just-temperament major triad: https://www.youtube.com/watch?v=AcCkn0p7HDE.

I don't have perfect pitch, but as a guitarist I often tune my 3rd string to be a little bit flat (relative to equal temperament), because many chords I play have their major 3rd on that string and it sounds better to have it closer to just temperament.

Regarding singing, one of the reasons that Barbershop music has such a beautiful/smooth sound is because the vocalists sing the intervals of chords in just temperament, despite the fact that the bass note moves around in equal temperament. This is covered well by the Wikipedia page: https://en.wikipedia.org/wiki/Barbershop_music.

[jancsika]

The Barbershop example is orthogonal to what I'm describing. There, the singers are (apparently) choosing to sweeten particular chords to get certain relationships in the partials. That's something you can listen for and hear without having perfect pitch.

What I'm saying is that there seems to be a disconnect between the various theories of tuning systems and the way humans perceive melodic interval distances. It seems like people who have perfect pitch do a good, consistent job of organizing their memory of sounds into frequency bins. It also seems like what they are not doing is memorizing an idealized set of integer ratios-- or even any interval relationships in particular-- and then singing those intervals back in melodies.

If they could do the latter then you'd expect them to sing those intervals in melodic patterns that end up on a frequency measurably different from where they started. People with perfect pitch obviously have the ability to know when that happens, but I don't hear them describe that conundrum. It makes me speculate that what they are doing is leaping around "frequency lily pads" from memory rather than iterating over a list of well-defined intervals.

[xscott]

It's odd - I've messed around with this kind of thing too, and while I can recognize the perfect intervals sound cleaner, I generally prefer some dissonance and waiver in the chords. Depending on the style of music, it just sounds more interesting to me.