[linux_is_nice]

> By the end of freshman year, I had significantly expanded my musical tastes and unambiguously had perfect pitch… for piano only. I find it highly unlikely that this was due to identifying microtuning differences;

I think the more convincing theory for instrument-specific perfect pitch is that one learns to recognize the timbres of the individual notes, not any minute variations in pitch.

> Don’t learn a non-C instrument

I would recommend against this because it severely limits your options for instruments to play.

[mrob]

Every instrument is a C instrument if you want it to be. "Transposing instrument" is a misleading name. They're really just instruments for which Western staff notation is conventionally written transposed. If you're writing all your own notation for your own personal use or playing by ear it's irrelevant. The transposition isn't part of the instrument.

[mdwhatcott]

Yeah, this advice doesn't hold up--even the OP mentions learning the clarinet, which is a B-flat instrument. I also play the clarinet and developed the same ability to detect each note by its timbre. I also think there is a kinesthetic element to each note--the way the instrument vibrates, the back-pressure or resistance you feel while playing, that becomes associated with the timbre the longer you play.

[linux_is_nice]

As a clarinet player myself, I think it's an instrument that's pretty unique in just how different the timbres of each note are, like Bb or an open G.

[mrob]

Recorders also have big variation in timbre (and volume) with different notes.

[dhruvrajvanshi]

> I also think there is a kinesthetic element to each note--the way the instrument vibrates

Interesting point. I had a similar thought about singing.

In theory, a good enough singer would be able to use their vocal chords as a reference. Unless their vocal range is changing on a regular basis, if they remember the highest piched note they can sing, they could refer to that as an anchor.