Today I am all caught up in the implications of a brief exchange with a musician about tunings of keyboard instruments before the era of equal temperament - put by Ross Duffin (How Equal Temperament Ruined Harmony and Why You Should Care) as 1916. This musician, who has perfect pitch, confessed that he can't really tell the difference between one temperament and another.

Do these minuscule differences matter?

It has long seemed to me that the piano is a kind of translating instrument: its pitch can be made compatible with all kinds of other pitches simply by respecting the specific ways in which instruments and voices tune among themselves and not getting in their way. It is ironic that so much early instrumental instruction is based on having children match piano pitch, when it should be the other way around: young piano students should be made sensitive to string and vocal intonation.

Recently I heard an a capella choir that was entirely out of tune with itself. The notes were all there and they were probably correct but, having been matched to piano pitch, they were entirely unconvincing.