he's talking about music that existed before the technology of precisely measuring out the square root of 2 as the value of the semitone.

Music that doesn't use that mathematics didn't go away after it was invented. And it took a long time before anybody could use the mathematical ideal of ET at all - the technology to measure irrational frequency ratios in practical situations didn't exist.


The idea of closing the circle of fifths by 12-tone equal temperament has exactly as much rationale in traditional music as closing it by 19-tone, 31-tone or 53-tone ET, i.e. none whatever.
It sure does. They've built 31-tone keyboards and they've discovered that while it sweetens intervals currently a bit dissonant in 12-tone, it made other intervals even more dissonant, In fact, the perfect 5th becomes more dissonant in 19-tone and since it plays such an important role in music, we don't want to worsen it.

19-tone ET is a very close match to one of the meantone temperaments commonly used in Baroque music. You don't need to have all those notes on your keyboard to use it; if you're staying on the flat side of the spectrum you can leave the sharps out, or put up with a badly out of tune enharmonic if it only occurs rarely.

53-tone ET is the standard framework used for Turkish art music, but again no instrument ever has all 53 available at once.


and it seems it blocks off your perceptions so you can't even hear the sound of a mouth organ right
I agree with Don here. You're talking differences too minute for most people to care.

These differences are not subtle. There is a reason why diatonic mouth organs sound much richer and louder when playing diatonic music than chromatic ones; the pure thirds ring out far more clearly than the muddied ET ones you get on a chromatic instrument. Which is why you don't do much chordal playing on a chromatic.

It seems the first commercially available ET instrument was the Broadwood piano as tuned by A.J. Hipkins in 1846, with Chopin's style in mind. And it would have been some time before there were enough piano tuners trained in his methods to keep a piano in ET after it left the factory, if it was a long way away. And the first use of a modulation right round the "circle", as far as I can see, is in a late Beethoven quartet from the 1820s. Concertina makers only started advertising ET tuning for some of their products in the late 19th century. ET is much more historically recent than most people think and has only been the a technology composers could count on since Schoenberg's lifetime.