To cut a long story short, I tune my own piano but the temperament of the tuning is not the commonly used “Equal Temperament”. It is significantly different and to my ear at least, has a more pleasing “harmony” than equal temperament.
From what I’ve read on the subject it appears that alternative temperaments generally only work for a subset of keys (as in key signature) though somehow what I’ve ended up with appears to work satisfactorily for all keys but I have no idea why. I have tried to mathematically understand why it works although what I ended up with as far as a model didn’t tie in with what I’ve actually tuned so it isn’t clear to me as to why it works.
I have created a video about it to see if anyone could possibly explain it. The video comes with a disclaimer though. I am not a professional piano tuner and my unisons (ie. tuning of each of the three strings per note in a piano to a common pitch) is not entirely accurate so you need to put aside those failings and just concentrate on the temperament (the relationship between the 12 notes in the chromatic scale from middle C to the C above). In fact, I’ve only tuned a piano perhaps six or eight times so I clearly lack experience in this regard. I have included a depiction of the tuning with a tuner app, the sound of the scales, sus-4, sus-2, major and minor triads and stacked thirds over two octaves to illustrate it’s character. I have also included renditions (with mistakes of course, as I’m no concert pianist – mainly mental blocks of memory) of a few classical pieces, namely, J. S. Bach Prelude in C Major BWV 846; Ludwig van Beethoven, Bagatelle No. 25 in A minor (WoO 59, Bia 515) ‘Für Elise‘; Jean Sibelius, Op. 27 nr. 1, ‘Elegi’; Chopin, Prelude in E minor Op. 28 no. 4.
If you have perfect pitch that is well trained on Equal Temperament (ET) then I guess you will come to the conclusion that it sounds out of tune. By definition, if it is different to ET then it obviously is, although this is based on an implicit assumption that ET is the only “correct” temperament, which, although well culturally engrained, particularly now with the presence of all myriads of tuners, synthesizers and other devices all tuned to ET, is not at all true, at least in my view it’s not. Indeed, there is a thought provoking book on this very subject by Ross W. Duffin entitled “How Equal Temperament Ruined Harmony (and Why You Should Care)” that is well worth reading. For solo piano I think I will always find ET somewhat troublesome because of the harmony it provides with certain chords and chord changes in many pieces of music I like to try and play.