Text and diagrams © 2001 by Joseph L. Monzo with helpful
comments by Paul Erlich (This page is accompanied with audio of
the beginning of my version of Mozart's 40th Symphony in
G-minor, K. 550, tuned in a subset of 55-EDO.) It is known that
Leopold Mozart taught his son Wolfgang to use a meantone tuning,
where "flats" would be higher in pitch than "sharps". There is
no documentation as to exactly what this tuning was, but there
are a few clues. Paul Erlich quoted in Yahoo Tuning List message
24125 (Thu May 31, 2001 9:03 pm) from Chesnut 1977 as follows:
Leopold Mozart refers to Tosi in general terms as an
authoritative source in a letter to Wolfgang from Salzburg dated
June 11, 1778. Tosi, in 1723, considered the correct tuning
system to be what we would today call a form of regular meantone
temperament ... according to Tosi, the large diatonic half step
is theoretically equal to five ninths of a whole step, and the
small chromatic half step is theoretically four-ninths of a
whole step. Tosi thereby divides