Good morning, first of all I apologize if I am posting in the wrong section.
I don't understand the difference between diatonic and chromatic semitones: if we are talking about a chromatic semitone when two notes have the same name (vice versa for the diatonic semitone), for example C - C#, wouldn't it be enough to write one of the two notes differently to change the name of the semitone? For example, C - C# and C - Db are the same interval, but the first is a chromatic semitone and the second is diatonic. Am I mistaken about something?
If I understood correctly, within a whole tone interval there is always one diatonic semitone and one chromatic semitone. For example, the C - D interval can be decomposed into semitones in two ways: C - C# C# - D or C - Db Db - D. In each of the two cases, there will still be one diatonic semitone and one chromatic semitone.
Do-sharp and do-flat re-flat are not the same interval. They have different distances. A tone is composed of nine commas, that is, nine small parts. In equal temperament, for us pianists, we have only one key for C-sharp and for D-flat, but in the natural scale it is not so. The violinist well knows the difference. However, when playing the tempered scale accompanying a Beethoven sonata for piano and violin, they make the two sounds coincide. The two semitones overlap by a small part: one has five parts and another has four. In equal temperament, they only change names. In reality, chromatic and diatonic are not two perfectly equal intervals.
