Diminished is important! Diminished size doesnt matter! Diminished is beautiful! Why am I hyperventilating? Okay, lets calm down and talk about diminished chords.
A diminished seventh chord in closed position has different four notes, each of which is separated from the other by a distance of three semitones. Having said that, it should be clarified that a semitone is the smallest distance between two notes on a piano and closed position involves the different notes of a chord being placed as closely as possible to each other. Here are three different diminished chords:
B, D, F and Ab
B#, D#, F# and A
C#, E, G and Bb
Practically speaking, all other diminished seventh chords are derived from the above. For example, D, F, Ab and Cb would have been the next diminished chord in the above list, had I continued with a fourth example. However, D, F, Ab and Cb contain the same notes as B, D, F and Ab (the first chord in the list above). The only difference is the order in which the notes appear and the spelling of one of the notes (i.e. B and Cb are the same note on a piano).
So why state a comprehensive listing of twelve diminished seventh...