How can these 2 chords be substituted for each other? A7 for C#dim Key of Dmaj
D e f#G#A b c
Banjo G tuning GDGBD
Marlin Answered question October 8, 2022
They are similar because if you sharpen the root in A7 you get C#dim7.
A7 notes: A – C# – E – G
C#dim7 notes: C# – E – G – Bb(A#)
It won’t always sound right when you substitute chords, it depends on the music. Some songs will work OK, some won’t. Often, the substitution is only used as a passing chord.
Jazzers use this idea quite a lot, but not as much in other genres.
It’s also used commonly in soloing. Play a C#dim7 arpeggio over an A7 chord it sounds quite effective. Remember, ideas like this aren’t set in stone. Do this in some songs or genres and will sound like crap.
Anonymous Posted new comment December 20, 2018
Thanks I will try that. The chord was thrown into I IV V vi viio progression for practicing keys. Other progressions do not include the dim chord 7. Interesting how one note sounds off. Bd progression , again the amin sounds more harmonious than the adim after a gmin.