Bach Chorales

[pianohenry]

i know youre not allowed to have consecutive 5ths, octaves. its one of the main rules.

but are you allowed to have consecutive DIMINISHED 5ths?

e.g. in the right hand of part of the chorale:

Csharp          B                     C sharp
E          ----> E sharp -----> F sharp

so here the E sharp moves up to F sharp in the alto part, and the B moves to C sharp in the soprano part.

is this JUST as bad as consecutive PERFECT 5ths, and so should NEVER be done?
or is it NOT QUITE So bad, and can SOMETIMES be done?
or does is not count, so it can be used anytime?

[Bob]

I don't think a dim5 to P5 breaks the parallel 5th rules -- because they're not P5's.  So the example is fine (I think).  Of course, you say that's just the right hand, so the E, E#, F# probably aren't quite as important as the bass notes.

I'm not an expert on counterpoint.  I do remember a prof mentioning this situation.

And it's Bach, so he can do whatever he wants.  Bach makes his own rules.


Your first question doesn't match the example though -- can you do consecutive dim5's?  The example is dim5 to P5.

Dim5's would be a big dissonance for Baroque music.  They probably wouldn't do them consecutively.  The tension would need to be resolved.  I could be wrong, but I doubt they are present much in Baroque music -- consecutive dim5's I mean.

Music theory are just rules.  Sometimes they don't work.  Sometimes they have to be bent depending on what you want, what you consider most important and a priority to keep and not alter.

Consecutive intervals erode the perception of independent lines.  If it still sounds independent and it's consecutive, then it's probably ok. 

But again, I'm not a counterpoint expert.  I do know this question comes up in counterpoint.  I'm sure I've got it in a section of my counterpoint book.  It's not uncommon.  If someone else has their counterpoint book handy.... they could get the answer.

[pianohenry]

oh yeh, i see what you mean - i meant diminished 5th ---> perfect 5th.

ideally in my example, it would have had the soprano part going from C sharp, B, then down to A instead of up to Csharp again. but i have to harmonize them given the top line, thats the part i cant change

thank you for your help, that clarifies it a bit for me

[ramseytheii]

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