Re: Descending aug and dim intervals

"Joey Goldstein" <nospam@[EMAIL PROTECTED]
> wrote in message 
news:ftjv2q$tao$1@[EMAIL PROTECTED]
>I can't believe that this is stumping me, but I guess I haven't had to 
>think about this stuff since being a music student myself.
>
> Cb up to E is an ascending augmented 3rd interval.
>
> But, is Cb down to E a descending "diminished 6th" interval?
> I think that's probably correct, but it seems really weird to me.

Yes.  Complementary intervals which add to a perfect octave are

perfect+perfect  (eg 4+5)
major+minor   (eg 3+6)
dim+aug  (eg 3+6 as you have said)

> Likewise, C up to Fb is an ascending dim 4th interval.
> Is C down to Fb a "descending dim 5th"interval?

No.  C down to Fb is a descending aug5.

aug5+dim4 = perf8  (it obeys the rule!)

> C# up to Eb is an ascending dim 3rd interval.
> Is C# down to Eb a descending aug 6th?

Yes dim3+aug6 = perf8

> Or is my brain just doing tricks on me because I'm tired?

The Fb was the low point.  The rest is all fine :-)     It is actually a 
remarkably beautiful structure.

Dave
-- 
David Webber
Author of 'Mozart the Music Processor'
http://www.mozart.co.uk
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