I am in the process of doing a theory assignment for school when i came across this interval i have to name the interval is G and Dbb is that a perfect 4th or a doubly diminished 5th?
Quote by notsojoeyb4eva
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Some kind of G to some kind of D is always some kind of fifth. So I'd go with ♭♭5

It's a bit of a trick question though I can't think when you would ever use that instead of P4. (EDIT: Apart from in an assignment with a trick question)
Si
Last edited by 20Tigers at Nov 19, 2009,
... the 5th is perfect, as a double flat it makes an enharmonic equivalent of C which is a Perfect fourth. Seeing as how the 5th is perfect on semi tone down make it diminished so what is the name of the interval its not double flat because thats not an interval name
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Last edited by acdc_rocks_1992 at Nov 19, 2009,
It's a perfect fourth. And "double flatted" is used to describe the 7 in fully diminished chords.

Ex. R b3 b5 bb7

-g13
Double diminished 5th. G to D has to be a 5th. It could come up if your playing something with lots of D flats and at some point you lower that scale degree to move towards C flat. This is what causes the double flat 7 in the fully diminished 7 chord g13 was talking about. In fact, the interval between the third and 7th of a diminished 7 chord is a double diminished 5th. So it happens alot.
Quote by MusicThinker
In fact, the interval between the third and 7th of a diminished 7 chord is a double diminished 5th. So it happens alot.
Might want to double check that fact.

The interval you mention (between the [minor] third and [diminished] seventh in a diminished seventh cord) is a diminished fifth.
Si
Last edited by 20Tigers at Nov 21, 2009,
Its a perfect 4th.

When talking about intervals a double flattened isn't the right term to use. Intervals are named only diminished, minor, major or augmented.

You cannot have a major or minor fifth or fourth. It is only perfect, diminished or augmented. The double flat does make it into a C. Therefor its a perfect 4th.

People are getting confused with the terminology used for identifying chords such as a double flattened 7th in a diminshed chord. Thats a totally different thing to identifying melodic or harmonic intervals.
Quote by richrowley
Its a perfect 4th.

When talking about intervals a double flattened isn't the right term to use. Intervals are named only diminished, minor, major or augmented.
no

Quote by richrowley
People are getting confused with the terminology used for identifying chords such as a double flattened 7th in a diminshed chord. Thats a totally different thing to identifying melodic or harmonic intervals.
Not really.
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It is a kind of 5th. I'm not sure if you'd call it double flat, double diminished, or something else, but it is a kind of 5th. The trick is that it is called a D, not a C (even though enharmonically it is the same, the difference is...I think diatonic would be the right word? Saying each letter note of the scale represents a different degree). I can't really think of any use for that besides an accidental, as MusicThinker says.
^It's not a perfect fourth because it's some kind of G to some kind of D which makes it some kind of fifth, - a double diminished fifth.

TS - I'm sorry I wrote it as ♭♭5 in my first post, you asked is it doubly diminished or is it a P4 so I used that to mean the double diminished fifth as opposed to the perfect fourth.
Si
Quote by richrowley
Its a perfect 4th.

This is completely wrong. Some kind of G to some kind of D is always a fifth. It doesn't matter if the interval is enharmonic to a perfect fourth. There are five letters in the interval (G A B C D), so it is a fifth. The quality of this specific interval is doubly diminished. Since fifths can only be perfect, diminished or augmented, lowering the top note by an additional half step makes this a doubly diminished fifth.

The best way to determine an interval is to count the number of letters first. This is by far the easiest way to determine the numeric value (unison, second, third, etc.). The number of letters is always equal to the numeric value of the interval. Once you have that, getting the quality is much easier.