Interval help?

[fsf347]

im kinda confused about intervals.

how come there arent any augmented 2nd, 3rd, 4th intervals, but there are for 5-7?

by the way, the intervals i have written down have C as the root, if that helps.

[headonastick]

The quick answer is: there are! An augmented second would be three semitones. It appears in the harmonic minor scale between the 6th and 7th scale degrees, although it is often referred to as if it's a minor third (which is also three semitones). An augmented fourth is a tritone, and is the same as a diminished fifth. An augmented third would be the same as a perfect fourth in terms of how many semitones it comprises.

[fsf347]

oooooh, true, i think i got it now haha.

one more thing if you dont mind?


lets say im constructing a major triad with C as the root.

would i say im using C, a major 3rd, and a perfect 5th

or

a C, a major 3rd, and a minor 3rd?

[onlyclave]

Originally Posted by fsf347

im kinda confused about intervals.

how come there arent any augmented 2nd, 3rd, 4th intervals, but there are for 5-7?

by the way, the intervals i have written down have C as the root, if that helps.

Ignore Headonastick's answer.

Intervals are measured from the lower of 2 notes to the upper. The distances between intervals is measured in numbers and quality.

The 5 types of intervals are major, minor, perfect, augmented and diminished.

If you expand or contract the distance between two notes using only sharps or flats then the name of the interval stays the same but the quality of it changes.

If you have a Major Interval and add a half step to it using a flat on the lower note or a sharp on the upper note it then becomes augmented. If you subtract a half step from the distance between the two notes it now becomes Minor.

Adding a half step to a Minor interval makes it Major, subtracting a half step makes it diminished.

A perfect interval becomes Augmented by adding a half step between the two notes and diminished by subtracting a half step between the two notes.

It is important to note that the actual note names do not change when you are changing the quality of the interval.

C - D is a major second
C - D# is an augmented second
C - E is a major third
C - Eb is a minor third

Notice that D# and Eb are the same note. These are called enharmonic equivalents and while the notes sound identical they are two distinctly different names.

So in summary, 2nds, 3rds, 6ths and 7ths may be major, minor, augmented or diminished depending on the distance between the two notes. The actual names of the two notes are determined based on the context they are being used.

4ths, 5ths and Octaves may be perfect, augmented or diminished.

A Perfect unison may only become augmented.

[onlyclave]

Originally Posted by fsf347

oooooh, true, i think i got it now haha.

one more thing if you dont mind?


lets say im constructing a major triad with C as the root.

would i say im using C, a major 3rd, and a perfect 5th

or

a C, a major 3rd, and a minor 3rd?

That is a root, major 3rd and Perfect 5th. When speaking of chords we relate all members of the chord to its root.

The distances within the chord are in fact a major third and then a minor third but that will change as soon as the chord is inverted which is why the intervals are related to the root.

[Jake of Bass]

How and when do you use an augmented or diminshed octave instead of a minor IX or major VII, and how does the application of a diminished IX work instead of an octave? This kind of thing has never been explained to me properly.

[onlyclave]

Originally Posted by Jake of Bass

How and when do you use an augmented or diminshed octave instead of a minor IX or major VII, and how does the application of a diminished IX work instead of an octave? This kind of thing has never been explained to me properly.

HaVIC5 probably has the real answer but I will say that the rules of diatonic harmony predict that these intervals are possible although they are strictly theoretical. In practice you wouldn't double the root of the chord with an augmented octave.

I believe it was Fuchs that classified the intervallic qualities as major, minor, etc. based on strong and weak consonances and dissonances. Octaves and Unisons (Primes) are special cases of Perfect intervals.

[headonastick]

Originally Posted by onlyclave

Ignore Headonastick's answer.

Strange. You seem to be agreeing with me that there are indeed augmented 2nds, 3rds and 4ths. What about my post was incorrect?

[nothumb]

Originally Posted by Jake of Bass

How and when do you use an augmented or diminshed octave instead of a minor IX or major VII, and how does the application of a diminished IX work instead of an octave? This kind of thing has never been explained to me properly.

most of the weirder augmented and diminished notes occur only in exotic theoretical situations or unusual scales, and the difference between an augmented 2nd and a minor 3rd, for example, is mainly just how you are thinking of the scale being played.

for instance if you are in Spanish phrygian (phrygian mode with a major 3rd, commonly E F G# A B C D), the interval of F to G# would be considered an augmented second and not a minor third because they are adjacent notes on the scale. the third of F in this scale is A and any F chord in this scale is almost always played as a major, even though the scale also contains the enharmonic equivalent of an F minor.

similar situations arise in whole tone scales etc and the difference is a matter of notation / theory in terms of how you conceive of what's being played.

[Jake of Bass]

Originally Posted by nothumb

for instance if you are in Spanish phrygian (phrygian mode with a major 3rd, commonly E F G# A B C D), the interval of F to G# would be considered an augmented second and not a minor third because they are adjacent notes on the scale. the third of F in this scale is A and any F chord in this scale is almost always played as a major, even though the scale also contains the enharmonic equivalent of an F minor.

Cool, that makes a lot of sense actually. I'd always wondered about that everytime I pick up a guitar and play Misirlou - love the scale but wondered about the name and intervals. Cheers.

It would always be played as F major because the A is a third away from the F, in relation to the scale.

Maybe I'm overcomplicating this, but if the F as root and the following chord tone of G# was used, would it be considered something weird like Fsus2, with the 2 being augmented, or is that just silly and it would be a normal Fm chord?

[onlyclave]

Originally Posted by Jake of Bass

Cool, that makes a lot of sense actually. I'd always wondered about that everytime I pick up a guitar and play Misirlou - love the scale but wondered about the name and intervals. Cheers.

It would always be played as F major because the A is a third away from the F, in relation to the scale.

Maybe I'm overcomplicating this, but if the F as root and the following chord tone of G# was used, would it be considered something weird like Fsus2, with the 2 being augmented, or is that just silly and it would be a normal Fm chord?

That G# in a F maj chord possibly could be called an Augmented 9th. Depends on where it's voiced and other chord members involved. I don't think I've ever seen a sus+2 chord because suspended chords really aren't part of functional harmony. A suspension is a nonharmonic tone that resolves down by step later in the bar.

[Jake of Bass]

But where would the third be, if G# was replacing the A as the third, but as scale degree it's function is an aug2? This is where I'm seeking clarification. It's entirely possible I could be dreaming up theory that doesn't exist, hence my question.

[onlyclave]

Originally Posted by Jake of Bass

But where would the third be, if G# was replacing the A as the third, but as scale degree it's function is an aug2? This is where I'm seeking clarification. It's entirely possible I could be dreaming up theory that doesn't exist, hence my question.

In a diatonic scale you can't replace A with G#. They both have to be in the scale

F G A Bb C D E F
F G# A B C# D E F
F G A# B C D# E F

Those are all "legal" scales because all of the letter names are in there.

If in a Fmaj chord you replaced the 3rd (A) with G#, I'd tell you that all you did was lower the 3rd and make a Fmin triad, F Ab C.

If you added the G# to said Fmaj triad, F A C (E) G#, I'd call that a +9. In this case I would use the '+' symbol instead of Aug to avoid confusion with augmenting the 5th.

[Jake of Bass]

Sorry, what I meant was with the example of the spanish phrygian scale.

E F G# A B C D

And the F A C being an F major chord. If the A was replaced with G#, in relation to the scale does this become an altered chord of sorts, for theory purposes? Or is it simply your standard Fm chord?

[onlyclave]

Originally Posted by Jake of Bass

Sorry, what I meant was with the example of the spanish phrygian scale.

E F G# A B C D

And the F A C being an F major chord. If the A was replaced with G#, in relation to the scale does this become an altered chord of sorts, for theory purposes? Or is it simply your standard Fm chord?

G# is still a non-harmonic tone. Triad, the root of the word meaning three, is based on stacked 3rds. If it is written G# it is a +9. If it is written Ab it is a -3rd.

If you really want to have sus2 and sus4 chords these are based in quartal harmony, which is stacked 4ths.

[Jake of Bass]

Originally Posted by onlyclave

G# is still a non-harmonic tone. Triad, the root of the word meaning three, is based on stacked 3rds. If it is written G# it is a +9. If it is written Ab it is a -3rd.

Oh yeah, that makes a lot of sense now. Should've realised it myself.

If you really want to have sus2 and sus4 chords these are based in quartal harmony, which is stacked 4ths.

I've never heard of quartal harmony, is it pretty in depth?

edit: never mind, I found a pretty comprehensive wiki article:

http://en.wikipedia.org/wiki/Quartal...uintal_harmony