# Quick, and probably redundant interval question

Discussion in 'Music Theory [DB]' started by i like tictacs, Jan 3, 2005.

1. ### i like tictacs

Feb 2, 2004
LA, MA, FL
Right now, I am away from school and left my music book at home, like an idiot. My assignment for the week was such, from my teacher:

"Then write a short, 8 measure piece based on only one interval, using all of its qualities. For example, if you chose thirds, you could use major, minor, dim and aug."

I just wanted to double check to see that, if I were to choose A, the maj, minor, aug and dim (higher pitches) 3rds would be as follows:

M3rd: C
m3rd: Cb
d3rd: Cbb
a3rd: C#

I can't believe I'm asking this, and I drew a total blank, but it happens.

2. ### godoze

Oct 21, 2002
a to c# = major 3
a to c = minor 3

never heard of an Augmented 3rd; that would really be a diminished 4th.
Same with a Diminshed 3rd; that would really be a Major 2.

If you are going to do such an excersize why don't you use the compund intervals of a 3rd also ? major 10th, minor 10th ?

3. ### i like tictacs

Feb 2, 2004
LA, MA, FL
Agh...Yeah. I'm being a music dufus right now. Anyway, I have no idea why my teacher said augmented 3rds and dim 3rds, it's a basic theory class.

The dim 3rd of A would be to Cbb and the aug 3rd would be Cx, then? or C##, whatever suits you...

4. ### BassManJim

Dec 16, 2004
Southern California
Augmented and diminished 3ds are only used to maintain continuity within a key signature, to keep the interval mathematically correct. Any interval of a 2nd, 3d, 6th, or 7th can be major, minor, augmented or diminished.

Sometimes you will see them in classicsal pieces. But they are rarely used in the "real world".

Your instructor is doing right by you for introducing the concept though.

If you go on to advanced theory these concepts will help alot!

5. ### godoze

Oct 21, 2002
I have rarely ever seen them in classical music. Never once while I was in conservatory being a theory major did anyone EVER ask me to use one of these so named intervals.

Can you please give me an example of a scenario in which a diminshed 6th would be used to "maintain continuity ?"

6. ### i like tictacs

Feb 2, 2004
LA, MA, FL

Thanks - I know that my instructor is VERY into classical music and compositions. He's a real purist. I'm just a slab player looking to get more of a grip on the stuff.

7. ### BassManJim

Dec 16, 2004
Southern California
I am not a theory major, however, this is my humble understanding of the matter.

These correctly named intervals exist because, even though a perfect fourth and an augmented 3d are enharmonically the same, they cannot be written the same as their mathematical distances are different.

The augmented third must look like a third, and the perfect fourth must look like a fourth.

In other words, the third degree of the the scale is still the third degree of the scale, regardless of its quality. If written otherwise it would be chromaticism (not that ther's anything wrong with that).

As far as classical pieces go perhaps rarely is a better choice of words than sometimes.

8. ### Tom Baldwin

Aug 3, 2003
MD / DC / VA
No, no, no, and no. You are a half step low in each case.

C#
C
Cb
Cx

Augmented 3rd is enharmonically the same as Perfect 4th. Diminished 3rd is same as Major 2nd.

It doesn't matter if you never see this in the "real world". The point is it's an exercise or puzzle to help get your brain to understand intervals from a theoretical perspective. How many times in the "real world" do you hear a 3-octave major scale or arpeggio? And yet we practice these, because it's good exercise, which solidifies basic building blocks of technique and musical understanding.

9. ### nypiano

Feb 10, 2003
NYC
It's involving the inversion:
The diminished interval inverts to the augmented.
The augmented 3rd would invert to the diminished 6th. An aug3 could occur in a scenario where you modulated from C to F# and spelled the leading tone to F# as E#. If you inverted the E# interval that would be a diminished 6th. I think things in more recent times are written more enharmonically while in the past there might have been a more bullish effort to maintain the original key signature and related signatures and the appropriate spelling.This with the idea that the leading tone being the tone below at all costs even when reading/accounting for became complicated (ie FX in key of G#minor).