I've always had a very basic understanding of music theory (major/minor scale structure, basic chord struture) but am just now trying to dig in a bit further to improve my playing.

That said - I'm using a book and am in the interval section. While it makes sense to me to use intervals on an ascending basis, I'm not sure I quite grasp the purpose of descending intervals. It seems logical to me that descending intervals should follow the same notes in the root's major scale, just in a descending order.

However, the book shows the same intervals descending as they are ascending - ie - a 2nd descending interval is a whole step below the root, whereas it would seem if following the root's major scale it should only be 1/2 below (the same as the 7th note in the scale)

Does that make sense? Don't know that I'm challenging what the book is teaching - just not sure that I understand the practicality of why we need to know a major scale's intervals in reverse order (hence knowing everything else in reverse). I'm assuming though it IS an important part of music theory?
I can't tell if you get descending intervals or not. (What you're saying about them is unclear to me.) But, yes, descending intervals are an important concept in music.
Look at the line below:

C - * - * - * - * - * - * - * - * - * - * - * - C - * - * - * - * - * - * - * - * - * - * - * - C

C represents the note that we will use in question, in this case, a C note.
We will use the middle C note in the line above as our reference, with all *'s to the right of it ASCENDING, and all stars to the left of it DESCENDING.
All the *'s are the other notes chromatically ascending or descending from C.

From the Middle C, count two stars to the right. You are now on the note D, which is one MAJOR SECOND from the note C ASCENDING (going right).
Now do the opposite; count two notes to the left. You are now on the note Bb, which is one MAJOR SECOND from the note C DESCENDING (going left).

The confusion that you have is that the intervals are named chromatically rather than diatonically. The reason they do this is so that it is simpler to think about in the context of all 12 notes. Because the interval is the same distance CHROMATICALLY from the original note, it is called the same thing, even though one is "going down" (left on our line) and the other is "going up" (Right on our line).

C - Db - D - Eb - E - F - Gb - G - Ab - A - Bb - B - C - Db - D - Eb - E - F - Gb - G - Ab - A - Bb - B - C

C descending to the nearest Bb is a major second descending interval, C ascending to the nearest D is a major second ascending interval.

Below shows what the intervals are called regardless of the starting note. Going down 2 semi tones from an A to a G is a major second, as well as from an F to an Eb etc.
Go right or left one star - minor second
two stars - major second
three stars - minor third
etc.
Last edited by macashmack at Apr 16, 2014,
intervals don't necessarily have anything to do with keys/scales, it's just a distance between two notes. perhaps the book is simply teaching you to recognize intervals regardless of which direction they're going, regardless of scale.
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Thank you macashmack...makes perfect sense. I was looking at it from the standpoint that both ascending and descending had to pertain to a certain scale or notes within that scale. But it IS purely interval based.
Quote by Mole351
Thank you macashmack...makes perfect sense. I was looking at it from the standpoint that both ascending and descending had to pertain to a certain scale or notes within that scale. But it IS purely interval based.

Yeah, I actually would advise you to forget about scales. What I mean is, intervals are actually more important in a lot of contexts. Scales have their use, but the main thing to worry about is intervals. A lot of younger musicians (guitar players especially) seem to get caught up in learning tons and tons of scales. That's great. But what's more important is how notes relate to the tonic. A b7 describes how far away that note is from the the tonic (aka "1").

Does that make sense?
Quote by crazysam23_Atax
Yeah, I actually would advise you to forget about scales. What I mean is, intervals are actually more important in a lot of contexts. Scales have their use, but the main thing to worry about is intervals. A lot of younger musicians (guitar players especially) seem to get caught up in learning tons and tons of scales. That's great. But what's more important is how notes relate to the tonic. A b7 describes how far away that note is from the the tonic (aka "1").

Does that make sense?

B7? That's the second highest note on a piano!
Quote by Mole351
I've always had a very basic understanding of music theory (major/minor scale structure, basic chord struture) but am just now trying to dig in a bit further to improve my playing.

That said - I'm using a book and am in the interval section. While it makes sense to me to use intervals on an ascending basis, I'm not sure I quite grasp the purpose of descending intervals. It seems logical to me that descending intervals should follow the same notes in the root's major scale, just in a descending order.

However, the book shows the same intervals descending as they are ascending - ie - a 2nd descending interval is a whole step below the root, whereas it would seem if following the root's major scale it should only be 1/2 below (the same as the 7th note in the scale)

Intervals are not functional. That is to say, they don't relate to a key center. They specify the relationship between two notes, regardless of where those two notes are individually.

If you go up a major second, and then go down a major second, you should end up in the same place, because a major second is defined as two semitones.
Quote by rob904
B7? That's the second highest note on a piano!

Um...not B7 the note.

"b7" as in the flatted seventh interval.
interval is just a measure of musical distance. It's like a foot is a foot is a foot, no matter which direction it's going.
Quote by macashmack
Look at the line below:
C-Db-D-Eb-E-F-Gb-G-Ab-A-Bb-B-C-Db-D-Eb-E-F-Gb-G-Ab-A-Bb-B-C

The confusion that you have is that the intervals are named chromatically rather than diatonically. The reason they do this is so that it is simpler to think about in the context of all 12 notes. Because the interval is the same distance CHROMATICALLY from the original note, it is called the same thing, even though one is "going down" (left on our line) and the other is "going up" (Right on our line).
Beautiful explanation!!
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