I'm trying to teach myself some music theory and I'm learning intervals. I thought I had the basics down, but apparently I'm missing something.

Why is this a major 7th & not an augmented 7th?

_________ Sorry about my art work. It's a B to an A#.
___#O____ My book says "when a major or perfect interval is raised 1/2 steps
_________ it's augmented. It's looks to me like there is 7 steps (B,C,D,E,F,G,A)
___ plus the 1/2 step. My book says it's a Maj 7th. I don't get it.

Thanks for your help. I'm new to the music theory thing.
in a b major scale, the a is already sharp, so b to a# is a major 7th(i know it might seem confusing at first but always think about your intervals as notes of a scale, so the b major scale has (FCGDA) that are sharp) In this case an augmented seventh is imposible, your B would need to be a Bb, and that would be another key (Fmajor key) where the A would be natural; be sharping this A you could get an augmented seventh! Hope this helps, feel free to ask other questions, its not like im studying music for nothing ! XD
Last edited by roybruno92 at Oct 22, 2009,
B -> C -> C# -> D -> D# -> E -> F -> F# -> G -> G# -> A -> A#
........1......2......3......4......5.....6......7......8......9......10....11 (1/2 steps)
11 Half Steps is right below being an octave, and the biggest interval beneathe an octave is a Major 7th

I will lay out half steps
1 - Minor 2nd (m2)
2 - Major 2nd (M2)
3 - Minor 3rd (m3)
4 - Major 3rd (M3)
5 - Perfect 4th (P4)
6 - Tritone...
7 - Perfect 5th (P5)
8 - Minor 6th (m6)
9 - Major 6th (M6)
10 - Minor 7th (m7)
11 - Major 7th (M7)
12 - Perfect 8th (Octave/P8)

You can't have any intervals in between these. Augmented and Diminished intervals past this are simply enharmonic intervals, which means another name for the same interval. An augmented 7th would simply be a perfect 8th.
The reason there are these multiple names for the same interval is the same that there's different names for the same note.
When you're writing out the note names for a scale, you can't have two of the same note name, even if you ARE playing (for example) an E and an E flat, you would say you're playing an E and a D sharp. So with these intervals, if you're looking at sheet music and you have an E and a D with a double sharp sign (which is an E) you would say you have an augmented seventh rather than an octave or a perfect 8th, because the actual note on the sheet is not on the E space, it's on the D line (this is dealing with treble clef, of course)

Now, I think everything I just said was right, but call me on it if it wasn't, I'm not an expert, just been working with theory for a while. Useful stuff...
Last edited by IROn 5L1nKY at Oct 22, 2009,
That's all great stuff. I'm beginning to understand (slowly). I really appreciate the responses.