A little introduction to diatonic Intervals and how to understand them


Some time ago, I still remember seeing things like the perfect fifth and wondered why it's

called 5th if it was actually 7 semitones apart from the root note. Or I wondered what a 3b

or minor third is. Stuff like that. If you've ever asked yourself these things, then this

might help you understand it more.

(One more thing, make sure you know how the notes work, there are 12 of them and how they

are called)

Let's get started. These naming conventions are all based on the C Major scale:

Observe for one that the C Major Scale only uses whole notes and not sharps or flats. The

notes 2, 3, 4, 5, 6, and 7 are fixed in intervals from the root note, in this case C. For

example, the third note is exactly four semitones away from the root note, thus it being an

E. This is universal no matter what the root note is. For example, in the root of E:

Root D#:
The same applies to all other notes, the 5th is always seven semitones away, no matter what

the root is:

Root A:
Root F#:

Knowing this, we can now delve further. 3b means the note is a minor third or flattened

third, 4# is an augmented fourth. What does that all mean? Simple, a minor third is a

semitone lower than a major third, in other words 3b is a semitone lower than a 3. In the

key of C Major:

Major Third:
Minor Third:
This also applies to any other root note, which is the amazing thing:

An augmented fourth means that the fourth note is a semitone higher than a perfect fourth,

or 4# is a semitone higher than a 4.

Perfect fourth:
Augmented fourth:
As always, this applies to any other root note as well. With this knowledge you can now

understand what Phrygian scale is, if it's formula is 1, 2b, 3b, 4, 5, 6b, 7b, 8. In the key

of C Major:

C Major:
C Phrygian:
Interestingly, if you apply the Phrygian scale to E, all the whole notes are included, see:

E Major:
E Phrygian:
See, all the whole notes (C, D, E, F, G, A, B,no flats or sharps) are in a Phrygian scale if

the root is E. This then what people mean if an E Phrygian scale has the same notes as a C

Major Scale. It all depends on what note you start and it's the intervals, the "distances"

between the notes that do the magic.

Here are the seven modes or scales:
Ionian - 1, 2, 3, 4, 5, 6, 7, 8 (All the whole notes starting from C)
Lydian - 1, 2, 3, 4#, 5, 6, 7, 8 (All the whole notes starting from F)
Mixolydian - 1, 2, 3, 4, 5, 6, 7b, 8 (All the whole notes starting from G)
Dorian - 1, 2, 3b, 4, 5, 6, 7b, 8 (All the whole notes starting from D)
Aeolian - 1, 2, 3b, 4, 5, 6b, 7b, 8 (All the whole notes starting from A)
Phrygian - 1, 2b, 3b, 4, 5, 6b, 7b, 8 (All the whole notes starting from E)
Locrian - 1, 2b, 3b, 4, 5b, 6b, 7b, 8 (All the whole notes starting from B)

Due to the differences in intervals, the all have provoke different sounds when played, for

example, Mixolydian sounds very happy, while Aeolian sounds sad and Locrian sounds tense and

evil. Grab your guitar and play them, just start from C and play all the whole notes to

listen to Ionian, then play all the notes from E to listen to Phrygian. For guitar player, a

little tab:

That's it to scales. Now to chords. These can be constructed in the same manner, if you know

how the chord formula is, the most common ones being Major and Minor.

Major: 1, 3, 5
Minor: 1, 3b, 5

Simple, no? Apply that to any Root, and you got it:

F Major:
C# Minor:
The rest applies to all other notes as usual. Oh, and btw, notes like 9 or 13 are basically

the same like a 2 and 6 respectively, only an octave higher than the 2 and 6. For example,

in C:


And that's basically it for now. Ask me to clarify anything, there are probably some errors

in my naming as well, some people call 7b a flattened seventh, some people call it a

diminished seventh and some more people call it a minor seventh. That's something that still

confuses me today, so I more or less stick to writing it in numbers, than naming them.

More info in the Wiki articles:
http://en.wikipedia.org/wiki/Musical_mode
http://en.wikipedia.org/wiki/Diatonic_and_chromatic
http://en.wikipedia.org/wiki/Heptatonic

This article also helps a lot:
http://www.ultimate-guitar.com/lessons/the..._arpeggios.html



Have fun in music theory, it's amazing, it's an art that can provoke just the right feelings

in the listener if you know what you're playing.

This post has been edited by Dead__Man: Aug 6 2007, 06:16 PM

thanks alot for your post, slowly digesting it in
i have no music theory and wish to study more on it and this is good for me
thanks again

if i may add another page:

http://www.petethomas.co.uk/jazz-theory.html

Brilliant page. More for jazzers but alot of harmonies are explained here in great detail.

Maybe this can be linked up to the music theory thread?

i've tried and it is awsome !! thx alot !

This is essential but basic stuff... at most Grade 5 on the ABRSM/Trinity School syllabus, I think.
From here on, you can branch into chord progressions and cadences.

great stuff bro

should we start a lessons thread so that such work wont get wasted?

i forgot most of the stuff i learnt from classical
but this was how i learnt the major scale formations.
one way of cos like shown is to remember the distance between notes to form a scale.

another way is start with a C major scale.
CDEF GABC.
notice its seperated into 2 groups.
taking the next group GABC and continuing on with the 3rd note sharp while keeping whatever notes were sharp/flat from before...you get...
GABC DEF#G, yea the G major scale.
take one step further with DEF#G...
you get DEF#G ABC#D, yea D major.
then...
ABC#D EF#G#A and so on and on.

using this way, you will know how many sharps each key is suppose to have without really having to think.
thats how classical guitar lessons are anyway.
start with the simplest of scales, then slowly progress higher up til you go blind and cant stand reading notes

Yeah, but I forgot most of it, also I wasn't really interested in music back then, till I picked up a gutiar and jsut felt the magic of holding a fretboard. And I only recently really delved into music theory once I started writing songs. Was sick of jsut playing random things and hoping it would sound good. Plus I also wanted to know how some songs can sound so sad, but be made of mostly major chords...

my goodness...
that method sure takes alot of brain power.
so how many sharps are there in a B major?
*starts thinking from Cmajor*

lol. reminds me of fourrier series calculations.

not really, you just take it one step at a time.
starting of cos ppl learn in C and G major, 0 and 1 sharp note.
then you go up to D, A, E which have 2, 3 and 4 sharps.
you of cos cant expect a total beginner to just jump straight there anyway

easier to see if you group them up...
then it becomes CGDAEBF# from 0 sharps to +1 etc.

circle of fifths anyone?

also when you started you had no idea what EADGBE was right.
but now anyone who plays abit can tell thats how the guitar is tuned.
and im sure everyone has memorised much harder stuff

This post has been edited by Everdying: Aug 9 2007, 12:25 AM