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GMC Forum _ THEORY _ Modal Theory

Posted by: Barthandelus Jun 23 2014, 07:29 AM

Hi guys,
I have been working on scale modes for the past couple of weeks and although i now know the shapes of the modes, im confused on how they are related. For example, lets say im playing a riff in C major, and putting a lead over the top. How can this have the same notes as A minor? They seem to both have no sharps or flats, and i would therefore assume the same key signature? huh.gif

Going on from that, how do we know what mode a solo would be in? A 4 bar lick in Phrygian would have the same notes as Mixolydian? Does it really make a difference at the end of the day?

I guess i am getting confused on the actual use of the different modes. Note for note, they seem to be the exact same. If i know the major scale for a given key, what use are the other modes? smile.gif

Thank for your help on guiding me on this interesting subject.

Posted by: klasaine Jun 23 2014, 08:07 AM

Understanding how the modes relate to a 'parent' major scale is really important but that's only half of the game.
Let's take two very common chord progressions:
1) Am - D one bar each chord, repeated over and over.
2) Am - Am - F - G one bar each chord, repeated over and over.

Both of these progressions use an A minor type mode but not the same one. Or, as you noticed they could also be explained using two different types of C major modes.

Which ones would they be and how would you figure it out?

Posted by: Ben Higgins Jun 23 2014, 08:24 PM

Oh yes, the confusing "modes seem have the same notes as another scale" revelation ! I remember being confused by this as I'm sure everybody else here does smile.gif

It all depends on the starting note aka the ROOT. And the ROOT will dictated by what chord is giving the main tonality of the progression.

Regards to Ken's question.. what you have to do is play those chords he's given you. Make sure you include the respective minor or major 3rds in each chord sound. Now starting with the 1st chord (Am) start trying scales over it and see which one encompasses all the notes of that chord without adding any others that don't gel. (In regards to the scale, the clue is usually in the chord name - and whether it is minor or major)

If you look at Ken's 1st progression, then you would play the chord of D next. Btw, if a chord is written with just the letter D (or whatever letter the chord is) and it doesn't have an 'm written after it, then that chord is a major chord.

So, if you think you've found a scale that works over the 1st Am chord, then try that same scale over the D chord. Be careful of the major 3rd of D (an F#). If that scale doesn't include the F# then that scale doesn't fit over D. Try another mode of A. It's trial and error and a process of elimination. After a while you will just start to see certain chord progressions and just know what scale or mode to play over them. Other times, if it's not obvious at first, you can sit down and go through the process I described and find what mode works over all the chords.

But always use the starting chord as your base, as that chord is usually giving the tonality to the progression.

I didn't really go into why modes look like other modes depending on where you start them but I might let someone else take that one, I'm tired from the thinking ! laugh.gif

Posted by: PosterBoy Jun 24 2014, 01:18 PM

QUOTE (Barthandelus @ Jun 23 2014, 07:29 AM) *
Hi guys,
I have been working on scale modes for the past couple of weeks and although i now know the shapes of the modes, im confused on how they are related. For example, lets say im playing a riff in C major, and putting a lead over the top. How can this have the same notes as A minor? They seem to both have no sharps or flats, and i would therefore assume the same key signature? huh.gif

Going on from that, how do we know what mode a solo would be in? A 4 bar lick in Phrygian would have the same notes as Mixolydian? Does it really make a difference at the end of the day?

I guess i am getting confused on the actual use of the different modes. Note for note, they seem to be the exact same. If i know the major scale for a given key, what use are the other modes? smile.gif

Thank for your help on guiding me on this interesting subject.



One thing that might be a sticking point for you, it was for me is the chord progression.

Many/Most mainstream pop and rock song chord progressions aren't going to let you explore modes very much, You will just be using your major scale (Ionian mode) or Natural Minor scale (Aeolian Mode)

Your confusion between major and minor scale having the same notes is really what modes are all about.
Look at the interval gap of the C Major Scale
C Whole Tone D Whole Tone E Half Tone F Whole Tone G Whole Tone A Whole Tone B Half Tone C

Now A Minor (same notes)
A Whole Tone B Half Tone C Whole Tone D Whole Tone E Half Tone F Whole Tone G Whole Tone A

The intervals give the quality of the scale, You have a minor 3rd in the scale which give the dark or sad sound. So if you play the Aminor scale it sounds different to the C Major scale because of the intervals.

In a solo you aren't going up and down the scale all the time, so in this case using the A as a root or home note as will hitting the important intervals for that mode

I'll paste this from The Professor

QUOTE
Ionian - 4
Dorian - 6
Phrygian - b2
Lydian - #4
Mixolydian - b7
Aeolian - b6
Locrian - b5

Those are the characteristic notes of each mode.



Now back to chord Progressions.

If you listen to someone like Satriani, his modal instrumentals are generally over 2 or one chord vamps




The majority of that song is a constant C bass note with a D major to a C major chord, that sticks in you head, So looking at that how which mode would you play over? C Lydian

Why? because it is only mode with a C major chord and a D major chord in it with C as the Root (the constant bass note makes C the root or home note of the song)

Why not G Major or G Ionian or E minor (E Aeolian), try playing it over the track and using G or E as your home note, it just doesn't sound right.

I hope that helps

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