How To Determine The Key Of A Melody - Part 4 - ZERMELO

How To Determine The Key Of A Melody – Part 4

So far, we've only looked at the minor scale.

Yes, we've looked at:

  • Scale Formulas
  • Scale Degree Names
  • Intervals
  • Melodic Contours
  • Chord Construction

But, we've only looked at these topics using the minor scale.

But this was strategic.

Remember, in house music, the most common scale is the minor scale.

So we used the minor scale to (1) introduce you to the “key-finding” techniques and (2) cover the most ground for you if you wanted to try to start figuring out melodies right away.

If you've internalized the techniques we've covered so far — and understand how to USE them — then the next part of this series will be easy.

We're going to look at how to use these techniques — to determine the key of a melody — with other scales. Scales such as:

  • Major Scale
  • Phrygian Mode
  • Dorian Mode
  • Harmonic Minor Scale

But before we start, we need to learn something new.

And here it is:

The BEST way to understand scales (in general) is see how they differ from the major scale.

This is important so I'll say it again in a slightly different way:

We need to understand how to DEFINE other scales in terms of the major scale.

To unpack this idea, we need to go through two big steps:

Big Step #1 – Let's look at the major scale in the same way we looked at the minor scale:

  • Major Scale Formula
  • Scale Degree Names
  • Major Scale Intervals

Don't worry, we'll be quick here.

Big Step #2 – Then we'll define the other scales in terms of the major scale — including the minor scale.

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Big Step #1 – The Major Scale

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Major Scale Formula

The Major Scale Formula is:

W W H W W W H

Let's run through an example and use the Major Scale Formula to derive all the notes in the C major scale.

Starting with C…

  • Go up a whole step from C to D
  • Go up a whole step from D to E
  • Go up a half step from E to F
  • Go up a whole step from F to G
  • Go up a whole step from G to A
  • Go up a whole step from A to B
  • Go up a half step from B back to C.

So we get: C, D, E, F, G, A and B.

That's it!

From now on, no matter what note you start on, you can figure out the notes of the major scale using that starting note as the tonic.

Scale Degree Names Of The Major Scale

Speaking of tonic, let's look at the scale degree names of the major scale.

Are they different than the scale degree names of the minor scale?

Remember the scale degree names of the minor scale:

  • Tonic
  • Supertonic
  • Mediant
  • Subdominant
  • Dominant
  • Submediant
  • Subtonic

The scale degree names of the major scale are:

  • Tonic
  • Supertonic
  • Mediant
  • Subdominant
  • Dominant
  • Submediant
  • Leading tone

So there's one difference — the seventh scale degree.

In the minor scale, the seventh scale degree is called the “subtonic” and it's a whole step down from the tonic.

In the major scale, the seventh scale degree is called the “leading tone” and it is one half step down from the tonic.

This is a SUPER important difference…

Because almost ALL Western Music Theory boils down to (1) the leading tone and (2) its role in something called “dominant function.”

But we don't need to know about this at all to figure out what key a melody is in, so we'll skip it.

Instead, let's move onto the intervals of the major scale. But first, let's run through a quick example of the scale degree names using C major.

  • 1 = C = tonic
  • 2 = D = supertonic
  • 3 = E = mediant
  • 4 = F = subdominant
  • 5 = G = dominant
  • 6 = A = submediant
  • 7 = B = leading tone

These scale degree names hold for the notes in any major scale.

Intervals Of The Major Scale.

When we looked at the minor scale, we made a big chart. So let's make the same chart for the major scale:

  • 1 to 2 = tonic to supertonic = major second = +2 half steps
  • 1 to 3 = tonic to mediant = major third = +4 half steps
  • 1 to 4 = tonic to subdominant = perfect fourth = +5 half steps
  • 1 to 5 = tonic to dominant = perfect fifth = +7 half steps
  • 1 to 6 = tonic to submediant = major sixth = +9 half steps
  • 1 to 7 = tonic to leading tone = major seventh = +11 half steps
  • 1 to 8 = tonic to tonic = octave = +12 half steps

Did you notice the changes?

There's only three differing notes: scale degrees 3, 6 and 7.

(This is SUPER important.)

In the minor scale, there is a minor third interval (+3) between the tonic and mediant. But in the major scale, there is a major third interval (+4).

In the minor scale, there is a minor sixth interval (+8) between the tonic and submediant. But in the major scale, there is a major sixth interval (+9).

In the minor scale, there is a minor seventh intervals (+10) between the tonic and subtonic. But in the major scale, there is a major seventh interval (+11) between the tonic and leading tone.

Again, there are only 3 differences. And this is the BIG PIECE we need to move onto Big Step #2…

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Big Step #2 – Defining Scales

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How To Define Scales In Terms Of The Major Scale

Let's define the major scale using simple numbers:

1 2 3 4 5 6 7

And as we saw, the minor scale has only 3 different notes:

Scale degrees 3, 6 and 7.

But how are they different?

In the minor scale, scale degree 3, 6 and 7 are a HALF STEP lower than scale degrees 3, 6 and 7 in the major scale.

Because of this, we can define the minor scale in how it differs from the major scale, like this:

1 2 b3 4 5 b6 b7

See?

To define a scale, all we have to do is note HOW said scale differs from the major scale.

For example…

If a melody has the notes C and A, then you know it can't be in the C minor scale because C to A is a major 6th interval.

But if you saw C to Ab, then you know the melody could be in C minor because C to Ab is a minor 6th interval.

So (1) knowing how to figure out the notes in a scale and (2) understanding how the notes in a scale relate to each other is all you need to figure out what key a melody is in.

Other Common Scales.

Here are some other scales you'll likely encounter:

  • Major Scale: 1 2 3 4 5 6 7
  • Major Scale Formula: W W H W W W H
  • Minor Scale: 1 2 b3 4 5 b6 b7
  • Minor Scale Formula: W H W W H W W
  • Phrygian Mode: 1 b2 b3 4 5 b6 b7
  • Phrygian Mode Formula: H W W W H W W
  • Dorian Mode: 1 2 b3 4 5 6 b7
  • Dorian Mode Formula: W H W W W H W
  • Harmonic Minor: 1 2 b3 4 5 b6 7
  • Harmonic Minor Formula: W H W W H W+H H

The minor scale will cover 80-90% of the cases. And these other scales will take care of the rest.

Do you see how these work?

Let's take a look at the Phrygian Mode. Fancy name, just another scale.

You can see that it has 4 notes that differ from the major scale: scale degrees 2, 3, 6 and 7. All of them are flattened relative to the same degrees in the major scale.

Also, notice that the Phrygian mode only has a flattened 2nd relative to the minor scale.

The Dorian mode (again, fancy name, just another scale) has a “natural” 6th relative to the minor scale. And a natural 6th is simply one that is shared with the major scale — it's not flat or sharp.

So you can see that while the minor scale differs from the major scale by 3 notes, the Dorian mode differs from the major scale by only 2 notes. This natural 6th gives the dorian mode a sad, but “hopeful” feeling.

Finally, you can see something funky going on in the Harmonic minor scale. There is a “W+H” interval in the scale formula. This is just an interval that is a whole step plus a half step. This interval is also called an “augmented” second — which means it's a half step bigger than a major second.

Two more observations:

(1) House music is mostly minor.

4 out of the 5 scales here are minor scales and modes — meaning the 3rd scale degree is flattened.

(2) Where are the half steps?

In Part 3, I told you that scales differ based on where the half-step relationships are.

So look at the scale formulas above — and notice how the half-step placements are all different.

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You've Got It All.

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Now, you have all the pieces:

  • Minor Scale Formula
  • Scale Degree Names
  • Scale Degree Intervals
  • Melodic Shapes
  • Tonic Chord Tones
  • Half-Step Interval

And the final piece:

You know how to apply these principles across the spectrum of scales.

So no matter what melody you come across, you can identify what's going on in the melody. You can dissect the intervals inside the melody. And you can figure out what key the melody is in.

Good luck!

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