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So a minor seventh 'chord' is defined as being:

1, b3, 5, b7

But the natural minor 'scale' is said to have the degrees:

1 2 b3 4 5 b6 b7

Why is the 6th marked as being flat?

I guess I just don't understand that part of the music theory yet. Could maybe someone explain it for me?

To expand on my lack of understanding...

I can see, for example, the Phrygian mode has the intervals H, W, W, W, H, W, W, but in another question I asked there was a reply that mentioned "Phrygian Dominant Mode" and I'm not sure how that applies to a scale interval.

I know a dominant chord is defined by a 1, 3, 5, b7 so how do I apply that chord construction thinking to a scale?

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    I think you want to apply scale construction theory to chords. Think about this for a moment: Why wouldn't the 6th scale degree in a minor scale be flat? Why are you expecting it to be natural? "Minor" is just a name for a scale. Another name for the same scale is "Aolian". It's W H W W H W W. Notice the second H is between the 5th and 6th degrees. So that's why the 6th is lowered compared to the major scale. The chord comes from the scale (mostly), not the other way around. – Todd Wilcox Jan 23 '17 at 14:28
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Why is the 6th marked as being flat?

That's just the natural minor (=aeolian) scale: 1-2-b3-4-5-b6-b7 scale. If you want a similar scale with a natural 6th - 1-2-b3-4-5-6-b7 - that's the dorian scale.

It's very important to note that scales don't describe any natural phenomenon but are just human invention - you can make up any scale that you want, and even simply ignore the concept of scales, and it won't make a difference.

how do I apply that chord construction thinking to a scale?

So instead of writing the major (=ionian) scale as 1-2-3-4-5-6-7, we are going to write it as 1-3-5-7-9-11-13 (chord form, where 9=2, 11=4 and 13=6). This gives us a major 7th chord (1-3-5-7) with a natural 9th, a natural 11th and a natural 13th. So instead of this long 1-2-3-4-5-6-7, we could write it as Maj7(9,11,13) - which is how you write chords and their extensions.

Regarding the Phrygian Dominant scale which is 1-b2-3-4-5-b6-b7, we can see that it's a dominant seventh chord (1-3-5-b7) with a b9, nat11 and b13, and thus is written as 7(b9,11,b13).

Hope this helped!

  • I am also very against the thought of thinking about scales as patterns of H/W/WH as this doesn't tell you what the scale sounds like. Instead, writing the scale/chord degrees tells you what it sounds like. The only reason to look at the intervals in a scale is when constructing it (if you're using intervals instead of scale degrees) and when searching for its modes. – dudwhuknowstheory Jan 23 '17 at 14:57
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Natural minor is directly related to its relative major, using exactly the same notes. So, Cm, natural, will have 3 flats - Bb, Eb and Ab. If you like, start at the 6th note in the major scale, and count on 6,7,(8)/1,2,3,4,5 to find the natural minor notes.

The ordinary dominant chord can be seen in a different way - use 5,7,9,11 of the original key scale notes. As in C, they're G,B,D,F. That's actually the dominant chord in C. If you're thinking it's C,E,G,Bb, that's the dominant chord in F. Maybe not the dominant chord on F, though, 'cos that'll be F,A,C,Eb. Taking us into Bb... See where we're going?

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how do I apply that chord construction thinking to a scale?

If you describe a scale as a series of internals (half steps and whole steps) like your phrygian scale, here in two octaves...

H, W, W, W, H, W, W | H, W, W, W, H, W, W

...it might be helpful to also think of chords as a series of intervals. So a dominant seventh chord would be...

M3 m3 m3

...where M3 is a major third and m3 is a minor third.

Keep in mind M3 = W + W and m3 = W + H or H + W. So, the dominant seventh will be this sequence from the scale (W,W)(H,W)(W,H.) This only happens in one place in the phrygian scale starting on the third note.

Maybe this helps show the connection between scale and chords.

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Are you trying to ask why the minor seventh chord is described like that in correlation to your follow up why natural minor has b6 question or are those two different questions? A scale and a chord are two different things. The minor seventh chord 1, b3, 5, b7 is based on being part of the Major scale's dominant chord (5TH degree) in the Cmajor scale the 5th regular triad chord is Gmaj if you extend it to a 7th chord it becomeds a Gdom7 its noted as you described (1, b3, 5, b7) when speaking in theory/piano language. A minor scale can be noted as 1 2 b3 4 5 b6 b7 because it's being compared to the major scale. On a major scale if you flatten the 3rd, 6th and 7th degree it becomes a natural minor under the same tonality.

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