Modal and Altered Scale Tips

This is an on-going notes I am taking each time I come back to this topic. Originally published on October 12, 2012.

The 10 Modal Scales

Most textbooks write them in all sorts of different ways on the notation staff. For example, starting C with Ionian then move up one to D and Dorian. Some start with C with bunch of flats and sharps.

But instead of thinking about every note in respective scale, it may be easier to remember which notes are altered from the "standard major" or Ionian scale to me. Since I found out about that I usually relate to the chords, like b7 or minor 7 flat 5.

I personally dislike I, II, III notation of scales, I tend to think CDEFGABC, so when I am thinking in terms of Ab in key of Eb then I would think in my head "The Ab is the F to the C scale." Kind of convoluted, but it works for me.

By the way, if you are new to Greek Numerals. You need to know the following simple rules.

• I, II, III, V: 1, 2 and 3 and 5 from there you create other numbers.
• IV: to mean take 1 from V (5) which makes 4
• VI: now I is on the right so that means add 1 to V making 6
• VII: and that's 7.

X is 10. So now you know how to make IX (9) and X (11) and so forth but that usually do not come up in music.

At any rate, have no fear with 9th, 11th and 13th notes.  Just subtract 7 from these numbers but think of playing one octave higher. In the C scale that's just D, F, and A. So b9, #11, b13 as you will see in the altered scale means simply Db, F# (or Gb), Ab in the chord scale with the key of C.

Also note that the use of b5 is often not correct in theory on scales where you'd skip 4th but hit #4 and also include the 5th. That is the case for Symmetrical Diminished. Speaking of which, it is totally legit to play the 5th on the altered scale though they are often not included in the text books.

Apparently that's to avoid confusion with introducing chromatic scales (the scale in which the note goes up half step from the start to end.)

Below scales are introduced in the order of "Brightest Sounding to Darkest" in general.

There Are Only Two Major Scales - Lydian and Ionian

Lydian = #4
Ionian = "the standard diatonic major scale" in the case of C that's all the white keys.

Then Two Dominant Scales

Two are in Dominant (though there will be altered ones). This means that when a dominant chord is indicated there is a chance to substitute scales (if that sounds good).

Mixolydian = b7 (the regular major 7th chord). When a plain 6th is indicated in the chord like C6, then it is actually this scale.

Lydian b7 = #4 [or b5], b7 (not usually included in the textbook modal scales).

Note that in Jazz and popular music the b5 is notated more commonly than #4, but theoretically it is more correct to say #4 here because V (5th) is in the scale but the 4th is altered.

The Rest are Minor Scales

Dorian = b3, b7 (the regular minor 7th chord). Also when m6 is indicated in the chord use this scale. Blues players take note on this scale. If the chord symbol indicates m7 and m6 this is the common scale.

Aeolian = b3, b6 or (#5), b7 is also called a Natural Minor Scale

Phrygian = b3, b7, b9, b13 (though actually b2, b3, b6 and b7) Noted Sus4(b9)

Locrian = b3, b5, b7, b9, b13 (though actually b2, b3, b5, b6, b7)  If the chord symbol indicates (m7b5) this is the scale.

Also, not a part of modal stuff, but worth a note:

Melodic Minor = 7th is not flat. (i.e. often notated as minor major 7). Note also that this is usually used on ascending melody or solo direction only in Jazz. Compare this with Natural Minor which is Aeolian.

Then Comes Altered Scales

Altered = b7, b9, #9, #11, b13. The 5th is actually OK to play though not in the text book. Another interesting fact on this is that if you raise the half step and play a melodic minor on that scale then you get the ALT scale. So if you see C(Alt) then play the C#m. Or another way to look at it is on and after #4, it is the whole tone scale (thought the 5th is actually permitted.)

Symmetrical Diminished = #4, b7, b9 #9, natural 13, b7 (b2, b3, #4, 6, b7).  5th and 6th are included in the scale!

Both in Sym-Dim and ALT scales b9 and #9 are always in both but on ALT scale b5, b6 are present.

Since in both cases if you see a b9 then it is almost always correct to assume a #9 in the scale.

Important Distinction! If the 6th (or the 13th) is not flat then it is the Symmetrical Diminished. ALT has a flat 13.

So the trick is this. If I see a b9, then I will have to check if 13th is a b13. If it is b13 then it's altered and if natural 13 then it is potentially a Symmetrical Diminished. For example, in the key of C, I would look for Db then if Ab is present then that's likely an ALT otherwise it can be a symmetrical diminished.

When the scale starts "half-full-half-full-half-full-half" scale then that's the Symmetrical Diminished scale. And noted like C7b9 whereas DIM scale which is often written with a ø like Fø is the same as Sim-Dim with one difference, it starts with Full-Half-Full-Half steps.

Dominant Substitution

There are many chords that can be substituted when a dominant 7 (like G7) is indicated in the chart.
Use of the altered scale is a very likely candidate.

Another one that I like is the Tritone Substitution which is to use the dominant chord above 5 step and back down half step (easier than saying 6 half step up). So in the Dm to G7 to C progression, plus 5 of a G is D and half step is Db, which turns out to be a half step above the last chord of C.

In reality you see a lot of situations on Jazz where usually the last dominant chord is approached from a chord half step above, then that's what they are doing.

Scale Selection Hints

So which scale to play? This has been the major mystery to me for the longest time but I was explained basically the following and that makes complete sense to me.

• Look at the Chord Symbol. This gives the basic framework of the scale. For example Cmaj7 would one of two major scales. If it's minor chord then look for one of the modal scales.
• Then use the following ideas to seek notes that will be included in the scale.
• Look for the hint notes in the current measure's melody line.
• Look for the hint notes in the preceding measure. If this is the first measure then the preceding measure is the last measure in the song (makes sense.)
• Usually the last Dominant 7th chord of a song section (like at the 8th measure) is ALTerable.

Hearing the Sound on Keyboards.

• On your left hand play only the root, 3 and 7 or root 7 and 3.
• On your right hand play the whole scale or extensions like b9 etc or melodies including these notes.