Does anyone have tips or tricks for remembering the function of mode harmony?

Question

When I mean by that, I understand how the 7 modes are constructed:

• Ionian: Major scale with no alterations
• Dorian: natural minor scale with 1 alteration: #6
• Phrygian: natural minor scale with 1 alteration: b2
• Lydian: Major scale with 1 alteration: #4
• Mixolydian: Major scale with 1 alteration: b7
• Aeolian: natural minor scale
• Locrian: natural minor scale with 2 alterations: b2, b5

Does anyone have tips or tricks for remembering the function of mode harmony?

My intention is to create chord progressions with Modal Interchange to create more color without any cheatsheet or just one-way Practice in 12 keys and remember day by day and stop using a cheatsheet — just use it for reference only and apply this concept as much as I can. Do you have any advice on this topic? or Would you share how you learn to pass through this obstacle?

Answer 1

TLDR; I don't think there is one. As others have already said, you can probably theoretically justify borrowing¹ just about any chord.

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Let's start by constructing a table of the modes and the 4 note chords that would be built from each scale degree. I'm using all caps roman numerals throughout, even though the case usually indicates chord quality, but it is much simpler if we just stick with the caps, and I didn't want to use numerals for the scale degree to help separate the scale degree from the chord qualities.

There are four types of chord: 7, -7, △ and the half diminished (-7b5 or ^ø7), and each of the twelve tones is used at least once as a chord root. I did this in Excel, which makes it really easy to generate another chart that will reduce this to a list of which chord types appear in the modes for each scale degree. Although the IV in Lydian is the #IV I am including only the enharmonic bV in this chart.

So, for I we encounter all four chord types, and for bII only the △, and so forth. I'm going to remove all of the non-scale tones (bII, bIII, etc) in a new chart, just to make it easier to point out something:

There are 28 combinations of scale degree and chord type, and about three quarters of them appear somewhere in a mode.

But notice that III⁷ doesn't appear in this chart. While I suppose it is technically true that E⁷ doesn't appear in any of the parallel modes in C^*, it is arguably one of the most famous borrowed chords of all time. It's also a very legit sub for V⁷.

There are some other noticeable exclusions. bII⁷ isn't represented in the chords borrowed from modes, but is a common sub for V⁷ (which is), as in ii⁷-bII⁷-I instead of ii⁷-V⁷-I. IV^ø7 isn't in this chart, but is both quite groovy and also a fine sub for bII⁷ (which also isn't) or ii^ø7 (which is), and I commonly use IV^ø7-V⁷ as a more harmonically complex (and pleasing to me) alternative to V⁷sus-V⁷-I.

VII⁷ doesn't appear, and how many times have you heard B⁷-Em in key of C? III^△ doesn't show up, but I'm pretty sure I could make that work (depending on context) for C+ or Cm/maj7.

I guess what I'm getting at is that if you are only looking at modes for borrowed chords, you're leaving out some other substitutions that are very common (probably more important than anything you'll get at this way), and if you start including chords that are borrowed with other methods, then you get into a situation where you can theoretically justify any chord whatsoever, and the more you do that, the more you reduce the utility of the cheat sheet (or mnemonic technique, or rule, or whatever you are creating).

And that's the thing. You can try out a chord indicated to you by some theoretical method, but they are all context dependent, some to a greater degree than others, and the theory of how they work isn't necessarily that indicative of whether or not you can pull them off in a practical setting, so there's really not that much point in trying to memorize all the possible permutations. A cheat sheet or such might not be feasible for practical application, especially if you expand it to cover all possibilities, but it is just fine for practice sessions, which is where you'll mostly be working through these ideas, anyway.

All that being said, here is a list of all of the chords used by scale degree in all of the modes. Whether or not you can pull off something like #IV^ø7 in place of the four chord³ is going to be up to your ears:

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¹ "borrowed" refers only to chords that appear in a parallel mode, if I remember correctly from my theory days. However, it seems to me that the term is used much more loosely in practice, for instance V/V relationships or in other cases where you appropriated a chord from a more (or less) related key

^* I'm not sure if the source is V/vi or the V from the harmonic minor, or if this is even a settled question, or matters. Theory is kind of made up after the fact to explain things that were already happening

³ The two chords are almost identical: F-A-C-E vs F#-A-C-E. But if you were to substitute that into a I-IV-V in C, would the ear interpret that as an alteration of IV or as a V/V (C-D⁷-G⁷)? Same question if you borrow the II⁷ from Lydian. Will the ear interpret this as an altered II, or hear the V/V relationship, or some other possibility? It is all highly contextual.

Answer 2

Not certain where you're going, but...

I tend to think of modes as changes in/ adaptions of the parent key.

In other words, C Ionian has no change.

D Dorian uses all the notes/chords from C.

E Phrygian uses all the notes/chords from C.

F Lydian uses all the notes/chords from C.

G Mixolydian uses all the nots/chords from C.

A Aeolian uses all the notes/chords from C.

B Locrian - you have the idea, but Locrian is strange!

So I go back to the parent key, knowing the notes/chords from that key.

Other example. D Mixolydian: parent G major. Giving the chords G, Am, Bm, C, D, Em, F♯o.

Seems easier, as we probably would have learnt the 'chord families' before we tackled modes.

Answer 3

One simple "trick" is to make use of the order of the modes.

0. Ionian/Major
1. Dorian
2. Phrygian
3. Lydian
4. Mixolydian
5. Aeolian/Minor
6. Locrian

A consequence of the ordering is that the i chord in Dorian is that ii chord in Major, for example. That is, when thinking in Dorian, subtracting 1 will give the Roman numeral in the relative Major.¹ Similarly, in Phrygian, subtracting 2 will given the Roman numeral in the relative Major, and subtracting 1 will give the Roman numeral in the relative Dorian.

Suppose we're composing in Mode A and want to know how the current chord corresponds to relative Mode B. We can use the following formula:

Mode B Roman numeral = (Mode A Roman numeral - (Mode B number - Mode A number)_{Mod 7})_{Mod 7}

Examples

Example 1. Given the six chord in Mixolydian, what is the corresponding Roman numeral in Dorian?

• Mixolydian = Mode A = Mode 4
• Dorian = Mode B = Mode 1
• (1 - 4)_{Mod 7} = 4
• six - four = two

Thus, the two chord of Dorian corresponds to the six chord of Mixolydian.

Example 2. How does the Lydian four chord correspond to the Locrian mode?

• Lydian = Mode 3
• Locrian = Mode 6
• (6 - 3)_{Mod 7} = 3
• four - three = one

Thus, the four chord in Lydian corresponds to the one chord in Locrian.

Example 3. I'm currently in Phrygian and want to get to the four chord in Ionian. Which is the corresponding Phrygian chord?

• Four = (X - (0 - 2)_{Mod 7})_{Mod 7}
• Four = (X - -2_{Mod 7}) = (X - 5)_{Mod 7}
• X_{Mod 7} = 9_{Mod 7} = Two

So the Ionian Four chord corresponds to the Phrygian Two chord.

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¹ _{I am careful to refer to "Roman numeral" rather than "chord function", because functional harmony is defined only in terms of major and minor. Modal harmony pointedly avoids the strictures of functional harmony, so Roman numerals are convenient labels, but do not denote chord function.}

Answer 4

You have my permission to chromatically modify any chord in your song. You could almost certainly justify this as 'modal interchange'. The modified chord probably exists in SOME mode. Does it matter which one?

But if you want to label your alterations, I suggest you memorise and internalise the list of alterations stated in your question.

Answer 5

The Father Christmas Brought Dad An Electric Blanket counterpart for modes is

I Don't Punch Like Muhammad ALi

This should help you remember the modes in order.

Answer 6

The traditional Ionian → Dorian → Phrygian → Lydian → Mixolydian → Aeolian → Locrian ordering is good for deriving the diatonic modes associated with one key signature.

To work out the alterations needed for the various modes in one tonic, I prefer to think of them in a "circle of modes" organized by the number of sharps and flats in the key signature.

It should help you remember the alterations and possibly help with "smoother" introduction of modal alterations.

Examples:

• The key signature for B Ionian (major) has five sharps. To get to B Phrygian, we go 4 degrees flatter (remove 4 ♯s, ending with one ♯). You could also reach Phrygian by going 3 degrees sharper, but that ends up with 8 ♯s (i.e. F𝄪), and raises the tonic to B♯

• The key signature for C Aeolian has three flats (same as E♭ major). To get to C Lydian, we go 4 degrees sharper (remove 3 ♭s, add one ♯). We add and remove them in the normal order. You could also reach Lydian going the other way and make it 3 degrees flatter (add 3 ♭s) but that ends up adding a C♭ (which changes the tonic).

• The key signature for A Mixolydian has two sharps (same as D major). To get to D Locrian, we go 4 degrees flatter (remove 2 ♯s, add two ♭s). If we go the other way, we add up with 5 flats, including a D♭.

How do you know which way to go around the circle to avoid altering the tonic? I chose to put Dorian at the top, because if you start at Dorian in any key, you can reach any of the other modes by the shortest distance without altering the tonic (though you may end up with an ungodly number of sharps or flats in the signature). If you start elsewhere, you should move in the direction of Dorian (and past it if needed) to avoid altering the tonic.