Let's say I am in the key of C and trying to write a simple melody over some chords on the piano.

Chord progression: I (Cmaj) IV (Fmaj) V (Gmaj) I (Cmaj)

Let's take the IV chord for instance. What's the difference between connecting the IV chord to the Lydian mode so I can use the pitches in F Lydian mode to create a melody versus just using the pitches in the key of C itself? Won't I be using the same pitches/notes anyways?

Is it not easier to just focus on the keys pitches during the progression to create a melody rather then having to think about each mode for each chord?

3 Answers 3


It sound like you may be mixing up "classical" versus "jazz" or "pop" approaches to harmony and melody.

I'm using "classical" in very broad sense to mean something like Western tonal harmony.

...connecting chords to modes...

Matching scales and modes to chords is a typical jazz/pop approach.

...using the pitches in the key of C...

Classical style doesn't match scales to chords, but rather works with the tones of the key.

You already point out that the tones of the modes are the tones of a key (when the progression is diatonic.) In fact there is a lot of overlap between these two approaches to harmony and melody.

At this point it's probably best to figure out what style you are working in and approach your work within that frame work. Of course you could be working in a style that mixes styles or is totally eclectic in which case we cannot have a "black or white" answer.

Your wording...

...writing in an established key... ...over some chords...

...makes me believe that your working in a "classical" and homophonic style.

A very common approach in homophonic style is to write the melody using the chord tones of the given progression. (There is a theoretical argument about whether melody is generated from chords or vise versa, but let's skip that.) Such chord derived melodies can be decorated with various non-chord tones both diatonic and chromatic.

  • "Classical style doesn't match scales to chords, but rather works with the tones of the key." This isn't true on either front. Firstly the jazz approach used by players up to and including the 70s was very similar to how one would improvise classically (albeit with an often different tonal vocabulary). Until the chord-scale system started being taught as the underpinning for jazz improvisation, jazz players looked at harmony much more like a classical composer might; you look at the pitch centre, the harmonic progression, the melody for its own sake, and you try and come up with something.
    – Some_Guy
    Nov 28, 2018 at 17:41
  • Secondly, this idea that classical harmony only cares about the tones of the key is not right either: classical harmony absolutely follows chords, it might not analyse it in the reductive way the chord scale system does, and it might not use the same nomenclature as jazz, but listen to Tchaikovsky, Chopin, Liszt, Ravel, Fauré... and you'll find they very much "follow the changes" as a jazzer would put it. And they also more and more as the years roll on start using notes "just for colour" too, as jazzers do. It's not a coincidence either, a lot of cross-fertilisation has gone on.
    – Some_Guy
    Nov 28, 2018 at 17:47
  • This isn't meant to be one of those "jazz basically gets all of its good stuff from classical" comments, I'm not saying that at all, far from it. And I'm not a classical player, I'm really a jazz guy. But when you listen to classical music, especially from the romantic period, a lot of it absolutely sounds like a melody with changes. And not all of the same ways of moving through changes are used, of course not, as a jazzer you could literally write a lead sheet for a lot of it and it'd make perfect sense. youtu.be/YR5USHu6D6U youtu.be/KpOtuoHL45Y youtu.be/9E6b3swbnWg
    – Some_Guy
    Nov 28, 2018 at 18:07
  • I think you missed my comment... "there is a lot of overlap between these two approaches." Also, I think you misread some of my answer. I didn't say all jazz exclusively matches modes to chords. I said it is typical to jazz not to classical. Also, your wording '...only cares about the tones of the key" is not what I wrote. I think you must mean only the diatonic tones of the key, which is also not what I wrote. In fact I wrote that the melody can be decorated with tones both diatonic and chromatic. Nov 28, 2018 at 18:07
  • My answer was mainly to confirm the OP's observation about two general approaches without making exclusive, misleading, or plainly false statements. Covering all the overlapping details and history of western music is beyond the scope of a Q/A forum. Nov 28, 2018 at 18:16

Yes, in your example it is absolutely overkill to think in terms of all those modes. However, what you're seeing is an example of "chord scale theory" and it's pretty central to jazz harmony. What you're seeing is just the simplest version of the central idea, which is:

Every chord should have a scale associated with it.

If you're staying strictly diatonic, you're just going to get the ioanian, the dorian, the phrygian, etc, which is just the major scale. But what if you got an E7, for example? It's probably resolving towards Am7, in which case it should take a mixolydian flat 13, flat 9, which is the go-to scale when resolving to a minor.

Another example might be Ebmaj7, which should take lydian, since it's a borrowed major chord from C minor and those will always take the lydian (we're still technically in C major, but this chord just popped up all the same).

There are a bunch of rules like that and you also have a lot of freedom of choosing other scales than the most standard ones. But at its heart, chord scale theory is meant to help you with tricky chords progressions.

  • I'm curious as to what the rationale behind your statement "E♭maj7 [...] should take lydian, since it's a borrowed major chord from C minor and those will always take the lydian". Are you simply observing this pattern, or claiming a theoretical explanation for this? Because if you have an explanation for why this is true, I'd like to hear it, if you don't mind.
    – user45266
    Nov 29, 2018 at 18:17
  • Actually it's just something I got taught when taking harmonic theory in school and I myself never got it fully explained. i think the reasoning is that the ionian is such a tonic-inducing scale that you are going to be in a new key if you're using it. I.e. the lydian allowes you to play over borrowed chords without really modulating. Does that make sense? Dec 2, 2018 at 2:29

If you're in the key of C major and thinking tonally, B natural will be an 'avoid' note over an F chord. You can use it - heck, you can use anything - but it's not going to be emphasised as a harmony note.

However, if you're thinking modally, the B natural may well be strongly featured over a F chord!

  • 1
    A song I guess you've played hundreds of times, Moon River, does pretty well that. Bar 3. B melody over an F chord. Maybe Hank thought modally?
    – Tim
    Nov 28, 2018 at 16:43
  • @Tim great example. I suppose that's the exception that proves the rule as the B avoid tone resolves into the A chord tone. Nov 28, 2018 at 18:35
  • Yes, styles and 'theories' mix. And I have to force myself not to substitute a juicy F7(#11) for the simple suspension EVERY time it occurs, save it up for the last one!
    – Laurence
    Nov 29, 2018 at 11:52

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