I'm very confused when choosing modes to solo over my chord progressions. I've read that the Lydian scale is often used over underlying Major or Major 7th chords, to cut down on the natural clashing between the (M3) & (P4) degrees that lie a half-step apart.

So, my understanding is that when soloing over a (CMaj7) chord in this example, that choosing (C Lydian) would be best.

But, my confusion lies in the fact that now, the (#4) creates just as much clashing with the 5th scale degree chord tone, as the (4) would have over the (3).

CMaj7: (C - E - G - B)

C Ionian: (C - D - E - F - G - A - B)-> (F) in the solo clashes with chord tone (E)

C Lydian: (C - D - E - F# - G - A - B)-> (F#) in the solo clashes with chord tone (G)??

How does choosing Lydian help at all? Do chords that have Lydian playing over the top of them not include the (5) or something?

  • "I've read that the Lydian scale is often used over underlying Major or Major 7th chords": where did you read this? What kind of music were you reading about?
    – phoog
    Sep 7, 2022 at 4:48
  • It's clear to me you're asking about jazz harmony, but I agree with phoog, knowing your source for this info could be helpful. Chromatic Lydian Concept? Sep 7, 2022 at 12:48

4 Answers 4


The main reason for choosing the Lydian over the Ionian mode when soloing is if you want to use the 4th degree of the Lydian scale as a target note. There is absolutely nothing wrong with soloing using the Ionian mode over major, maj6 and maj7 chords, especially if they are the tonic chord. The important thing to be aware of is that in Ionian the 4th degree should be used as a passing note, not as a target note.

The natural 4 note will clash against the 3rd degree for sure because it will likely produce a m9 interval between melody and harmony. However the #4 will not create that same clash with the 5th because it will generally be above the 5th, producing a M7 interval.

Both scales are useful for improvising. As a soloist you make the choice of which scale you feel is more appropriate and fitting based on your personal taste and what you feel works best with the music.

  • Does ^4 mean the raised fourth? The convention here seems to be to use ^4 for 4 with a circumflex above it, which is difficult to achieve on this site, and which means "the fourth scale degree of whatever scale you're using." So it's a bit confusing here because it's hard to tell when you mean the fourth degree of the lydian scale and when you mean the fourth degree of the major scale.
    – phoog
    Sep 7, 2022 at 10:59
  • @phoog the convention I see on this site is placing a hat in front of the digit, as there's no easy way to place it above. I agree it would be great to have such possibility, perhaps via MathJax, but a better place to request that is the meta forum. Sep 7, 2022 at 15:41
  • @user1079505 I'm not requesting functionality. I'm suggesting an improvement to this answer.
    – phoog
    Sep 7, 2022 at 16:13
  • @phoog I’ve seen ^4 to indicate the 4th degree of the scale many times on this site so that’s what I meant. I thought it was somewhat universal by now but I will remove it as I don’t care for it myself much anyway. Sep 7, 2022 at 17:08
  • @JohnBelzaguy I only found it confusing because it didn't seem to say which scale's 4th degree it indicated.
    – phoog
    Sep 8, 2022 at 8:32

The clash between 3 and 4 is generally perceived as harsher than the clash between the clash between #4 and 5.

The reason for this perception is speculation, as best, but three reasonable possibilities:

  1. 3 plays a much stronger role than 5, which is often omitted altogether, in defining the sound of major seventh and dominant seventh chords, producing a stronger clash.
  2. #4 is easily perceived as b5, which is a widely understood "blue note".
  3. The "real" problem is the tritone between 4 and 7. 4, 5, and 7 are the characteristic tones of the dominant chord, so it's as though the major and dominant chords are being played at the same time.
  • Regarding your point 3: P4 is a very similarly clashing tone over a dominant seventh chord as well despite they don't introduce a tritone. Sep 7, 2022 at 15:35
  • @user1079505 That's true, but the tritone in that case does not occur in the presence of the quality-defining tone of the major tonic chord. In the major seventh case, the entire tonic chord and the main three tones of the dominant chord are all present.
    – Aaron
    Sep 7, 2022 at 15:45

natural clashing between the (M3) & (P4) degrees that lie a half-step apart

I don't like this explanation. To me a better description of the "issue" with P4 over a major chord is that it creates harmonic ambiguity. C major with added F sounds like some voicing of the F chord. It's important to notice that the F chord is a subdominant in they key of C, thus is a significantly different function, creating different tension.

No (or much less of) such ambiguity is created if you play F# over C major.

  • I don't disagree about the perfect fourth, but I think more explanation is needed, because the same P4 sounds great in a minor seventh chord.
    – Aaron
    Sep 7, 2022 at 4:47
  • I don't have an explanation, it's an observation. The point I'm making is that the interval of semitone is not causing a clash by itself, as a semitone between #4 and P5, or 7 and 8 doesn't cause a clash. Sep 7, 2022 at 15:34

Go back to an earlier philosophy of 'what to play over a chord'. (Not THAT different to the Berklee orthodoxy when you look carefully.)

Favour the notes of the triad. Tolerate other notes that aren't a semitone away from a triad. Avoid the notes that ARE. 'Blue' the 3rd, 5th and 7th freely.

So, if the chord is C major, favour C, E and G. Allow D and A. Avoid F and B. Pepper with E♭, G♭ and B♭ .

#4 has become very much the 'sound of modern jazz'. But you're right, it's pretty 'outside'. Perhaps the concept that there must be a 7-note scale that fits any chord is flawed, or at least not the ONLY approach to take?

Or you can cop-out completely and play a pentatonic scale!

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