21st February 2012
Lives for gear
Some people also use it to describe music with static harmony using the same notes as a mode of some popular scale, like many examples of Indian music that has droning notes and a melody and improvisation using the same intervals (or close microtonal variants) as mixolydian.
I woulld stop short of calling that objectively wrong, but to me that's misleading because that scale in that culture is, as far as we know, not a derivative of major scales like it is for us... it really is a home scale that implies no other tonality, nor relies on other tonalities for notes or theoretical ideas, in that music.
Key is really about resolution, that's the primary purpose and meaning of it. In diatonic music it also provides simple ways to know what the "good" notes are... and we extend that habit outside of diatonic music, which is where we get into trouble.
If I am talking about key in a non diatonic song, I am talking about the tonal center. It doesn't really work to say the key is one thing and the tonal center another. If it doesn't resolve to that root, it's not in that key.
You can absolutely play an F lydian scale over a diatonic C tonality. Play a CM7 and run up and down an F lydian scale as the chord still sounds. Done.
Scales can be linear melodic material. F lydian as a linear searies of notes doesn't cease to be F lydian as the context changes... although the resulting tonality of the piece as a whole certainly changes as different sets of notes are played together.
In that example, what defines that set of notes as F lydian as opposed to C ionian ? Just the order and emphasis, and this is really about the melodic line. It is possible to "play" different diatonic modes of the key with a certain amount of clarity, it just takes frequent emphasis of the changing starting notes.
This is what we are doing when we play through the changes of a diatonic song, by favoring chord tones. Sure, all those notes are in the original parent scale... but you can, nonetheless, make the changes.
Doing that over changing diatonic chords should be familiar to any competent player. Doing that while changing modes when the underlying chord does not change, is one other possible meaning of modal music that we haven't previously touched on. You could call that superimposing diatonic chords; it's like a non aggressive way of being harmonically aggressive.