First off, sorry if I used non diatonic wrongly in the title. I know that different modes are assigned to different degrees of a scale, like in a major scale I is Ionian, IV is Lydian, etc. Surprisingly, I only recently worked out that this is related to the key, like in the key of G, F isn't Locrian, F# is. But I was wondering then what would I use if I wanted to play a chord that didn't fit into the key. If I was playing in G, and suddenly had an overwhelming urge to play a bar of F using modes, how would I go about that?
I think what your talking about are key changes. This happens all the time. Listen to "So What" on Miles Davis's "Kind of Blue". 16 bars of D dorian followed by 8 bars of Eb dorian followed by another eight bars of D dorian. This kind of harmonic structure is what we call "modal" as opposed to "tonal" or "functional" harmony. That doesn't mean that you can't have chord changes like this in tonal music though!
I tend to use those things on the side of my head. NON DIATONIC chords generally come from either modal interchange or secondary dominance. Basically what you are doing is "implying" a transposition to a new key by using chords that function in that key. But again, you don't do that because of an "urge", you do that because that's what you're hearing. Like "I'm in G, what can I play so that it sounds like we're in Bb major?" Or more like "I want to modulate up a minor third, what gets me there?"
In addition, there's a sense in which modes can be independent of any conventional major or minor key. They can represent tonalities (or modalities), or tonal centers, all by themselves. Thus, sometimes when you're playing a few bars in F lydian, you're not necessarily "really" in the key of C playing the IV--you're really in F lydian, and that's the best way of describing what's happening. The "So What" example above is instructive. When you play that, the first 16 bars are definitely not in C major, even though D dorian is often spoken of as the second mode of C major. There's no functional C major harmony going on there, so it would be meaningless to try to relate those 16 bars to that key, in terms of harmonic understanding. You're "really" in D dorian, for all intents and purposes.
You would not play D Dorian mode over a C major chord anyway. You would use the D Dorian over a C-7 or C-9 chord, or something like that. But, it is still in the key of C.
D dorian is D E F G A B C D. You usually wouldn't play that over a C-7 or C-9. D-7 or D-9, more likely. (Insert usual disclaimers about anything being playable over anything if that's what you hear.) And no, D dorian is not *necessarily* "in" the key of C. It shares the same tones, and you can find it occurring within C, but that doesn't mean it has to be in that key. Again, D dorian can be its own tonality without any reference to the key of C at all.
Woah, I've just entered into another part of theory I didn't know much about (it always seems to do that. Just when you think you're getting the hang of it, BAM!). I think you've uncovered something that's been confusing me about modes. How can D Dorian have different tonality to C Major? I'm assuming here that you mean if you stuck more or less to the notes of the scale. They're the same notes, so how could one avoid refering to the other? I guess with D Dorian you would base it around D, and intervals would be relative to D, but they're still the same tones. I think my ear is letting me down at this point. I can't really detect a great deal of difference between the various modes, the only scale that I've so far noticed sounding unique is the harmonic minor.
Yes, you kind of have it. The same handful of tones will sound different when referenced to a tonal center of D or A than they do when everything centers harmonically on a tonal center of C. All a scale or a mode is is a set of tones at certain intervals from a specified starting point (which is presumed to be the tonal center, at least for the time being). For a major scale, for example, the pattern from the starting note is whole step-whole-half-whole-whole-whole-half. The pattern for dorian is whole-half-whole-whole-whole-half-whole. So even if the note names are the same, it's clear that the pitches stand in different relationships to their starting point. To hear how the modes differ from each other, try playing them all *from the same starting note*. For example: C lydian: C D E F# G A B C C ionian (major): C D E F G A B C C mixolydian: C D E F G A Bb C C dorian: C D Eb F G A Bb C C aeolian (natural minor): C D Eb F G Ab Bb C C phrygian: C Db Eb F G Ab Bb C C locrian: C Db Eb F Gb Ab Bb C
This takes time but you will get the hang of hearing the differences. Here is a link to help. http://www.good-ear.com/servlet/EarTrainer?chap=3&menu=2
I'm with Richard on this one the "key" you are in depends a lot more on where you hear the root note and the relation of the intervals relative to that than it does on what "absolute" note names you are playing. Just because D Dorian is all naturals does not mean that when you play around on this scale, you are in C major! A lot closer to D minor, actually, in terms of how a modal style "implies" a particular key. For those of you interested, it's worth noting that the modes based on Ionian (the major scale) as listed above are not the only ways of getting up an octave in seven tone or semitone steps. There are other modes that divide the octave scale into the same number of tone/semitone intervals in a different order - they're called synthetic modes and can certainly be interesting to play around with!
Whuuuuu? Why on earth would you play D dorian over C minor anything? that would leave you with a major third and seventh . . .
I recent left modes and scales behind. I used to think modes and scales was the be-all and end-all to playing bass. I only use chord patterns now, which are easier to use than scales, and far more interesting. I've substituted scales for 3 basic patterns: - wholetone/wholetone - wholetone/halftone - halftone/wholetone
Chord patterns? Funny, because as a keyboardist, we start out playing with chord patterns and then have to learn to play more scale-based.
I do use scales for constructing melodies though. But as a rhythm instrument, I'm more concerned with constructing harmonies rather than melodies.
Scale/mode theory and chord theory are really all the same thing anyway AFAICS. To try to do one without the other doesn't make sense to me. My $0.02
Ok, thanks for the answers. I think I went off a bit from my original question, though I think now that it has no answer. This was touched on a bit in The Jazz Theory Book (well, it probably went into lots of detail, but I'm going slow). He'd write something like "this is a II-V-I progression in the key of F" while the key sig was C. I found it hard to adjust to, not least because it takes me ages to work out the keys by looking at the chords.
Look for dominant chords. A whatever 7 is ALMOST ALWAYS going to try to resolve up a 4th/down a 5th. C7 is the V7 chord of Fmajor D7 is the V7 chord of G major E7 is the V7 chord of Amajor etc etc etc So if you have a progression that goes /C-7 F7/ all you have to think is "What's a 4th down from F?" or better "What is F the 5th degree of?" And? Right, Bb. So if you have a progression that is /C-7 F7/ Bbmaj7 / Bb7 / Where's that Bb7 gonna go? Eb, right. So the progression is in Bbmajor for 2 bars and then has a bar of Ebmajor. Clear? You got a chart for ALL THE THINGS YOU ARE?
Yeah, I understand now, thanks. I've got that chart, and I'm having a look at it. At the head, the third bar is Eb7, which is the fifth of G#, so that's an annoying key.
The 5th of Ab, actually. It may seem like a quibble, because G# and Ab are enharmonic equivalents, but for purposes of understanding, it does matter to keep it straight.