Yet another modal question.

Key signatures tell you what accidentals are in the perticular key, so in the case of D dorian (the mode you mentioned) it would have the key signature of C major, alot of notation i've seen usaully will tell you if it is modal.

If I took the subscale DEFGABCD, would this be C dorian, or would it be D Locrian? (I think I got those right, it has been difficult to articulate this question in my mind.)

That is the Dorian mode in D.

Im not quite sure what youre getting at but, I hope this helps. These are the intervals of those modes:

Ionian: W W H W W W H

Dorian: W H W W W H W flat 3rd and 7th note

Locrian: H W W H W W W flat 2nd, 3rd, 5th, 6th and 7th note

Hope that helps.

Modes use the same key signatures as their relative major scale - just like relative minors use the key signature of the relative major. So there's no special notation.

So if I'm in the key of C...

DEFGABCD would be D dorian, meaning that you take the root of the subscale (D) (or, rather, the first note in the scale) and the modal name corresponds to the key it's in?

It makes sense now.

Now, I know that I didn't really phrase it correctly... (and I don't know where I got D locrian from, I must have been a bit out of it) but i wanted to know if you went by the key signature or the first note in the scale. My initial "C dorian" came from the key signature (C major) and the position of the scale (second degree, so therefore dorian). But I realize now that the notation goes by the first note in the scale (in this case, D) and the degree of the scale relative to the key it's in.

I know I complicated it a bit...in practice, I konw the stuff, but when I tried to put it together with key signatures and whatnot, it got a bit, er, rumpled.

Thanks, guys.