I just don't get it.... help

So it is the melody over the chords that tells us what the mode is.

Not quite.  The melody can be thought of as standing alone (not when the song is being listened to, of course) when it is analyzed.  It will have a note it centers on, and a set of notes making it up determining whether it is modal or not.  That same melody could be played over any chords and still be in the same mode.  The sound of the song as a whole, however, would be totally different.

******
(Look, I've picked up Alex's asterisk trick!)

Feel free to call me on this if I'm completely wrong (or only partially wrong), but I'm not, am I?

Yeah thats what i was trying to explain i know..

i know, i have two bad habits on forums, like nearly every time i finish a sentance i just leave a gap, therefore you never know when ive started a new paragraph (section) so thats when i stated using the asterisks..

lol.

You do have it :) Well, unless we got the same impression of what is right and we are both wrong..

Anyone who is clearly cleverer care to tell us if we are right?

Alex,

I wasn't disagreeing with the earlier discussion as I quite agree.  

I was just adding a practical note on how to use all this (scales/modes) when it comes to improvising, since this is where most people get hung up.  Obviously, I wasn't worried about staying modal here.  I figured that was self-evident -- stick to the notes of the mode.  

Noteboat, I like the way you explain things so much that I'm going to have to go look for your book, and I already have a good handle on this.  Thanks for the insights.

Glad you like the explanations, jstar - and thanks for the book order!

Tom

Paul, thanks for the explanation.  I know you are trying to make sure I understand but not to disappoint, that is actually what I meant that it is the melody over the chords that tells us the mode, ok so the chords dont have to be there, but i didnt say the chords all fall in the mode.  I meant what chords you play doesn't matter.  The melody establishes the tonic.

OK, I think I got it.  I posted on "Structure of a Symphony" about my music appreciation book and how it said that in plainchant, monks wouldn't use a set rhythm and they did not use harmony so they only way to create musical beauty/drama is with the melody and they are the ones responsible for this mode stuff.  Well, it is all quite simple (after only 40 posts about it).  The melody established the mode, even if I am playing crazy diminished and sustained chords behind it.  So if I play a simple chord progression in C - C F G - that can be C maj, d dorian, E phyrigian.. etc  It depends on the melody I am playing over it.  Although, it might help the mode along, or emphasize it, to have the chord pattern based around the tonic, (for modes based on C maj: Dmin, Emin, F, etc) .  You also don't have to stick to only chords in the mode, once again it is the melody although you want it to sound good so you shouldn't use any chord but you can jump into their major or somewhere else.  (I don't know (well, other than some scales) what note relationships give the most dissonance and which chords to avoid or ones that sound good ).  The closer the mode is to the ionian, the easier it is to "work" with because you don't run into too much dissonance.  Like mixolydian which I believe varies from ionian by a b7, or lydian by a b4.

I know they are not major scales or minor scales but you can say:
Major modes are Lydian, Mixolydian, and Ionian
Minor modes: Dorian, Phyrigian, and Aeolian (the natural minor)

The modes are major because for example, a G chord fits into the G mixolydian scale.  For the "minor modes,"for example D dorian has an F and a D chord has an F#, so to play the chord in the mode, it is a minor chord.    
The modes vary from their respective major by:
Dorian: b3 b7 - (this seems to me almost as a jumble of the minors, dont know if it sounds that way)
Phyrigian- b2 b3 b6 b7
Lydian  b4
Mixolydian  b7
Aeolian - b3 b6 b7
Locrian -  b2 b3 b5 b6 b7

I don't understand the point of changing modes every chord.  Does it might help in hearing or understanding the modes?  This is just for learning purposes right, because if not wouldnt it make a song atonal (atonal - this is what happens when you read books).

And Locrian is one crazy scale that usually should be avoided (unless you are Alex who enjoys challenges) - at least the monks knew better and didn't use it.

How did I do?  please correct what is wrong.
purple

Just a couple corrections, Purple:

Lydian has #4.  It's the only one that raises a tone instead of lowering one or more.

Changing the mode for every chord is done (I think) because it's an easy/lazy way to discuss the mechanics of modal music... whether or not you understand those mechanics!  I suspect that's one reason why people prattle on so much about modes.

Shifting modes constantly won't give you atonal music - the shifting emphasis within the melody line never leaves the key of the progression.  It will sound like a bad melodic line in C major, perhaps, but not an atonal line since there are no notes outside the key of C.

And you did great :)

I tried not too look back at any posts when giving my "quiz answer" so I must have wrote the scale for F out wrong, it has a Bb.  Thanks, It might have been awhile before I caught that mistake.  When discussing theory, I always reference everything to C for obvious reasons.  Why work with F# when you don't have to?

I see how shifting modes every chord (while playing a C progression) would just bring you to C.  I get it, your not really establishing a center but you are staying with in the notes of a C scale.

Thanks everyone for your help!  It is very much appreciated.

Purple

Another cool trick is to put intervals from the mode you want to use into the chords in a progression to sort of emphasize the mode without a lead.

For example:  For B Phrygian, you can take the b2 from the mode and use it as an alteration for the B minor chord.

Would this be using modes, since it could be part of a chord melody or something like that, or is it something else?

Purple, work with hard keys, it helps.. if you stick with C other keys become scarier..

like you said why work with an F# when you dont have to...

well... so that the F# doesnt worry you and you can look at Gmaj/Em (if thats what it was) and not be as uneasy about using it..

i always use complete random keys (but never C,F,G) when i do examples, it helps me get used to using them (and learning them)

Like i know my sharp keys, but not flats aswel as i want to, so i will spend ages just using flat keys till i know them comfortably enough to use..

and then they are all as easy as a beginner thinks "using C" is..

I think it does help learn scales and understand them, if that makes sense, like get to know, the fourth, fifth, sixth notes of them etc..