[solidwalnut]

Originally Posted by Fretsource

This ties in with another thread where I've been discussing something similar with Monk and Scotty.
Kirk is right. In tonal music, technically, you're still playing in the Ionian mode throughout, because the mode is determined by the KEY and note set of the song, not the ROOT of the current chord.
This is the original use of modes from medieval melodies up to the modal jazz explorations of Miles Davis and his contemporaries and successors.
The fact that F Lydian has the same notes as C Ionian is just a coincidence. But it's a coincidence that has been exploited in the rock world because, as Monk and Scotty pointed out in that other thread, it offers a convenient way of planning out your path through the chord tones.
The downside of that approach is that, without enough information, it can lead guitarists into misunderstanding what modes actually are, and into thinking that they're playing in a mode, when in fact they're not, or at least not the mode they think it is.

It's a bit like using a capo. If playing alone, I can play a song in G and I can then stick a capo on fret 3 and play it as before. It's perfectly fine and very convenient to think of it still in G, especially if I'm reading from a chord sheet, but I know I'm actually now playing in Bb.

It's the same with modes. Thinking of our notes as belonging to F Lydian when we play over F major in the key of C may offer some help in knowing where we are and where we're going - but it's not actually F Lydian at all, it's C Ionian.

Fret--

I get all this. This makes sense. Aside from the fact that modern folk and rock have stolen or misconstrued the concept, what name do we give what we're hearing? It may be strictly speaking the Ionian mode, but we definitely hear something different when we play the major scale intervals from a different starting point other than the root.

Steve