ronster wrote:So is the scale considered D ionian because key is D or B aolean because of the Bm chord with the B root note?
Also does the mode always have to do with the key of the song or does it change with the chord being played?
It is considered B aeolian because the Bm is the main chord so to speak, but I wouldn't limit yourself to just that way of thinking (however if you were fast enough & wanted to think of it like that, you could essentially be playing a B aeolian, A mixolydian, and G lydian, but I think it gets a little too confusing when you do that).
My advice would be to play over the changes while knowing what notes are "available" to you. This is when it comes in handy to know the entire pattern when soloing in a song, that way you don't have to think too much about what mode you're in. Think of it as being in the key of D, like you said, but be able to visualize all those modes at once. Tough at first, but practice all of them up and down the neck and you'll soon realize how easy it is, and you'll see how much the fretboard will open up for you. It may seem like a big place at first, but really - look at it. It's not that big at all. Only 12 notes no matter which way you go or what string you're on. That's it, just 12. They just happen to be in different places.
I think someone else already mentioned this, but learn to play B aeolian while starting on the low E string, then learn it on the A, the D, the G, the B. Know how to play it front and back, and you'll soon realize that you actually know all the patterns in whatever key it is that you are in (in this case, D).
Hope that makes some sense....
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