hello every1 at UG. I recently just bought Paul Gilbert"s "get out of my yard" dvd and while he's talking about whatever, he keeps saying things like "then u play this in key of........ (whatever key it was in)" and i was just floored by all these terms he was saying. Now my question is, what the hell does all this mean? I know about the chords and such, but I'm not completely sure how you tell what key something's in. I'm still pretty new at playing guitar, so is he talking about is music theory or what? Cause im kinda dumbfounded by music theory. Help!
trying to learn from paul gilbert when your a new guitarist is like taking off your training wheels and biking the tour de france or something.

definitly study some theory, guitar and music in general will make a lot more sense. my suggestion would be a teacher, but if thats not an option, there are tons of theory lessons online

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well if he said that it was in the key of, say "A", its kinda the same as saying the A major scale. I would advise looking up scales, on this site, http://www.all-guitar-chords.com/guitar_scales.php ... and as for chords and scales, it depends on the context that the chord is in but ultimately people play what ever they feel sounds good.
To try and answer the question, the key a song is played in is the chord it is based on. Take a simple song like Johnny B Goode, usually played in the key of A. That means the song is based around an A chord. It starts in A, the first line of the vocals is in A, it ends in A. That makes A the Root chord of the song, or the key it's played in. That's an explanation on a diet...but basically it.

Here's a list of other Musical Terms you might run across.
Hmmm...I wonder what this button does...