I've Got The Blues.

HI

I've been playing guitar for 13 years but just recently decided to learn to apply music theory to the guitar. I had a basic level of music theory from piano lessons when I was younger so getting started wasn't too daunting.

I'm using many different resources in my quest to be able to understand what the hell Joe Satriani is talking about in his interviews and I recently purchased some DVDs from LIck Library by Danny Gill. Learning Harmonized Theory, Beginner, Intermediate and Advanced.

I worked my way through the beginner DVD fine and now half way through the Intermediate I've lost my way a bit and become a bit confused. And when searching other sources to find the answer I find myself getting deeper into a hole.

Thats when I decided it was time to make use of the GUITAR MASTER CLASS forum.

My problem is with the blues.

This is what I know. ( Or think I know )

A blues progression is made up of chords 1, 4 and 5 of the chosen key. So if we were using the key of C our chords would be C major, F major and G major. However the DVD also says that ALL blues chords are Dominant 7 chords. I know that by adding the 7th interval to the major triad you get a 7 chord. So C major becomes C major 7, F major becomes F major 7 and G major, being the 5th, is the Dominant G7.

So this is where my confusion starts. Why is it that the 1 and 4 chord are also Dominant 7 chords when it comes to blues?

Also when searching for the answer to this I found formulas for chords where the dominant 7th chord was 1, 3, 5, 7b. But the DVD said nothing about lowering the 7th down half a step for the dominant 7th chord.

So what is the correct way to build a dominant chord?

Its so strange that a style of music I love and have played for years is causing me so much confusion!

So to review my questions.
Why are the 1 and 4 chords dominant chords along with the 5th?
What is the correct way to build a Dominant 7th chord?
Also going back to the key of C example, if it is the case that 1, 4 and 5 are all dominant 7 chords, does that mean I would need to solo over the C7 chord (1 chord) using the F scale where C major is the dominant 7 chord, over the F7 (4 chord) I would use Bb scale where F major is the dominant 7th chord and finally when soloing over the G7 I would use the C scale where the G major is the dominant 7th chord.

I think you can tell how confused I am now! And I apologize if I've made any basic errors with what I think I know!

So thats it.
Any help will be great.
Thanks!!!
Roach