Originally Posted by: decpestOk, say the key is "C" and we have a standard 12 bar blues. Does this open the , in addition to the C major Penetonic scale, the C minor, A minor, and the extended C major scale into the F and G majors and minors upon chord changes, or am I completly insane?

Hi! Oh man, this is all confusing and pretty hard stuff, but enough practice and you WILL get that AAAH moment!!

I assume you're talking about a major blues, a minor blues will be less flexible.

Well, if we're talking about the major blues here - a standard C major blues - the chords would be (I) C7, (IV) F7, and (V) G7. The one, four and five chords.

A very good place to start is to learn the ARPEGGIOS of each of those chords, and play a few rounds of 12 bars just following the chords - play C7 arpeggio on the C7 chord etc.

Now, blues doesn't really sound good or very bluesy if you just play the arpeggios up and down - BUT - you learn which are the sweet sounding notes over each chord - those are gonna be notes within the arpeggios - and thus, safe notes to land on!

OK - to the scales:

Blues is very flexible and if you have the right attitude, any note can sound good, haha! However, it might be easier to start off with a few scales.

- Over the I chord - C7 in this case:
C Minor pentatonic scale will sound good
C Major pentatonic scale will sound good
C blues scale will sound good.
C7 arpeggio will sound pretty good (maybe a bit stiff)
C dorian scale will sound pretty good (same notes as Bb major)
C Mixolydian scale will sound pretty good (same notes as the F major scale)
A minor pentatonic will sound good because it has the exact same notes as the C major pentatonic scale.

Wow, as you can see, there are lots of options here, and you don't just wanna play the scales up and down trying to cram as many notes in there as possible. Pick one, develop a good idea, follow that for the chorus, and then maybe switch it up a bit for the next round of 12 bars.

- Well, on to the IV chord - F7.
Staying in the C blues scale, C minor pentatonic or C dorian will sound pretty good, as those scales contain some, or all, of the notes in the F7 chord. You need the C Dorian though to really hit the major third (A) of the F7.

F major pentatonic scale will sound good
F mixolydian will sound pretty good (contains F7 arpeggio)
F7 arpeggio will sound good

- The V Chord - G7
Again, staying in the C blues scale will work, as the listener's ears are already tuned in to that sound.
G major pentatonic will work ok
G7 arpeggio will work
G mixolydian works ok, but might not sound too bluesy

Well - a simpler way of going about it is to just play the C blues scale all the way through - adding notes from the arpeggios of each chord tastefully.

I know that all of this can be very confusing, so please ask more if there are things that are still very unclear!