???
When improvising when can I switch from one scale to another, for example, from a blues scale to a harmonic scale?? Exactly what are the do's and don't's from switching from one scale to another in the middle of a solo??? :)
Thanks 8)
:-*
follow the chord changes
For instance I have been working on some jazz in  ii V I  So I play Dorian, Mixolydian, Major on the changes
You can try doing some call an response type soloing. This works pretty well with blues. Play a phrase using the blues scale and then follow up with a phrase using the harmonic minor or major pentatonic or whatever.
I also will try and see how the scales overlay...what the common notes are. I'll tend to pick one as "home base" kind of scale, then I'll slide, bend, hammer on, etc to incorporate the notes of the other scale.
Experimentation is the key. Sometimes an abrupt change will work other times you might have to find a way to walk from one scale to the next.
Happy jamming,
Olive
"My ex-boyfriend can't tell me I've sold out, because he's in a cult, and he's not allowed to talk to me." --Dar Williams
When improvising when can I switch from one scale to another, for example, from a blues scale to a harmonic scale??
You can play a blues scale over Dominant 7th chords and regular major and minor chords and power chords or just a single root note or even as a stand alone riff.
Harmonic Minor works when a V7 is going to a i minor chord like on E7 to Am you could play A harmonic minor.
Now this ain't the LAW these are just some suggestions.
Exactly what are the do's and don't's
It's all in the chords or a sequence of chords.And sometimes just a portion of a sequence.
Like in that  ii V I example you could play Dorian over the ii and the V because you can pretend it's a i IV in Dorian just for those two chords.Then you can play Ionian on the I chord.
Really you can do that 'OR' you can do what Nick said and switch scales on every chord 'OR' you can view all three chords as Ionian.And THAT'S how you want to look at all chord progressions.See if you can play one scale for the whole thing or if you can switch scales on some of the chords.You can always (well most of the time) change scales on every chord but that's a bit of a pain,or can be.You want to pick your spots.It just depends on the progression.The chords are your buddies.They'll always point the way  :D
im not sure if the question was that 'deep'
just make sure its not like from D Aeolian to F Lydian (unless you want that effect)
stick with related scales, is my advice.. and if you want to go from minor to major use like
harmonic minor
aeolian
dorian
mixolydian
lydian
ionian
that kinda bit by bit getting more "majorish"