Fundamental question: scales

[rbarata]

How do you know, in a song, which scale to use as a basis for a guitar solo?

[Ogg Vorbis]

How do you know, in a song, which scale to use as a basis for a guitar solo?

There might be more than one scale you'd use, depending on your chords and where they go.

For example, if your song is going along with Am7 for 8 bars, then changes to Cm7 for 8, then you'd have a problem getting ONE scale to fit both.

Even if your chords go Am7 for 4 bars than to F7 for 4 bars, then again your solo is going to have to do some shifting.

What I might suggest is to figure out what scale or scales your melody uses, and then derive a solo which is based around that.

The guiding principles for choosing a solo scale or scales are: where do your phrases cadence (resolve or "land")? What scale or scales match the chord tones and where do you want to go melodically?

In my opinion, your melodic direction should dictate what scale you would use, rather than the other way around.