When I hear a guitar player like Joe Bonamassa on YouTube playing a solo (fast) without any accompaniment and it sounds great , I always wonder how they do it. I can improvise over chord changes and sound halfway decent because I'm harmonizing, but with out that I don't sound very good. Are they using chord tones more often which implies harmony or is it something else ?
It is difficult to play melodic lines which don't sound like scale patterns. For that you need a good (I dare say) natural melodic sense but also there are some tricks that help you in getting a focused melodic sound.
- You can stress root notes /tone like a superfast drone note, but that is almost like harmonizing
- There is a good technic on drawing chords, so people learns scale patterns or licks that "draw" a chord virtually, so a solo can be comoposed by a mixture of different patterns which indeed, are drawing again an harmony
- Playing modal or bluesy and knowing the alterations for those can help you to make surprising melodies, since you are again, changing the underlying harmony. Somo intrincate jazzy solos make heavy use of those.
I assume you know how chords are formed, in that case a basic chord drawing is playing 1-3-5, specially 1-3 which gives you a more typed tonality.
For me a good melody is always one that helps you understanding the harmony. If you whistle Greensleeves, you'll se the melody is powerful because it is imposing you a bit the chords, tone and modality. On the other hand, it is surpring if you remove accompainment to Beatles' Julia. In the first line, you'll find your self snging the same note like ten times but your brain thinks it is recognizable because you have the 2 chord changes on the background in your head. If you remove them, it is surprinsing is simply a boring monotone.