The old jazz improviser’s adage is true: You’re never more than half a step away from the right note. You can justify any clinker by calling it a chromatic neighbor as long as you play it like you mean it and resolve it to a chord tone or to the correct upper extension. That raised seventh you played over the dominant chord–that was intentional, right? Love how you used it as a leading tone to the chord root! The major third you landed on in that minor seventh chord–how clever of you to create such unexpected tension en route to the minor third.
I’m joking around a bit, but what I’m saying is perfectly true: the difference between a clinker and chromaticism lies in how you handle the note.
Knowing about the half-step difference can help you when you’re sitting in with a group and find yourself playing a tune by ear whose harmonies you’re not familiar with. Barring tunes whose chords are all purely diatonic, you’ve got to identify the qualitative differences in borrowed chords. Modulations are a different matter; often, though, you’re dealing with just a chord or two out of the norm. Can you identify the note (or notes) that has been changed? It has only been raised–or lowered, take your choice–by just a minor second; otherwise, it would be diatonic to the scale.
Often the sixth note of the scale will be lowered to serve as the minor third in a IVmin7 chord, or as the flat 5 in a IImin7b5. Or the fourth may be raised to serve as the major third of a secondary dominant (V7 of VI). Or the tonic may be raised to serve as the major third in a V7 of II. The point is, if something in the harmony you’re hearing creates a clear qualitative difference, try to identify the tone or tones involved. You may be able to simply skate over the altered chord using a diatonic scale, as you can in rhythm changes, but you really should pay attention to it so you can make judicious choices about how to handle it. Doing so isn’t necessarily a matter of using a different scale; think instead of using the same scale with a note or two in it changed, or perhaps a note added. Your scale options can become more involved, of course, but it pays to start simply until you know what you’re dealing with.
Some tunes will stretch your ears if you work with them; others are too complex to simply jump in on. Speaking personally, my ears have their limitations. If a tune has a lot of modulations and odd harmonies, I have no problem with sitting out that number. But if I think I stand a chance of playing something convincing over unfamiliar territory, I’ll give it a try. Such on-the-spot listening and response is part of the learning curve of an improvising musician. Mistakes can be embarrassing, I’ll grant you, but don’t be afraid to make them. How else are you going to learn?
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