Key signature A minor as each accidental may be notated explicitly as required, or the piece may be modal or atonal. An example is Bartók's Piano Sonata, which has no fixed key and is highly chromatic. If not bound by common practice conventions, microtones can also be notated in a key signature; which microtonal symbols are used depends on the system. The common practice period conventions are so firmly established that some musical notation programs have been unable to show nonstandard key signatures until recently. The use of a one-flat signature developed in the Medieval period, but signatures with more than one
Avoid note Avoid note In jazz theory, an avoid note is a scale degree considered especially dissonant relative to the harmony implied by the root chord, and is thus better avoided. In major-key tonality the avoid note is the fourth diatonic scale step, or 11th, which is a minor ninth above the 3rd of the chord, and thus very harsh. In melody it is usually avoided, treated as a "scale approach note" or passing note, or sharpened. It is not available in harmony. The available tensions for a dominant seventh chord are 9, 11, and 13. In minor harmony the sixth scale