A hexatonic scale is any scale consisting of six pitches. There are numerous ways to construct such a scale, but some of them are used more often than others and even have their own names. The so-called tritone scale is a hexatonic scale constructed from two triads related by a tritone. For example, combining the pitches of an A major triad and those of an E-flat major triad forms an A (or E-flat) tritone scale. (Note that an A tritone scale uses the same pitches as an E-flat tritone scale.)
Scales are a convenient way to describe the pitch content of a song and to identify the key or pitch center of a piece or an excerpt of a piece. But if a composer is said to use a particular scale in a composition, that doesn’t necessarily mean it will be spelled out or used in its entirety. It’s possible that the composer isn’t even aware they are using a particular scale and might be thinking of the pitch content in a different way altogether (like as a combination of chords as discussed above.)
The piece below, Blue Blues, simulates a blues tune using the notes of an A tritone scale. Some of the pitches are spelled enharmonically to make the piece a bit easier to read. Can you find a section of the piece where the pitch center briefly changes? What scale could be used to describe those measures?
(Please consider supporting this site! Sheet music and tablature for Blue Blues and other guitar studies available here: Innovative Studies for Guitar – Volume 1)