In jazz and blues, a blue note (also "worried" note) is a note that—for expressive purposes—is sung or played at a slightly different pitch than standard. Typically the alteration is between a quartertone and a semitone, but this varies among performers and genres. Blue notes may be marked by a glissando or trill.
The blue notes are usually said to be the lowered third, lowered fifth, and lowered seventh scale degrees. The musicologist Peter van der Merwe also includes the diminished sixth, noting it as the least frequent type of blue note. The lowered fifth is also known as the raised fourth.
Blue notes are used in many blues songs, in jazz, and in conventional popular songs with a "blue" feeling, such as Harold Arlen's "Stormy Weather." Country blues, in particular, features wide variations from the diatonic pitches with emotive blue-notes. Blue notes are often seen as akin to relative pitches found in traditional African work songs. Blue notes are also prevalent in English folk music and Irish traditional music (in Ireland they are called long notes).
Though the blues scale has "an inherent minor tonality, it is commonly 'forced' over major-key chord changes, resulting in a distinctively dissonant conflict of tonalities". A similar conflict occurs between the notes of the minor scale and the minor blues scale, as heard in songs such as "Why Don't You Do Right?", "Happy" and "Sweet About Me".
In the case of the lowered third over the root (or the lowered seventh over the dominant), the resulting chord is a neutral mixed third chord.
- Benward & Saker (2003). Music: In Theory and Practice, Vol. I, p.359. Seventh Edition. ISBN 978-0-07-294262-0.
- van der Merwe, Peter (1989). Origins of the Popular Style: The Antecedents of Twentieth-Century Popular Music. p. 119. ISBN 0-19-316121-4.
Like the blues in general, the blue notes can mean many things. One quality that they all have in common, however, is that they are lower than one would expect, classically speaking. But this flatness may take several forms. On the one hand, it may be a microtonal affair of a quarter-tone or so. Here one may speak of neutral intervals, neither major nor minor. On the other hand, the lowering may be by a full semitone--as it must be, of course, on keyboard instruments. It may involve a glide, either upward or downward. Again, this may be a microtonal, almost imperceptible affair, or it may be a slur between notes a semitone apart, so that there is actually not one blue note but two. A blue note may even be marked by a microtonal shake of a kind common in Oriental music. The degrees of the mode treated in this way are, in order of frequency, the third, seventh, fifth, and sixth.
- "Blue Notes". How To Play Blues Guitar. 2008-07-06. Retrieved 2008-07-06.
- Ferguson, Jim (1999). All Blues Soloing for Jazz Guitar: Scales, Licks, Concepts & Choruses, p.20. ISBN 0786642858.
- Lloyd, A.L. (1967). Folk Song in England, p.52-4. London: Lawrence & Wishart. Cited in Middleton, Richard (1990/2002). Studying Popular Music. Philadelphia: Open University Press. ISBN 0-335-15275-9.
- Epping, Rick. "Irish Harmonica". www.celticguitarmusic.com. Retrieved 2008-11-04.
- Schuller, Gunther. Early Jazz: Its Roots and Musical Development (New York: Oxford University Press, 1968), pp. 46–52). Cited in Benward & Saker (2003), p. 39.