Instrumental Technique

The third characteristic lies in the "hot intonation" of jazz instruments, a feature inadmissible in classical music but imparting to jazz its special character. It is produced by a sharp attack, sustained vibrato, with constant use of the glissando, and lends a tone rougher and more uniformly intense than that attained in classical music. Sustained emotional intensity is produced not only by the above but also by the "blue" note, the fourth characteristic. The third and seventh in all Negro music from spirituals to hot jazz are not pitched steady. They are "worried" wavering between flat and natural, and contributing an especially poignant quality.