scordatura
An alternative tuning of a stringed instrument to achieve unusual effects.
In Depth
Scordatura means mistuning — deliberately retuning one or more strings of a string instrument to a non-standard pitch. This can extend the instrument's range, create unusual resonances, change the tonal colour, or make otherwise impossible passages playable. The technique has a long history in string music. Baroque composers used scordatura extensively, and Heinrich Biber's Mystery Sonatas use 15 different tunings across 16 sonatas. In orchestral music, the most famous scordatura is in Saint-Saëns's Danse macabre, where the solo violin tunes its E string down to E♭ to create the tritone (the devil's interval) on open strings.
In Saint-Saëns's Danse macabre, the solo violinist tunes the E string down to E-flat, creating the tritone — known in the Middle Ages as the devil's interval.