An equale or aequale (from Latin: voces aequales, equal voices or parts) is a musical idiom. It is a piece for equal voices or instruments. In the 18th century the equale became established as a generic term for short, chordal pieces for trombone quartet. Old church music regulations from Linz show that such pieces were used at funeral services in Austria. The performance of such pieces from towers on All Souls' Day and on the previous evening is associated with the funeral service. The theological meaning of the trombone as a symbol of divine presence, the voice of the angels and instrument of judgment is thereby underscored.
Notable examples of the genre are the three Equali for four trombones of Ludwig van Beethoven ("Drei Equales", WoO 30), written for performance in Linz Cathedral on All Souls' Day (2 November), 1812. Two of them were later performed, with the addition by Ignaz von Seyfried of words from the Miserere, at Beethoven's own funeral in 1827. They were also played as instrumental pieces at the funeral of William Gladstone in Westminster Abbey in 1898. The two Aequali in C minor of Anton Bruckner date from 1847 and are for three trombones. Three years earlier, in 1844, the little-known Wenzel Lambel (1788–1861) of Linz had published ten equali for three or four trombones. Stravinsky scored In memoriam Dylan Thomas, his setting of "Do not go gentle into that good night", for tenor, string quartet and four trombones, which may be an "echo" of the tradition.
- Sadie, Stanley (ed.) (1980). The New Grove Dictionary of Music and Musicians (Reprinted with minor corrections ed.). London: Macmillan. p. 218, volume 6. ISBN 0-333-23111-2.
- Brown, Maurice J. E. "Equale". Grove Music Online. Oxford Music Online. Retrieved August 2011. (subscription needed)
- From sleevenotes, Triton Trombone Quartet: "German Trombone Music"; BIS-CD-644
- Bellingham, Jane. "Equale (aequale)". Oxford Companion to Music. Oxford Music Online. Retrieved August 2011. (subscription needed)
- Mens en Melodie, volume 59 (in Dutch). Uitgeverij Het Spectrum. 2004. Retrieved August 2011.