This text was copied from Wikipedia on 27 March 2015 at 6:01AM.
In music, a catch is a type of round or canon at the unison. That is, a musical composition in which two or more voices (usually at least three) repeatedly sing the same melody, beginning at different times.
In early collections catch and round were interchangeable and, with part-songs and multi-voice canons, were all indexed as "songs". The catch and round differ from the canon in having a cadence on which the song can terminate after a specified number of repeats or when the leader gives a signal. The notion that a catch necessarily requires the lines of lyrics to interact so that a word or phrase is produced from one part in the rests of another became prevalent in the later part of the eighteenth century. This was under the influence of the competitions sponsored by the Noblemen and Gentlemen's Catch Club from 1761 onwards. Thus, Hawkins (vol. ii.) definition as that species of round 'wherein, to humour some conceit in the words, the melody is broken, and the sense interrupted in one part, and caught again or supplied by another'. is by no means universal.
Catches were originally written out at length as one continuous melody, and not in score. The change to printing in score was first made by Maurice Greene (composer)(1696-1755) who became Master of the King's Music in 1735, and this is now the usual method of presentation. In the score for a catch the different voices are usually labelled, "1", "2", "3", etc. This indicates that voice "1" sings its part first. When the part has been completed it is sung by voice "2" and so on. A common mistake in performance is for all parts to start together as though the score were to indicate a part song.
As noted under round the earliest secular piece of interest is Sumer is icumen in from the thirteenth century. Though there may well have been many more over the years, few survived and the first substantial collection is a single manuscript written out by Thomas Lant, dated 1580, containing 57 catches and rounds. Only seven of these songs were not included in one of the three publications (1609-1611) by Thomas Ravenscroft and the Scottish MS by David Melvill (see reference 1). Between them these sources give 145 catches mostly from the C16; two drinking songs have been ascribed to Orlande de Lassus but the remainder are obstinately anonymous.
Some significant composers of catches in later years were Henry Purcell (A catch upon the viol ), Michael Wise (A catch upon the midnight cats ) and John Wall Callcott. Callcott's best known catch Sir John Hawkins' History of Music  ridiculed Sir John Hawkins' work by comparison with a similar work by Charles Burney. An example of a particularly lewd catch is My man John  by John Eccles.
One of the most prolific of modern composers of catches is Donald Sosin, who has written dozens of them for special occasions and a variety of vocal groups since learning the craft from his composition professor Dennis Riley at Columbia University in 1974.
- We took off our ugly clothes
- And put on our tails again
- We combed our hair
- We're beautiful to look at
- We feel immense joy
- To be in your city
- Of course we'll tell you who we are
- We could never forgive the omission.
Which resolves into the phrase "Men's Glee Club, University of Michigan", with the second syllable of immense forming the word men's, the second syllable of ugly forming the word glee, and the first syllables of the words clothes and beautiful combining with never and city to form the word club and the word university, and so on. You can listen to this catch on SoundCloud.
Another well-known example is the "Liverpool Street Station Song", beginning, "The girl that I love has given me the shove \\ She says I am too low for her station".
Two main composition techniques are used for making the message audible: using rests in other parts that don't have a part of the message (for example, in Uitdenbogerd's "A Big Laugh" (2007), one part has "ha (rest) ha (rest)" while the other part has "(rest) don (rest) don" to make the message component "hard on, hard on"), or using the highest notes at any time to be the message melody notes. Those that rely on the second technique tend to be less obvious in performance unless emphasised. A performance technique used by Uitdenbogerd for Australian Intervarsity Choral Festival revues is to sing the catch in unison, then in parts, then with message words emphasised, and then finally only the message words. This technique only works for catches that have a message that spans the entire phrase. This method of performance has led to a new innovation in catch-writing, pioneered by M. Winikoff, in which a recognisable message melody is embedded within the catch.
Catches in popular music
Dashboard Confessional used a catch in the chorus of the song "Hold On" from the album The Swiss Army Romance. The chorus line is "It's cruel but she's got a good hold on me", which when sung as a canon causes the message "Screw me" to be heard.
The Art of the Ground Round by P. D. Q. Bach uses several catches. "Loving is as easy" uses a catch to form the words "hot dog", and "Please, kind sir" combines "look, her face could launch a thousand ships" and "she's up dressing, she'll be down in a jiffy" to create "look up her dress".
- Eg Ravenscroft 1609-11 see Aldrich Book of Catches vol3 (Ashworth Informatics, 2008)
- Sir George Grove, ed. (1909). Grove's dictionary of music and musicians, Volume 4, p.165. The Macmillan company.
- A.L. Uitdenbogerd, "Sandra's Book of Rounds, Canons and Catches", , 2005
- Bach, P.D.Q. The Art Of The Ground Round For Three Baritones and Discontinuo S 1.19/lb. Bryn Mawr, PA: Theodore Presser Co.
squarely edited by Peter Schickele