wah-wahn.

1926 H. O. Osgood So this is Jazz 98 Then there is the clown of mutes. Leading philologists of the jazz world are at odds over the correct spelling of the name; some favour wow wow, others prefer wha wha, but there is authority for the simplification wa-wa.

1936 Amer. Mercury 38 p. x/2 Wah-wah, a brass effect gotten by favoring a bell of a horn with a mute.

1949 R. Blesh Shining Trumpets (new ed.) viii. 183 The ‘wa-wa’, produced by the cupped hand moved in front of the cornet or trumpet bell.

1950 A. Lomax Mister Jelly Roll (1952) 64 There were many other imitations of animal sounds we used—such as the wah-wahs on trumpets and trombones.

1976 New Musical Express 12 Feb. 25/2 You can thrill again to..Clapton playing his insidious wah-wah on ‘Get Back Home’.

1977 ‘E. Crispin’ Glimpses of Moon iii. 38 One spends his working life in a perpetual seascape, another writing wah-wahs on trumpet parts for people surfacing in mud-baths into which they have comically fallen..and so on.

1938 D. Runyon Furthermore viii. 156 Something goes wa-wa, like a sheep..because..Isadore is sitting on John Ignatius Junior's doll, which says ‘Mamma’ when you squeeze it.

1958 H. M. Hayward & M. Harari tr. B. Pasternak Dr. Zhivago i. vi. 158 ‘Wa, wa,’ yelled the babies all on one note... Only one voice stood out from the others. It was also yelling ‘wa, wa’,..but it was deeper.

1925 G. Gershwin Rhapsody in Blue (music score) (1939) 1 (direction) Wha Wha effect.

1926 Melody Maker Feb. 23/2 (advt.) The wow-wow mute is made of spun aluminium.

1926 P. Whiteman & M. M. McBride Jazz ix. 200 The first time I ever heard what I call the wawa mutes, used with the cornet... The players got that effect by inverting glass tumblers over the bells of the instruments.

1930 R. Paget Human Speech 240 The so-called ‘wow-wow’ mutes for cornets and the like.

1935 Vanity Fair (N.Y.) Nov. 71/3 The wah-wah notes of intermittently muted brass.

1943 R. Blesh This is Jazz 24 This bad tone..like dirty tone, growl or wah-wah trumpet work, is expressive and therefore good from the Jazz point of view.

1954 Grove's Dict. Music (ed. 5) IV. 601/1 The trumpets and trombones very frequently use peculiar mutes, such as the ‘wa wa mute’, which can make the instrument weep or laugh rather like a human voice.

1969 It 13–28 June 13/2 Frank proved quite conclusively that he's a brilliant guitarist, especially with a ‘wah-wah’ pedal.

1979 R. L. Simon Peking Duck xxiii. 175 It's an old song... Now they use a wah-wah pedal and a Moog Synthesizer.

1968 Life 15 Mar. 8 (heading) Brash buccaneer with a wa-wa.

1969 Official Gaz. (U.S. Patent Office) 2 Sept. tm25/2 Wah Wah. For musical auxiliary amplification and attenuation tone devices, consisting of a pedal and an electronic circuitry housing for use with electronic musical instruments... First use Apr. 3, 1967.

1975 Guitar Player Sept. 9/2 I remember that on that cut Jimi used his Strat and his wah-wah. He actually practiced with his wah-wah and it wasn't a gimmick.

1978 Eng. Jrnl. Dec. 23/1 Why would anyone want a nine month old wa-wa, and pay $500 for it to boot?

1989 Guitar Player Mar. 14/1 Trower likes a wah-wah for the ‘vocal quality’ it gives the guitar.