In music, wah-wah is used to describe the sound produced by covering and uncovering the open end of a brass instrument. This sound can also be produced electronically, especially when playing the electric guitar.
He played some wah-wah guitar.
wah-wah in British English
(ˈwɑːˌwɑː)
noun
1.
the sound made by a trumpet, cornet, etc, when the bell is alternately covered and uncovered: much used in jazz
2.
an electronic attachment for an electric guitar, etc, that simulates this effect
Word origin
C20: of imitative origin
wah-wah in American English
(ˈwɑˌwɑ)
US
noun
1. Jazz
an instrumental effect somewhat like that of the sound of a baby crying, produced by closing and opening the bell of a trumpet, trombone, etc. with a plunger mute held in the hand
2.
a similar effect created by an electronic device controlled by a foot pedal, that can be used with any musical instrument