Noun
wah-wah pedal (plural wah-wah pedals)
(music) A pedal for an electric guitar that mimics the sound of the human voice.
Miles Davis would have this lineup of all these amazing musicians and one day would just say, 'We're done.' After tons of great records and tickets sold, he said, 'Now I'm going to grow my hair out and play my horn through a wah-wah pedal.' Rather than play it safe, he went on. Henry Rollins