Wah and filter pedals manipulate frequency response to create expressive sweeps and vocal-like tones. The wah originated in the 1960s and became iconic in funk, rock, and blues. Notable wah pedals include the Dunlop Cry Baby, Vox V847, Morley Bad Horsie, and Xotic Wah. Envelope filters, like the Electro-Harmonix Q-Tron and Boss AW-3, react dynamically to playing intensity, creating auto-wah effects. These pedals are widely used for lead guitar articulation, funk rhythm grooves, and psychedelic textures, adding movement and expressiveness to performances.