Diagram of normal sinus rhythm as seen on ECG. In atrial fibrillation the P waves, which represent depolarization of the top of the heart, are absent.
The wah-wah pedal is based on a simple concept but its effect is far more dramatic. Using a powerful filter to sweep through a broad frequency spectrum, the wah pedal boosts and exaggerates specific tones. Creating sounds that range from thick, flubbery bass to scratchy, stinging treble.
The tone control reduces the amount of treble, affecting the pre-distortion EQ and thus the distortion voicing. For increased control of the pre-distortion EQ, place an equalizer pedal in-between the guitar and the first distortion stage such as a distortion pedal or the guitar amp's built-in preamp.