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.
By using a looper pedal, a singer-guitarist in a one person band can play the backing chords (or riffs) to a song, loop them with the pedal, and then sing and do a guitar solo over the chords. Some units allow a performer to layer multiple loops, enabling the performer to create the effect of a full band.