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.
William F. Ludwig made the bass drum pedal workable in 1909, paving the way for the modern drum kit.[12] A bass drum pedal operates much the same as the hi-hat control; a footplate is pressed to pull a chain, belt, or metal drive mechanism downward, bringing a beater or mallet forward into the drumhead.