The Hammond B3 organ is unique among keyboard instruments because of its 'drawbars.' Instead of using preset sounds, a Hammond player uses nine sliding bars to control the volume of various harmonics (overtones). This process is known as additive synthesis. By pulling different combinations of drawbars, the player can create thousands of unique tones, from a pure, flute-like sound to a gritty, 'dirty' roar. The drawbars are modeled after the stops of a pipe organ, with lengths like 16', 8', and 4'. This flexibility made the Hammond a staple in gospel, jazz, and rock music. It allowed musicians like Jimmy Smith to mimic the sounds of a big band or Keith Emerson to create aggressive rock textures. The 'percussion' setting on the B3—which adds a sharp 'ping' to the start of each note—is also a defining feature of the instrument’s iconic sound.