Digital audio stores the level of each sample as a number with a given resolution, measured in bits. A bitcrusher deliberately reduces that resolution. Fewer bits mean larger rounding errors, heard as grainy noise and distortion: Apple’s Bitcrusher, for example, can be set anywhere from 24 bits down to 1, at which point the distortion can overwhelm the signal itself. Most bitcrushers also offer downsampling, which adds the metallic tones of aliasing.
The effect echoes the sound of early samplers whose 12-bit converters, in machines such as the E-mu SP-1200 and the original Akai MPC60, are part of the texture of classic hip hop. In jazz lo-fi, light bitcrushing on drums or a sampled loop adds crunch and a sense of age, while heavier settings quickly turn harsh and glitchy.