Rack-mounted equipment usually follows a standard set of dimensions, including 19” (483 mm) for width, and a “rack unit” (or U for short) for height equaling 1.75” (44 mm) per U.
Many common modular synthesizer formats follow the rack unit system for standardizing module height – such as 3U (3 x 1.75 = 5.25” or 133 mm) for Eurorack, 4U for Buchla and Serge, and 5U for classic modular Moogs (sometimes referred to as MU for Moog Unit).
« Back to Glossary Index