Motion Sound is an American manufacturer of keyboard amplifiers and rotary speaker systems, founded in 1994. The company designs and builds all of its products in the USA, specializing in premium amplification tailored for keyboard players, organists, and pianists. Motion Sound is particularly recognized for its rotary speaker systems — the Pro-3X rotary horn speaker and the Pro-145 rotary speaker system — which deliver authentic Leslie-style rotating speaker effects in portable, modern form factors. The Pro-3X features a proprietary variable-mode FET preamp, while the Pro-145 offers a complete bi-amped 200-watt rotary system with both a rotating horn and rotating drum.

Beyond rotary speakers, Motion Sound produces a full line of stereo keyboard amplifiers and passive speaker cabinets. The KP-1000S series provides high-wattage stereo amplification for live performance, while models like the KP-612SX deliver 500–1,000 watts through configurations using Faital Pro drivers. The company also manufactures guitar-oriented rotary speaker cabinets, including the SRV-112 and SRV-212 Sidewinder series, which bring rotating speaker tones to guitarists in a more portable format than vintage Leslie cabinets.

Motion Sound counts several prominent keyboard players among its endorsed artists, including Yes keyboardist Rick Wakeman, his son Adam Wakeman, and jazz organist Joey DeFrancesco. The brand is sold through major retailers including Sweetwater, Guitar Center, and Musician's Friend.

Motion Sound has 3 products cataloged on Equipboard, including Speakers & Accessories, Guitar Amplifier Cabinets, and Keyboard Amplifiers. Their gear is featured by 2 artists, with the strongest followings in Rock and Pop. Notable users include Butch Walker and Dan Palmer.