Langevin is a professional audio equipment brand with roots in the early 1940s in New York, where it began as a manufacturer supplying components to companies like Western Union and Hughes Aircraft, and grew during World War II as a second-source manufacturer for Western Electric. In the 1950s, the company moved to Santa Ana, California, and built its reputation on tube and solid-state recording and sound reinforcement equipment that became fixtures in broadcast and studio facilities. The brand shared a long history with Electrodyne in Santa Ana, with the two companies sometimes producing nearly identical electronics in different housings.

The Langevin trademark is owned by Manley Laboratories, which manufactures Langevin-branded outboard gear alongside its own line of tube products at its facility in Chino, California. Where Manley units lean on vacuum tubes, Langevin products are built around all-discrete transistor make-up gain stages, while sharing the same EQ, limiting, and metering sections as their Manley counterparts.

The Langevin catalog includes the DVC (Dual Vocal Combo), a 2U dual-channel strip pairing discrete mic preamplification with passive shelving EQ and electro-optical limiting, the Dual Mono Mic Preamp with EQ, and the Mini Massive stereo equalizer — a passive shelving EQ derived from the Manley Massive Passive design. The line is aimed at engineers looking for the character of discrete circuitry on vocals, drums, and tracking duties.

Langevin has 3 products cataloged on Equipboard, including Effects Processors and Condenser Microphones. Their gear is featured by 2 artists, with the strongest followings in Electronic, Rock, and Folk, World, & Country. Notable users include Elliott Smith and Andrew Bayer.