Requisite Audio Engineering is a boutique American manufacturer of high-end, all-tube outboard studio equipment founded in 1995 by Danny "Sage" McKinney, a former professional musician who turned to designing audio gear full-time. McKinney has cited Standel founder Bob Crooks as a primary mentor, and he also owns Standel Amplifiers and co-owns the RAAL-Requisite headphone venture with Serbian ribbon-driver maker RAAL.

The company is known for point-to-point hand-wired construction, tube rectification, audio-frequency chokes, polypropylene and oil capacitors, and the avoidance of electrolytic capacitors in the signal path. Its core product line includes the Y7 tube microphone preamplifier, the L1 optical limiter, the PAL and PAL Plus MkIII (which combine preamp and optical limiter in a single chassis), and the L2M mastering limiter/expander, the last of which features a Response Curve control that adjusts the frequency band where compression begins. The gear is aimed at recording, mixing, and mastering engineers seeking vintage-style tube signal processing with audiophile-grade parts quality.

Requisite Audio has 2 products cataloged on Equipboard, including Condenser Microphones and Effects Processors. Their gear is featured by 2 artists, with the strongest followings in Rock and Folk, World, & Country. Notable users include Neil Citron and Alison Krauss.