Placid Audio is a custom microphone manufacturer based in Dallas, Texas, founded in 2003 by bass player and engineer Mark Pirro (Tripping Daisy, The Polyphonic Spree). The company began as a small-batch operation built around Pirro's first prototype, the Copperphone — a lo-fi dynamic microphone designed to evoke the sound of vintage broadcast and telephone-era recordings.

The brand is best known for its hand-built effect microphones aimed at producers, engineers, and recording artists looking for character-driven, distressed tones without resorting to plug-ins. Its product line includes the original Copperphone, the smaller Copperphone Mini, the omnidirectional Copperphone AV20, the Carbonphone and Carbonphone RU-80, and the Resonator A and Resonator B models. Each microphone is assembled by hand in Dallas and shipped with a lifetime warranty.

Placid Audio occupies a niche corner of the studio microphone market, with its mics frequently used as parallel or send options for vocals, drums, and instrument tracks where a telephone, AM-radio, or megaphone-style coloration is desired.

Placid Audio has 6 products cataloged on Equipboard, including Dynamic Microphones and Condenser Microphones. Their gear is featured by 8 artists, with the strongest followings in Rock, Pop, and Funk / Soul. Notable users include Jack White, Alex Lifeson, and Peter Buck.