PSI Audio is a Swiss manufacturer of professional active studio monitors and active bass traps, based in Yverdon-les-Bains. The company traces its origins to 1977, when engineer Alain Roux founded Roux Electroacoustique after developing loudspeakers while studying at EPFL in Lausanne. The company was reorganized as Relec SA in 1988, and from 1992 to 2003 worked in close partnership with Studer, developing and producing the OEM Studer A1, A3, and A5 monitors. The PSI Audio brand itself was launched in 2004, following the end of the Studer collaboration.

PSI Audio's monitor lineup includes the compact A14-M and A17-M, the mid-field A21-M, the three-way A23-M and A25-M, the A226-MAIN main monitor, the A215-M mastering monitor, and the A214-M center speaker, supported by the Sub A125-M, Sub A225-M, and Sub A326 D-REX subwoofers. All products are handmade in Switzerland, with components individually measured and matched to tight tolerances. The company also produces the Héritage3 hi-fi speaker.

In 2016, PSI Audio introduced the AVAA C20, an analog active bass absorber designed to reduce low-frequency room modes between roughly 15 and 160 Hz without physical porous treatment. The fully digital AVAA C214 followed in 2023. The monitors and bass traps are used in mixing, mastering, broadcast, and immersive audio facilities internationally.

PSI Audio has 12 products cataloged on Equipboard, including Active & Passive Monitors, Acoustical Treatments, and Studio Subwoofers. Their gear is featured by 6 artists, with the strongest followings in Electronic and Pop. Notable users include Funkin Matt, Sander Van Doorn, and Afrojack.