Circa Alto is a project from Copenhagen-based atist Mathias Lystbæk, who is a composer and multi-instrumentalist. He has released music through labels such as Fluid Audio/Facture, ROHS!, Slowtone Collages, Phncrs, Adventurous Music and his own label, A Quiet Room Recording. He previously released a digital-only EP for Whitelabrecs called 'Floatings' as 'This Floating World'. He is also a part of the EQS Ensemble and MM Works, as well as collaborating with Japanese musician K Nogami on Fluid Audio.

Mathias grew up in a musical home, learning guitar and drums from an early age before learning to play other instruments such as flute, clarinet, piano and cello. His approach to composition draws its inspiration from other artforms, such as paintings, graphics, movies and installations.