Koen Holtkamp has been played on NTS in shows including Golden Ratio Frequencies w/ AHRKH, featured first on 14 June 2015. Songs played include Night Swimmer, Between Visible Things and Keep It.

Koen Holtkamp has released two solo albums as Aero and two albums as Mountains, a duo project with Brendon Anderegg. He has toured throughout the US and Europe performing everywhere from festivals, art galleries, and museums to basements, hippie communes, churches, and rock clubs. Holtkamp has performed with Fennesz, Tony Conrad, Greg Davis, Minamo, Tape, Nicholas Collins, Carsten Nicolai, Lichens, Supersilent, Alog, etc. He has also been included in several exhibitions, most notably at the Centre Pompidou in Paris. His current solo performances utilize acoustic instruments and objects played through a series of both analogue and digital electronics to create an extremely gradual yet melodic listening experience. Field Rituals, his first solo album under his own name, is released by UK based Type records in 2008.