He studied double bass and composition at the Conservatorium van Amsterdam and at the Cologne University of Music.
Gramss released more than 25 CDs under his name. He’s been an inspiring and innovative presence in the world of jazz with his band UNDERKARL for the past 25 years, and recently with his new trios SLOWFOX (with Hayden Chisholm & Philip Zoubek) and FOSSILE 3 (with Rudi Mahall & Etienne Nillesen).
His bass activities include his solo works (Atopie), a long term bass duo series (started with Stefano Scodanibbio in 2008, and continued with Barre Phillips, Tetsu Saitoh, Mark Dresser, Barry Guy, William Parker and Joëlle Lénadre in over 50 concerts + recordings), several quartets and the international double bass orchestra BASSMASSE with 13 (and up to 50) bass players.
Gramss has composed for radio drama, movies and theatre and – among others – for choreographer Pina Bausch, and recently with/for the Ensemble Modern.
He teaches at the Cologne University of Music and University of Osnabrück, and gives master classes around the world. Extensive touring with his music has led him to venues and festivals all over the world, including Japan, India, Latin America, Russia, USA, Africa, and Australia.
He was the co-creator and the curator/ director of SAMUR (South Asian Music Residency) in India in 2016 and 2017.
International cooperations: Marilyn Crispell, Fred Frith, Sidsel Endresen, A. v. Schlippenbach, Tom Cora, Ensemble Modern, N. Wogram, E. Sharp, P. Kowald, Z. Parkins, Brötzmann, J. Tilbury, Conny Bauer…