...the flautist masters an apparently inexhaustible repertoire of possibilities to lure a rich spectrum of tones and other sounds out of his instrument... .........................Aargauer Zeitung

 Refreshing experiments from Bach to Glass ...Keller, ... moves within the musical Intertext . Somewhere, between baroque and minimal music, between Johann Sebastian Bach Bach and Philipp Glass, he finds a piece that extends, first as an homage, then as variation, an interpretation of the theme - this in free variation - eventually (nearly) denying. He starts with Bach's "Bourée" and gradually moulds the piece into a form of blues. Then elswhere, the blues is not a real one, therefore "Don't Blues"... ...supportet by the technical equipment, the contrabassflute mutates into a percussion instrument trough the closing of the keys. ...................................................................Neue Zuger Zeitung

 ... In Shun-San for flute solo by Kazuo Fukushima, Keller proved, what an enormous variety of tones and sounds can be obtained from a flute. .............................................................................Badener Tagblatt

 Stefan Keller lead on a spirituel world trip with his own composition. While our senses floated high above the plains of South Africa, the flautist used his instrument as jungle drums. We heard sounds which seemed to come from another world: Hissing, snorting, three ore more tones together, singing and playing. A true firework of unknown but fascinating sounds which filled in the church beautifully. ............................................................................................ Wohler Anzeiger