Les Protorythmiques was originally intended to be presented by Luc Ferrari and erikM at the Musique Action Festival, which took place in France in May of 2005. Sadly, due to Luc Ferrari's deteriorating health, the collaboration never came about. Instead, Thomas Lehn was invited to perform the piece at the festival alongside erikM.

erikM, an improviser know for manipulating found sounds and recorded medium as a part of the group MIMEO, had worked with Ferrari on this roughly thirty minute piece of found sounds and musique concrete. The concept of the work is described rather ambiguously in the liner notes as an "open working process in which sounds and compositional parts could be substituted and transformed in an almost improvisational setting".

Thomas Lehn's role seems to be the grounding force here; his analog synth sounds provide a warm background to the sometimes harsh found sounds and manipulated, stuttering spoken word. The piece starts off with a few minutes of hyperactive musique Concrete, which is splintered and seemingly lacking in direction. A few minutes later, the piece slows down a bit, then some vocals, spoken in French, enter the mix. The synths enter the forefront, and the musique concrete elements become subtle, and sympathetic to the sound palette. The middle part of the piece is enjoyable; the found sounds, which include birds and a closing door, (played backward) among other less easily identified noises are used with restraint and grace.

Unfortunately the flow is interrupted now and again by chopped-up vocals and noisy detours, which feel out of character within the context of the piece. Les Protorythmiques definitely has its moments, but it seems that the improvisers got a bit too overly excited at times, and a result it feels like an incomplete work.