Did you look at synthesizer ? There is a short introductory file [1]. Cheers, Thu [1] http://hackage.haskell.org/packages/archive/synthesizer-core/0.2.1/doc/html/... Thanks for the tutorial link. As I'm new to Haskell, these 2 lines got me thinking: "Using plain lists is not very fast" and "Getting real-time performance is mostly an issue of the right signal data structure." What do you use as an efficient byte buffer in a value-oriented language? The array tutorial says "Obviously, a naive implementation of such an array semantics would be intolerably inefficient, either requiring a new copy of an array for each incremental redefinition, or taking linear time for array lookup; thus, serious attempts at using this approach employ sophisticated static analysis and clever run-time devices to avoid excessive copying."