No code to post tonight because it's unfinished.
I'm converting all of STK to limbo, but not directly into signalfs. I'm creating a module that will contain all the sound sources, filters, and effects in the STK, with one ADT for each sound. This can then be used by signalfs to serve a file, which can be a combination of any of the ADTs, or by any other limbo app.
Rog has suggested an alternative application using the shell alphabet. I will try this once the library is written.
Rog pointed out how inefficient signalfs is in its current form. I agree; the performance is terrible, which makes it compleletly unusable for realtime sound support. This re-implementation will improve performance. But any hardcore DSP programmer is only likely to snicker at our attempt to implement DSP in limbo. At the end of the day I'm doing this to create a framework for ease of experimenting with DSP, not to create a sound system that will out perform all others. That is the tradeoff I make by writing this in limbo.
Another possible implementation is to create a C library module or device compiled into emu. This would perform well but be less malleable. I'd rather code in limbo.