Hello, Sorry I made a mistake in my previous email: although and not althought!!!! Programming CSound. I am also trying to built some stupid opcodes (stolen Hidden Markov models and a Chebichev filter). You can find explanation in the help file: *How to add your own opcodes*. But it is not really straight foward. The source is available on the "dream" CSound ftps as AllCSound.zip. Maybe it is because I do not have Visual C++ or Code Warrior, I do not have all the *.h files that are required to compile. I have spent ages trying to find them on the internet but even of they have the same name, they do not have the same contents. => Where could I find ALL the required files (libraries...)? => I said the source was in AllCSound.zip but I do not find the early opcodes for instance. Are they somewhere in one of the files? I hope you'll be more lucky than me. But I do not give up !!! Olivier Pasquet. -------------------- Olivier PASQUET -- APU -- Music Faculty OP101@mercury.anglia.ac.uk www.sinclair.anglia.ac.uk/~op101.student.cambridge.anglia