I got a C++ example of a project using the mixer API at the Code Project site. Its at www.codeproject.com

If I knew how to attach the zip file I would send it directly to you as I have already downloaded it. It's called 'msmixer.zip' and its an imporived and commented version of the version provided by microsoft which I guess is pretty hard to make sense of.

Its a good start in any case. I also found an excellent description of how the mixer works on the web and I copied the stuff to a word document. It has all that junk about Lines, SOurces, Destinations, etc. Don't remeber where I got it but it might also be the code project.