This information is not yet completed. For the time being, you may want to check out the C++ CMixer classes written by Sam Blackburn which can simplify using the Mixer API.

Also, you may want to go to DejaNews and do a search for a message written by Sean Dynan (sdynan@cccgroup.co.uk) in the comp.os.ms-windows.programmer.multimedia newsgroup entitled Re: Audio mixer example code.