For all those of you who have upgraded their systems to 5.1 surround sound and still have a bunch of media files that are using standard two channel stereo...there is a new directshow filter available from sourceforge.net that will port the stereo sound to all of your new, expensive and unused surround speakers. The URL for the free filter download is:

https://sourceforge.net/projects/matrix-mixer

It works well with Zoomplayer and MSP.