This is now not the case, and as a result Ed FM can be used successfully with just a single sound card and the relevant drivers. However, there are a couple of drawbacks, the main one being that the volume of each player cannot be controlled individually. As a result, segues can sometimes sound wrong, especially if the "start next" point of a track is set too early. Not withstanding that, you need to do the following to make Ed FM work with a single sound card: