You can install safely two drives without problems. Usually the operative system is installed in the master drive, but you can store any data you like on the slave drive and there is no problem in reading data from the slave drive.
You can listen any song from the slave drive providing that you have a software to play these songs.
The only thing that could not allow you to listen a song or watch a movie is a missing codec. For example, if you don't have a mp3 codec installed on your operative system, you can't listen any mp3 file, both from the master or the slave drive.
I hope to have answered enough clearly