|The Realtek speaker test is programmed to play a sound through each speaker in turn to confirm that you've connected your speakers properly and that they are working.|
However, when playing music, you'll only get sound to all speakers (5.1 surround sound) if the source music was recorded in 5.1 surround sound. So if the music you are playing was only recorded in stereo (2 channels), you'll only get stereo output (nothing through the rear speakers).
You can't expect to get surround sound from a two-channel stereo or single-channel mono recording.
message edited by phil22