well if you don't have at least 4 speakers (left, right, rear left, rear right), you aren't gonna enjoy it too much.
ah I forgot to say something important
The 5.1 module NEEDS bigger buffers! The buffer size counts in total samples from all channels at once, so with this one being 5.1 (6 channels) the buffer "duration" is 1/3 of the others! I would recommend making it 4x bigger while using it.