well, xbox360 support Dolby 5.1 by optical output only. the analog will have dolby surround for 2.1 setup.

so, if possible, get a speaker set with optical input support for 5.1. exp like klipsch DMX5.1D, logitech z680 or z5500.

for speaker like edifier R501, it's only a speaker set with amp and doent have dolby decoder built in. so u cant connect ur xbox360 to have 5.1 srround sound. cuz this type of speaker need a computer soundcard that support analog 5.1 output (with 3 deferent connector, green, balck and orange) cuz the surround sound is decode by the soundcard it self and outpu it to deferent position's satelit speaker. unless u get an external soundcard or decoder unit like creative extigy or DDTS-100.

or u may try to look for creative inspire GD580 as well if wanna cuz cost. it should be about RM800. i saw it early this ear at lowyat.

hope u guys understand what am i talking about... kindergarden standard english... pay sey~~~~