i have those, yes they do jam, well in fact. but if you want more jam at still good price, look for logitech 5300e.
on the x-530 the bass can be strong, do not under-estimate the wattage, i will say that now. also make sure you have a decent soundcard at least. with proper settings they do go far, i push them hard for as much bass as possible without (too much) distortion. so for the size and wattage consideration, put sub at max, and put the windows bass setting at 70%, and the wave at 100% and the master volume at 80% for gaming. for movies put the master volume at 100% because it does not rely on wave volume to add distortion.