Is there anyway to use speaker set without main speaker?

i bought insignia NS-5648 a year ago or so, its 5.1 set, but my problem is that when i moved to different location, and i left few things behind, and seems like i forgot the main speaker that has the controls like volume and on/off switch, and i remember i putted in the bag but i cant find it anywhere. So my question is, is there anyway to use my speaker set without that main speaker? I've tried plugging iPod and it didn't work. Any suggestions? Thanks!