M-Audio's LX4 2.1 System and LX4 5.1 Expander System are two products that you put together to create a 5.1-channel set. At a combined price of $550 (as of January 17, 2006), they're expensive--and they're not targeted at PC users, either. Since the LX4 system is designed for use in audio production, you likely won't find it in many mainstream electronics stores. The system delivers a flat response across the frequency spectrum, so the person mixing can be sure he or she has an accurate rendition of the original source material with a neutral EQ setting..



Link: PC World