Why is 2 Channel better than multi-channel?


I hear that the music fidelity of a multi-channel AV Receiver/Integrated amp can never match the sounds produced by a 2 channel system. Can someone clearly explain why this is so?

I'm planning to upgrade my HT system to try and achieve the best of both worlds, I currently have a 3 channel amp driving my SL, SR, C and a 2 channel amp driving my L and R.
I have a Denon 3801 acting as my pre. Is there any Pre/Proc out there that can merge both worlds with out breaking my bank? Looking for recommendations on what my next logical steps should be? Thanks in advance.
springowl
I agree with the notion that not having identical speakers does somewhat diminish sound reproduction. I have experimented quite a bit with my settings and found a few things that I believe enhances multi-channel music. I use a B&K reference 30 pre/pro and previously owned a Denon 2802 receiver. The B&K gave me the ability to select specific channels with each listening mode(an option I never had with my Denon). Through trial and error, I learned that listening in 4 channel-mode(no center channel)improved the sound quality of music. I am assuming that this is simply due to the fact that the center channel speaker, a Paradigm Studio CC, doesn't quite match the Studio 80 front speakers. Furthermore, i noticed an audible difference when I set my rear speakers (Studio 40's) to "large" in the speaker setup menu. Since then, I always listen to music in 4 channel mode with all 4 speakers set at "large" and have been much happier with multi-channel reproduction.
Chucknms...In discrete multichannel recordings (SACD or DVD-A) the center channel carries sounds that are simply not there at all in the Left and Right channels. No amount of superb imaging can recover this information.

You really ought to take the time and trouble to get that center speaker set up right.
true...I should have been more specific and said multi-channel music, not necessarily 5.1 discrete as you mention. I would never recommend anyone not include the center channel for SACD or DVD-A playback.
A center channel is not a full range speaker, so, naturally, it would only be fittign to use one in prologic surround theaters.
We all have a pair of ears which has 48 auditory canals, looks like the industry is trying its best to reach the ultimate goal of offering 40.8 channel HT system, I will wait for that patiently. Until then, I will continue to use the 48 auditory canals in my ears to create the surround sound effect from the 2 ch system.