How much would be lost if........

Do two seperate rooms.When you put a TV in the middle your system wont image properly.Thats why you need a center channel.I have been fortunate enough to do both.

I also have a 100in projection screen so I don't think that it will interfer with the imaging, sorry I forgot that.

Tireguy- I wouldn't recommend it. There is a significant step up for 5.1, and the center channel is important for holding dialog centered and for intelligibility. Not sure how you would get the surround L&R out w/o a pro-logic decoder and then the center channel info would be missing. The L&R have very little info on most pro-logic soundtracks. The center is not just a summed mono signal. In pro-logic, the surrounds are a limited bandwidth mono signal. In 5.1, they are full range, stereo. Also there is a dedicated LFE channel for subwoofer. Furthermore, I think you can get buy with a lower quality speaker for HT, since you are not critically listening to the soundtrack; the medium is primarily visual, after all. Just my $0.2.

I personally have never found a center channel speaker that I like and have never used one. I pefer it with out one. Dolby digital is of course better then dolby prologic but i have found that a great pro logic pre amp like the Lexicon cp-3 is much better then a cheap 5.1 decoder. There is so much more to sound quality then seperation.

I might restate your question. Instead of asking can I have a good HT without a CH, maybe it should be can I have a good two channel system with HT? In my experience the answer to both of these questions is yes, but it will cost you big bucks.

I unfortunately don't have the room for two systems so I had to combine. I have Magnepan 3.6's and don't use a center channel, but in order to do this properly you need a processor that can allow a phantom center with depth, volume, and placement adjustments. I went with the Meridian 568 and it works great, but I could probably get equally good sound with a lesser system in a seperate room.

The two channel stuff is more complicated. I needed to deal with the TV in the center (which you don't have), seperate power supplies for the TV, DVD, and processor, two channel preamp with theater loop etc. The simple answer is use two rooms, but you can do it all in one with some work.

Just to help a little I do have a preamp/surrond proccessor which can create a phantom center with several adjustments at all 5.1 speakers. However I have another question can I get independent surrounds with out a center, ie using a digital out on the DVD player the preamp automatically goes into dolby digital and I am unsure if I can run a 4.1 set up? Thanks for all of your help so far.

Why the sudden defense of 5.1? I thought HT was routinely trashed on this forum and previous threads concluded that center channel speakers were at best mediocre and arguably unnecessary. This, by the way, is the gospel as preached by Mr Levinson and Red Rose.

In response to how much is lost by not having a center...A friend of mine has a system with no center channel and is always complaining about the level of the dialog compared to the music and sound effects. DVDs that have a 2 channel mix usually work pretty well when decoded as pro-logic or stereo and you can hear the dialog at a reasonable level for the sound effects. DVDs that only have 5.1 mixes can be mixed down to 2 channel output by the player, but in most cases the dialog seems to be downmixed at too low a level such that when you play the movie so that you can hear the dialog through the front two channels ok, then when sound effects or music kicks in, its way too loud.

I couldn't imagine having a home theater setup without a center channel, I think that's one of the best improvements for home theater sound. Also when I come across a movie that doesn't have a 5.1 channel mix, I am really disappointed so I would say that there is a lot to miss without a center channel.

I think you can have a decent comporomise of two systems in the same room. In your case with the screen, you probably don't lose much in imaging for stereo either so you can probably do better than most people in mixing the two. Still, I think the center is essential for home theater.

My Meridian runs a 4.1 with phantom center. I don't know if other do, but I would imagine so. By the my experience is that 4.1 with independent controls for the phantom center are the only way it works. Panzercat is right about the problems with Dolby Surround.

I've tried it without the center and it did sound great, did not realize I was missing anything until I put a center in the mix. Center is a definite for serious HT. Not nessary if your not a big ht head. But the question I believe you asked was if you don't add a center will your pre still play 5.1 or in your case 4.1.. I will say yes to this, you should have the option of selecting a center speaker in the pre setup screen.
good luck..

I have the Avalon Arcus and a HT processor that does the phantom... I do not have problems with voice levels, positioning or inteligibility of the sounds. I have auditioned so many center channels that didn't work well with the system that I gave up.. I like my theatre as 4.1, and the only surround I would try is the one from Avalon. This may not work well, since it was designed for the Sentinel, but it will probably be the best match you will find. The other crazy thing that could be done is to see if you could find a 3rd Eclipse - this I know will work well... I borrowed a extra pair of Arcus for my theatre with a matching stereo amp for center and WOW!! The extra 11.5K and space requirements just was not worth it. If you REALLY want to do HT properly, it should be a separate room, separate components... IMHO Avalons do HT well enough not to worry about a separate system or a center