Can a 3.1 system be acheived (really acheived)?

[dooher]

Greetings, I have an interesting problem: I have a situation where I can't easily get surrounds in place, and would be happy (enough) with a good 3.1 setup.

Setup: Rotel RSP-1069 + RMB-1095.

Now, I can setup my speaker section on the 1069 for L,R, C, and Sub, but will/can I actually get a true downmix to these channels without loss of information (e.g. setting surrounds to None redirects that data to the 3.1 channels)? Is this really possible? Or, is the Dolby Digital Downmix spec such that you can downmix to 2 channel stereo, but not some hybrid like 3.1?

Make sense?

[grit]

Good question, and I have NO idea what the answer is. The most logical answers would seem to be that the 2 rear channels get discarded or they are output through their respective front channels by the DSP.

To test the theory, I'd take a demo disc (or you can use the THX calibration found on several dvds/blurays) that plays sound through each channel. Then see if the rear left & right come out the front. This is assuming the output on the demo disc triggers Dolby or DTS decoding, and of course, you'd want to check each to be sure.

Please let us know what you find.

[madmac]

My experience is this. Play the amps and processors 'AS IF' there were surrounds operating. Dolby digital and DTS is a very specific and dedicated process. If you ask the processor to send the surround info to the left and right mains.......it will get messy. Your better off operating the system 'as if' there were surrounds. If you attempt to run the system as a 3ch only system with a sub, there is a possibility that the (LFE) low freq effects line in HT dolby digital signal might be lost!. That would be a major compromise!.

[Kevin D]

The Rotel will mix the rears into the fronts, however the processor will enable night-mode on Dolby Digital sources. This will severely limit the dynamic range.

I would suggest setting your sources up as stereo, and let the Rotel decode it out to 3.1, rather then running 5.1 folded into 3.1.

Kevin D.

[dooher]

Kevin D, I'm not sure I understand...if I specify a 2 channel stereo mode for the source input, I can still define the Center channel in speaker setup and the 1069 will/might decode the signal and utilize it (as long as I set the center to something other then None)?

[Kevin D]

Yes. Set your DVD/BR/CABLE/ETC to output stereo only. If they don't have an option to only output stereo, hook it up analog.

Set the Rotel to surround=none, center=small, main=small, sub=yes. Put the surround mode as Dolby PLII movie/music and it will derive center information and LFE from the stereo signal.

The reason for not using Dolby Digital is, per Dolby rules, if you run less then a 5.1 speaker configuration you run the risk of damaging speakers rolling two channels of sound into one.

Kevin D.

[Dmantis]

I suggest calling in a professional Installer. They will get the surround channel speakers in place as they do it each and every day. What area do you live in? I know many people in the field from around the country , I can probably suggest someone to go with.

To answer your question , I never been happy with a 3.1 system. In my years in this hobby I have had to wait a few times for my surround speakers but had the fronts , center and sub as you do. When I finally got the surrounds in place , to me it was night and day difference. I also watch a lot of action movies which take advantage of the surround speakers. I also listen to SACD and DVD AUDIO which also takes full advantage of those channels.
When you break it down , you are missing out on 30% of the experience. The surround channel speakers are very important and I feel equally as important as the rest of the system. I use the same exact speaker for my center as well as my rears for a perfect 360 deg sound field. My main channel speakers are also an exact match but are a tower design instead of a on wall design.
You can use a 3.1 system , I probably would rather go just 2 channel with a sub and leave the center out. Either way you are losing out.
If you can post a pic or 3 of your room , maybe I can suggest a way to get the rear channels in , Do you have a basement or attic above or below your room? Is the room carpet or hard wood flooring?

[madmac]

I still contend that you are doing something that the processor/receiver was not designed to do. Asking it to send surround info to the mains is REALLY not a good idea and will likely have marginal results. I still think you should trick the processor into thinking there are surrounds. Yes, you will lose that audio information but it is at best...surround effects. Another option is to get one of those 'all in one surround bars' that apparently 'simulate' a surround effect all from one speaker!!. Probably not that good and a compromise as well. Seriously...just run it as a 5.1 system without surrounds and be done with it. Maybe later you can find a way to incorporate surrounds.