2.0 or 3.0 or 4.0 for HT Movie Audio?

>02-14-11: Dorfma05 writes:
I'm planning on doing a form of 4.0. I have the front left & right set up as full range with a sub on each of these 2 channels to enhance the bottom octave.

The problem there is that Dolby Digital is encoded to allow 105dB SPL from the screen channels and 115dB SPL from the LFE track. To avoid speaker damage from over-excursion and prevent clipping Dolby recommends entirely discarding the LFE channel when down-mixing in installations without sub-woofers.

Some processors make that configurable, some don't.

Thanks to everyone who has posted. Healthy feedback regarding the benefits (and limitations) of each configuration.
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- Byron: You said: "I am currently listening in 3.1, and it is a very close approximation of 5.1. In some ways, I prefer it to 5.1." Can you explain further?
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I was able to test a 2.0 downmix via PCM out from the bdp to my DAC with a few movies.

The center imaging is very stable and the timing matches the video lip movement. There are usually only two of us watching movies, so we are sitting in a very central position to the speakers.

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- Drew: I plan on bypassing processing (when I get the Oppo 95/93) by using the analog outputs of the bdp. Any issues doing it this way given your comments re processing?

To answer your question:

Without the sub I would just to 2.0. The sub is what makes home theater. With a sub I would take 4.0 over 3.0. For what it is worth I have done 2.0,2.1, 3.1, 5.2, 7.2... back to 2.0, over the years.

Now my current setup is a little different. I run to separate systems in the same room. My 5.1 (Polk RTi A3 x5, 550wi subs x2) is mounted to the ceiling. I used their Key hole mounts and made mounts out of 2X4s/plywood (wireless subs in the back of the room behind the theater chairs). The rest of my room is "optimized" for 2.0 (currently thiel CS2.4 etc) music. Each system has its own electronics and they do not intermix.

My own thoughts:

To me the most important thing is keeping all the speakers the same. I don't mean the same brand or line I mean the same speaker. Now if you have a big budget you can put two systems in the same room and make the surround sound almost unnoticeable .

Use 5 Thiel Power point speakers and a JL Audio in-wall sub. It would make a very nice looking and sounding system that could be in the same room as your two channel room.

Just a thought.

An update.

Still playing with 2.0 for movies and have been pleased with the results from two separate sets of speakers: the Vaughn Pinots and Gemme Tanto V2s. Need to get the Charios into rotation next.

Once I move some gear, I will make a final determination.

In the meantime, if other Audiogoners have some thoughts and their personal experiences to share, definitely post.

- David.

As noted in my 2/14 post, I'm using 5.1, but have found 4.1 just fine, given we sit at the apex of a near-field triangle. I've tried to match the voicing of the five channels by using speakers with the same model tweeter, and it seems successful. But I've been thinking of 7.1, and wonder if 6.1 might be the way to go. I'd use the speakers that now provide the center channel instead at the rear of the room. I have my doubts about how important it is to match the voicing of channels 6 & 7, but it couldn't hurt.

db