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Discussion Starter · #1 ·
I am about to build my rear and surround speakers, and was wondering if it is worth going to a full 7.1 setup over a 5.1? I have the room and the funds.


I watch Blu-Rays with my PS3 and send linear PCM to the receiver. I also have a Directv, Xbox360, and Wii.


I'm asking because I have seldom had the instance in which I believe I would have had all 7.1 speakers driven by my sources. For Blu-Rays, I recall only 2 movies or so that had 7.1 as an option. The other sources I have are almost always 5.1 channel. I dislike the thought of two speakers sitting idle. With linear PCM, which I have to use with the PS3, specific channels are sent to the receiver, so the 2 other channels would sit idle, right? As for the other sources (let's say Dolby 5.1 from the Directv), I assume I'd have to select some special processing option to make the other two speakers have any sound, right, or does the Denon automatically do something so that they are working as well?


I'm just confused. Seems like if I had them, they'd never work unless I select 7 channel stereo or something like that, which I wouldn't prefer...


Thanks,


MP
 

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There's probably some debate around here from people with 7.1 setups whether it's "worth it" -- as far as if the speakers are used "enough" or if they hear much of a difference over 5.1. The majority probably like it though. I'm getting ready to add a single back speaker for 6.1 soon (all I have room for) after wondering for a while if it would be "worth it."
I made the decision after reading posts here, as well as correctly understanding what processing modes would utilize the speaker(s), and how. Which is what you asked about...


As another very knowledgeable poster always points out here, systems have always been available with more speakers than the number of source channels (7(.1?) was around 20+ years ago), so don't worry about that. On 6.1/7.1 Blu-rays, you're obviously set with discrete channels. And on anything less (5.1, 2.0 stereo, etc.) the simplest way to sum it up is: you'd use "Pro Logic IIx" mode for everything (Movie mode obviously most of the time (Denon calls it PLII(x) Cinema), as you would for 2 channel stuff now).


For 2 channel sources, you can choose either PLIIx to use the side+back speakers or PLII (no x) to use only side surrounds (idle backs).


For 5.1 from DirecTV, Xbox, etc., you would apply PLIIx processing (probably displayed as "Dolby D + PLIIx C") to use the back speakers. For 5.1 from the PS3 over PCM, same thing (displayed like "Multi Ch + PLIIx C"). For 6.1/7.1 discs that the PS3 decodes, it would just show "Multi Ch In 7.1" or such.


When applying PLIIx processing to 5.1, the only thing it's doing is sending sounds to the back speakers that are the "same" in the surround channels, e.g. things that should image in the rear. "EX" processing (another choice you can cycle through) does the same, except it only generates a mono back channel (instead of PLIIx stereo), and sends that mono channel to both rear speakers. But you really want to stick with PLIIx with 2 back speakers, even if you're watching a "Dolby Digital EX" DVD, for example (PLIIx works better than EX decoding!
). Now people with 6.1, like I'll have, only have the EX choice instead of PLIIx Movie (Cinema) as the rear can only be mono.


Finally, with 1 or 2 back speakers, the PLIIx Music mode is available ("... + PLIIx M" on Denon). The difference between it and EX/PLIIx Movie (Cinema) is that the sound sent to the back speakers does not get canceled/removed from the side speakers. Not necessarily related to music playback, but it could be used if you find too much sound "collapses" to the back, or you just want more envelopment from the sides, etc.


Hope that helps. You certainly don't need 7 channel stereo!
 

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Discussion Starter · #3 ·
So you are saying that I can apply processing to a LPCM input signal? If so, that answers it all. I was thinking that when Linear PCM was used, the channels that were not provided would have to result in idle speakers.
 

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Yep, definitely.
I think there were some cheaper Onkyos a couple years ago that couldn't apply post-processing (PLIIx, etc.) to multi-channel PCM, but your 3808 can do anything and everything.
(I have the 1909.) This can be seen on the chart on page 77 of the 3808 manual.
 

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Discussion Starter · #5 ·
Thanks. I believe most of my confusion was resulting from the fact that since I do not currently have surrounds, the Denon has their output set to off. As a result, those post processing options were not available since the Denon had nothing to post process to. I have since told the Denon that surrounds were present, and viola, there are the options. Sweet.
 

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I did a lot of work, pulling wires, etc., to add to my 5.1 setup to get to 7.1. My humble opinion is that while I do use all 7 speakers, the work and cost was not worth it. I have an average size room. Maybe in a bigger room my opinion would change. At the same time I'm not pulling the speakers out any time soon either.
 
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