6.1 using a cs1 or cs2 as rear?

[Lietuvis91]

A very perliminary idea... but:

I was thinking about getting an amp to power my center cs2 and for the money I find that I'm looking at getting a 2 ch amp, something like a parasound 1000a. Well, if I get another 2 ch amp, i might as well use the 2nd channel to power a rear speaker and was thiking about putting a cs1 or cs2 as a single rear ch. (I remember seeing in my marantz manual that it will support this kind of a 6.1 setup)

In my own head, I just cant see the difference between 7.1 and 6.1 being all that amazing, but what do i know...

anyone try this? were you happy with results?

[kuntasensei]

7.1 in the home only exists because putting a single speaker directly behind you can cause a psychoacoustic reversal wherein the rear center sounds like it's coming from in front of you. The solution was to put two speakers behind the listener so this psychoacoustic reversal doesn't occur, because then the sound always comes from multiple point sources. Another solution is to use DPL-IIx Music mode for 6.1 setups so that the sound is always spread between multiple speakers, eliminating the potential for psychoacoustic reversal from a single point source.

Fortunately, using a center channel speakers as a rear center does tend to work better than a bookshelf speaker because they use a D'appolito array configuration (i.e. midrange, tweeter, midrange). Still, if you're going to use a center channel for your rear surround, I highly suggest using DPL-IIx Music instead of EX processing to fill in the rear surround (and so does Dolby).

[Lietuvis91]

oh wow, that's very interesting, I was not aware of any of this. Thank you for chiming in!

Just thinking about this now, I realize that nothing out there is encoded to play in a 6.1 mode. Most movies are 5.1 or 7.1, correct? So this would mean that I couldn't just use direct playback like I currently do with my 5.1 setup, which sounds cool btw! And i find that when extra processing is involved things just don't sound quiet right, or maybe I was doing something wrong...

I have a friend who has a cs2. I think I will borrow it, and see how it sounds in the rear. That's probably the best way to find out, but now i'm thinking i should stay away from non-standard speaker configurations. In fact I should just probably stick to 5.1...

I would actually like to hear more on everyone's prefered processing selection for movie playback in their current systems. As I said, I typically use direct in my 5.1, because i think that's how the movie was encoded and intended to be watched.

[kuntasensei]

Actually, most modern digital soundtracks are encoded for 5.1EX in the theater, which means the center rear information is matrixed into the side surrounds. Using DPL-IIx Music Mode to extract that info works really well.

I'm running a 9.2 setup (4 surrounds and front height channels with a Buttkicker), so I run DPL-IIx Movie + DSX processing full time.

[gimpod]

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[Lietuvis91]

I ended up picking up the hca-1000a amp, so i think I will borrow the cs2 from my friend when the amp comes in and try the 6.1 mode with dpl-IIx music mode, like you suggested. Should be interesting. Thanks for your input!

[mdaudioguy]

7.1 in the home only exists because putting a single speaker directly behind you can cause a psychoacoustic reversal wherein the rear center sounds like it's coming from in front of you.
[...]
Still, if you're going to use a center channel for your rear surround, I highly suggest using DPL-IIx Music instead of EX processing to fill in the rear surround (and so does Dolby).

Hmmm, news to me, too. So, what's wrong with PLIIx Movie mode? Wouldn't that accomplish the same thing?

[kuntasensei]

Hmmm, news to me, too. So, what's wrong with PLIIx Movie mode? Wouldn't that accomplish the same thing?

You can't use DPL-IIx Movie with a 6.1 setup because of the psychoacoustic reversal issue. DPL-IIx Movie would steer things too hard to the center rear. DPL-IIx Music, however, leaves some of the rear center sound in the side surrounds so that you're getting both the sound from the rear center PLUS the phantom imaging from the side surrounds... hence no psychoacoustic reversal, because the sound is coming from multiple point sources. AVRs will typically not even let you select DPL-IIx Movie if you only have 6.1 hooked up for this very reason.

On a 7.1 setup with two rear surrounds, DPL-IIx Movie is basically set up so that it always steers using varying amounts of sound in more than one channel at a time, though not to the extent DPL-IIx Music mode does. In other words, for example, if you had a sound meant to be in the rear center on a 6.1 setup with DPL-IIx Music, that sound would essentially play 50% from the center rear and 25% from each side surround so that there's no perceived reversal. In a 6.1 setup using Dolby EX or DTS-ES, that sound would play 100% from the center rear, increasing the risk of perceived reversal (whereas this doesn't happen with EX in the theater because they're using multi-speaker arrays in the rear). In a 7.1 setup with DPL-IIx Movie, that sound would instead play 50% from each rear surround and not in the side surrounds at all, mimicking the multi-speaker arrays of movie theaters. Since it's coming from two point sources behind you, there's no perceived reversal and it still images precisely behind you. I'm simplifying here with these percentages... but you get the idea.

[Lietuvis91]

i just looked in the manual of my receiver and didn't see any DPL-IIx options. The Marantz 7002 is a slightly older model, so maybe it doesn't have that option. I did see Dolby EX and DTS-ES in the manual but no DPL-IIx.

looks like these will be my options if I go 6.1:

5.1ch + Pro Logic IIx Music
This mode provides 6.1 or 7.1 channel surround sound from 5.1 channel sources music soundtracks.


Pro Logic IIx MOVIE
This mode provides 6.1 or 7.1 channel surround sound from Dolby Surround, encoded stereo movie soundtracks.

DTS-ES (Discrete 6.1, Matrix 6.1)
DTS-ES adds the surround center channel audio to the DTS 5.1 channel format to improve the acoustic
positioning, and makes acoustic image movement more natural with the 6.1 channel reproduction.
This unit incorporates a DTS-ES-decoder, which can handle DTS-ES Discrete-encoded and DTS-ES Matrix-encoded program sources from DVD, etc. DTS-ES Discrete 6.1 features digital discrete recording of all channels, including the surround back channel(s), and higher quality audio reproduction. DTS-ES is not available in systems that do not have surround back speakers.

[kuntasensei]

BTW: DPL-IIx = Dolby Pro Logic IIx.

[Lietuvis91]

oh... so I should be good!

[pdxfj]

I am using a pair of bookshelf speakers for my back surrounds spaced about 6 feet apart. It is surprising how much they added to the openness of the back end. I'm also finding a number of movies that are encoded in DTS-HD-MA ES Matrix.

Even with using di-pole speakers as my surrounds, the addition of the back surrounds make a noticeable difference.

Some 5.1 tracks sound good in DPL-IIx and others do not.

As far as an amp, save for a 3 channel. Having one amp run you mains and center will sound better than just adding an amp for the center channel.

[Lietuvis91]

At this point I will have 2 amps:

parasound 1500a(205wpc) and 1000a(125wps x 2, or 400wpc x 1)

So I will have the front sound stage amped, and I purposely bought two parasound amps to make sure there is no amp colloring of the sound if the brands were not the same. I will see how this goes. The cs2 should sound nice with 400watts kicking it's butt!

As for the rear speakers. I really would love to do 7.1, but with the way my room is setup, a single wide speaker is actually perfect because I have a spelf to set it on at the perfect height. Even if I got 2 separate speakers, they would have to sit too close together and probably make it seem like there is no difference which one is producing the sound. This is my reasoning for trying 6.1 anyway...