rear speakers disabled with 5.1 coded DVD's (1 Viewer)

[JR1]

My theater is wired for 7.1 - 2 fronts, 1 center, 2 sides, 2 rears and a subwoofer. I have a Yamaha RX-V861 reciever. When I play movies in Dolby Digital 5.1, the rear speakers are deactivated - the surround only comes from the sides. For Dolby EX and DTS ES, the rears are activated (because these are 6.1 formats, I assume). Is there any way to "trick" the reciever into decoding 5.1 by using the combination of a side and rear to equal 1 channel?
The system sounds good as is, but I think it would be much better if the rear speakers were active. I've tried playing around with all the sound field programs with no luck.

Most movies, even HD and bluray are still being released in 5.1, which I don't understand. Does anyone know when movies with Dolby HD or other 7.1 formats will become available?

Thanks

Jim

 

[Ben-S]

If your receiver has a Dolby Prologic 2x setting (DolbyPLIIX) use that rather than Dolby Digital. Just make sure that your surround back speakers are turned on. You will then get sound out of all of your speakers.

 

[Bob_L]

IMO, the 6.1 and 7.1 format/decoders have proven to be the industry's latest "quadraphonic;" that is, an "innovation" intended to help sell a new generation of hardware but which has proven to be less useful/accepted than they hoped. In short, 7.1 (and I'm wired for it) is overrated and unnecessary.

As Ben wrote, enable Dolby IIx on your Yammy and it will throw audio at those rear speakers, although I almost invariably prefer the original 5.1 mix in my setup. For those who don't have IIx, there are some other 7.1 simulators, too, such as the one that was on my Outlaw 950 pre/pro, so you might have the ability to simulate 7.1.

Most films are still mixed in 5.1 and I don't think that will change in the near future.

 

[Jeff O.]

Jim,
I don't know how it works on the 861, but on the remote for my RX-V2400 there is an EX/ES button. This button will activate the rear back speakers and the amp will matrix a rear back signal on DD and DTS 5.1 sources.

 

[JohnRice]

I'm not up on all the latest surround systems, but by using Ben's suggestion of DPL2x, aren't you completely tossing out discrete channels in order to just have "sound" coming from the rears? If so, isn't that kind of like taking three steps back in order to take one forward?

 

[LanceJ]

I agree with all this.

IMO 6.1/7.1 is only useful if for some reason you have to place regular surround channels verrrry far apart, causing a sonic "hole" behind you - then the extra (back) surrounds can help fill that in.*

The extra channels also probably have the potential to lessen the quality of the rest of the receiver: since competition is getting so intense now for consumers' audio dollars, the quality of something else in the receiver may be being sacrificed to cram in those two extra channels, along with the processor chip that generates the back surround signals.


* I don't use the standard Dolby-recommended surround placement, instead I use the ITU configuration designed for surround music playback & so have my surrounds to the side but *behind* me (instead of to the sides), by about four feet. Sounds much better to me, literally much more of a surrounded feeling.

 

[LanceJ]

The processor chip looks at the info in the 5.1 signal's rear channels, figures out what is supposed to be occurring in between the two surrounds (when set up in an actual room), pulls that information out and sends it to the back surround channels(s).* It is deleted from the surround channels, which are now the side surround channels.

AFAIK this is a form of matrixed signal, which can result in rather "blurry" channel information being produced, reducing the discreteness of the original signal, another reason I'm not much of a fan of that format.

* I'm assuming the back surrounds in a 7.1 system receive a stereo version of that extracted signal

 

[RayJr]

JR1,
If I were you I would just keep DPL2x on when ever you listen to a 5.1 movie...it should work fine for you. DPL2X does a very good job of steering your surround content and not making it sound funny. I personally also have a 7 channel surround but mainly use the "other" 7 channel processing (Lexicon Logic 7) and I can tell you from listening to movies this way for at least 8 years..that it really surrounds you in a bubble of sound.

Later
RayJr

 

[Jeff O.]

John,
I don't know about DPL2X mode, but I know that using the ES/EX mode I described above it stays in DD and just gives you a matrix signal in the surroung back derived from the surrounds as LanceJ describes in his post.

 

[JohnRice]

And I thought all 7.1 receivers had that feature, so I didn't understand the DPL suggestion.