Is it possible to get 7.1 sound from a 5.1 soundtrack? I have speakers configured for 7.1 but no sound from 2 of them when playing movies with 5.1 sound tracks. Do I have to play a movie with 7.1 soundtrack?

Depends upon what type of processing you have.

I use a Lexicon pre/pro, and I can get 7.1 from a 5.1 soundtrack as well as get 7.1 from a 2 channel soundtrack with the employment of Logic 7 processing.

Most use DPLIIx for 7.1

It would be helpful if you provide info in regard to what receiver/pre-pro you use, what DVD player, speakers and how it's all interconnected.

Then... which speakers do not seem to produce any sound (sides/rears?).

As Ratman said, use DPLIIx.

Most use DPLIIx for 7.1

It would be helpful if you provide info in regard to what receiver/pre-pro you use, what DVD player, speakers and how it's all interconnected.

Then... which speakers do not seem to produce any sound (sides/rears?).

Thanks. I thought perhaps I was overthinking all this configuration stuff and that it just wasn't possible without a 7.1 soundtrack.

I'll crawl behind the AVR (take notes) and repost.

Appreciate the help.

I'm soooo behind the times. I don't even know what DPLIIx is. Glad you got some good info here, Magoo.

I don't even know what DPLIIx is.
http://www.dolby.com/consumer/technology/prologic_IIx.html

http://www.dolby.com/consumer/technology/prologic_IIx.html

An excerpt from the link: "Pro Logic IIx is the first and only technology to expand any existing stereo- or 5.1-channel audio for a 6.1- or 7.1- channel playback".

Is that really true? I thought Logic 7 was around way before Pro Logic IIx and it's definitely not the only technology to expand stereo or 5.1 to 7.1.

----your local nit picker...:p

Yes... your Lexi was innovative and provided Logic7 successfully well before Dolby Labs' DPLIIx was "mainstream".

Maybe you can take them to court on their deceptive marketing. ;)

How does Logic7 work, btw? How are the rear channels derived?

http://www.lexicon.com/logic7/index.asp

Probably the same way Dolby does it... :)
Just can't call it Dolby.

How does Logic7 work, btw? How are the rear channels derived?

Proprietary matrix algorithms. Lex kinda keeps that close to the belt.

http://www.lexicon.com/logic7/index.asp

Probably the same way Dolby does it... :)
Just can't call it Dolby.

Being that Logic 7 came out first, it's probably more accurate to say that Dolby does it like like Logic 7. Ya just can't call it Logic 7.;)

All kidding aside though, I doubt that the two algorithms are the same.

http://www.lexicon.com/logic7/index.aspThat link makes it sound as if it is mainly an encoding technology but that Logic7 decoding can also be applied to standard 2-channel recordings. But it says nothing about applying it to 5 channel recordings such as DD5.1. I presume it CAN be applied to DD5.1 material. Is it applied post-DD5.1 decoding?

Are Logic7 recordings available?

5.1 Logic 7 description taken from my MC1 manual:

"5.1 Logic 7 combines all the features of DD5.1 and DTS with enhancements by Lexicon and LucasFilm. This effect uses Logic 7 matrix technology to enhance the steering between the side speakers and the rear speakers, so sounds intended to come from behind the listener actually do come from behind. This effect also includes the adaptive decorrelation and re-equalizer features of THX 5.1"

The following 7.1 parameters are fully adjustable when used with DD 5.1 or DTS:
DRC---Auto, on or off
Vocal Enhance----off, +3db, +6db
Re-eq----on or off
Bass Enhance---on or off
Rear Delay Offset----0-20ms
Side Level-----Off, -30db to +05db
Rear Level-----same as above
LFE Mix Level-----10db to 0
Subwoofer Level----Off, -30db t0 +5db

When used with PCM (non DD processing) the following parameters are fully adjustable on top of overall system calibrations:
Auto Azimuth----on or off
Soundstage-----Front, neutral, rear
5 Speaker Enhance-----on or off
Surround Rolloff------453hz to 20.0kHz
plus all of the parameters listed above in the DD5.1/DTS description



The speaker levels are on top of the calibrated overall system levels.

I assume that logic 7 is applied post 5.1. Not totally sure though. Also, don't know about Logic 7 recordings. Never checked them out. Hope I didn't give ya more than ya wanted to know here.

That link makes it sound as if it is mainly an encoding technology but that Logic7 decoding can also be applied to standard 2-channel recordings. But it says nothing about applying it to 5 channel recordings such as DD5.1. I presume it CAN be applied to DD5.1 material. Is it applied post-DD5.1 decoding?

Are Logic7 recordings available?

You're one sharp cookie. I was just gonna type that question. Then I thought, lets read down and lo and behold, sivadselim asked it first. ;)

Most use DPLIIx for 7.1

It would be helpful if you provide info in regard to what receiver/pre-pro you use, what DVD player, speakers and how it's all interconnected.

Then... which speakers do not seem to produce any sound (sides/rears?).

Sony 52XBR4
SA Explorer 8240HD DVR (Cox)
Denon 1908 AVR
Sony 300 BRP
Bose A10 Speakers (don't laugh - they were a deal breaker with my wife to sign off on everything else ;) - they sound fine for now and I can always move them into a different room later!)

Soooo- being encouraged knowing I should hear 7.1, I set about to wire the back of my Denon 1908 (I forgot I had disconnected the Side Surrounds the last time I wired), set the amp assign feature for 7.1 (finally understood what that was all about), ran the Audyssey program (all positions) and now have all speakers working. Thanks for the replies.

One last question, should I normally keep the Input Mode for the Blu-Ray set to Auto? The manual says to set to DTS or PCM only when playing those signals.

One last question, should I normally keep the Input Mode for the Blu-Ray set to Auto? The manual says to set to DTS or PCM only when playing those signals.Yes. The auto setting means the AVR will accept whatever format the player sends whereas the PCM or DTS settings will only give you sound when the player sends that one particular format.