I have asked this question before, but, to be honest, I'm still a little unclear. The bottom line is that I don't always know which surround mode to use in various situation.

I use my 990 for DVDs and for my Comcast cable box - I have it set to Dolby Digital for both situations. Lastly, I use it to listen to CDs (not SACD or DVD-A yet) and it is set to Stereo for this.

I just read the 990 manual again and I see that if my DVD has Dolby EX (is the audio format always listed on the back of the DVD case or in the setup menu?), then I should set it to that to take advantage of the rear audio. I see that I should play around with Bypass or Upsample and compare them to Stereo (which I have done before with no concrete conclusions). My DVD player is a Denon 1920 - I believe Gonk has said previously that he didn't think the 1920 would have a better DAC than the 990 - I think he's right as I liked the Stereo sound more than the Bypass, I think. That is why I'm using Stereo and not Bypass, but I have not played with Upsample extensively...

Any advice regarding playback modes, especially for DVDs and Cable, would be greatly appreciated.

Thanks

To a significant degree, it comes down to a matter of preference, but I can offer a few suggestions to try.

For DVD and cable, I'd try Pro Logic IIx Movie - it can be used alone with analog or PCM sources and overlayed on top of Dolby Digital sources to give you 7.1 from both two channel (Dolby 2.0 or PCM) and Dolby 5.1. If the disc is flagged for Dolby EX, it'll force EX mode automatically - while the EX discs that aren't flagged (and there are a good number of them around) will work just as well with PLIIx as with EX.

For CD's, I'd definitely spend a little time with upsample.

Clearly as gonk wrote:

it comes down to a matter of preference

I have found that 5 ch stereo or 7 ch stereo (depending on what you have in your room) somtimes sounds better than other modes for sources such as satellite or TV signal feeding 990.

Let your ears judge for you

hi everyone:

now I am a bit confused. how do you use prologic IIx movie over 5.1 dd?

When I am watching a DD movie, I can only set it to Dolby digital or wide Dolby digital.

Regarding stereo. Personally I like upsample. Works great.

Regarding DACs. You cannot compare bypass to stereo, if you want to compare the DACs, you have to take analog stereo out of your dvd player to cd input and compare that to when you send the digital input.

I have another question: whats the difference between pcm and normal? I was under the impression that Pcm down converts everything to 2 channel.

thanks

billy

Do you have surround back speakers, or do you just have the traditional 5.1 setup? You must have surround back speakers (7.1) in order to use Pro Logic IIx with Dolby Digital 5.1.

PCM is just a data format. It's the format that is used to store data on CD's, and it can be used with DVD's in some cases. DVD players typically allow you the option of configuring the digital output to provide either PCM (which, as you say, forces the player to decode and downmix any surround soundtracks) or a bitstream taken straight from the disc (which simply sends whatever audio data is on the disc, whether it is Dolby Digital, DTS, or PCM).

I do not have sourround back speakers because My seat is stuck to the back wall. I can put flat speakers on the back wall or hand the speakers really high up/. What do you think?

Let me know

billy

If you don't have a 7.1 (meaning rear surrounds) then PLIIx is a moot point. PLIIx esentially creates a phantom signal for the rear surrounds.

I've not tried it myself (always been able to keep at least five or six feet between my sitting position and the back wall), but I've heard folks recommend against trying to set up surround back channel(s) when the sitting position is flush to the wall like that. That doesn't mean it's impossible - it's certainly been done, and I've even heard of folks setting bookshelf speakers on the floor behind the couch so that they fire up along the wall. Others who have tried things like this may be able to offer better first-hand suggestions.

Hey does it make a difference to have a 7.1 setup compared to a 5.1. Does the HT experience get that much better. Gonk you have me an Idea that might just work. I would mount my speakers on the cealing and have them fire on the back wall.

Having 7.1 instead of 5.1 can provide a smoother and more enveloping surround field, but the danger associated with having the surround back speakers too close to the sitting position is not being able to balance the surrounds and surround backs - the back speakers can easily end up overloading the side surrounds, which can end up being perceived as a collapsing surround field. If anything, you might be better off with dipoles on the back wall for the surround backs so that the speakers aren't firing straight at you.

Thanks for the Advice, I curently have Klipsch S2 surround speakers that are hanking on the side walls. They have two horns and a woffer. they are Klipsch's Wide Dispersion Surround Technology. they are supposed to make you feel as if you have both rear and side speakers.

They are not bad at what they do depending on you sitting position.

when watching Comcast cable does anyone know if their signal is in stereo?

The 990 can take that signal and decode it to DPLx(II) right?

As i understand it... isnt' DPLx suppose to have L,C,R and the phantom surrounds?

I'm only getting center and surrounds.. no fronts when i use DPLX music or DPLx movie.. is that off or what?

I'm not getting any sound from my fronts.. i found out today. but when the material changes to stereo or DD or DTS.. the fronts work just fine like they should.

IS there some setting i have wrong for DPLx? since i'm not hearing any left and right fronts?

thanks

A couple thoughts... First, for the way Pro Logic II and IIx are behaving, you'll probably want to check the "Center Width" setting in the "Surround Config" menu - if you are currently set at or near 0, the processor will pull almost all of the front soundstage to the center channel (leaving little or nothing for the left and right speakers), while if you set it up around 7 (the maximum setting) it will push almost everything in the front soundstage out to the left and right channels (leaving little or nothing in the center channel). Stereo would of course send everything to the fronts only, while DD will just do the Dolby Digital decoding (which for DD 2.0 tracks will give you the same result as stereo). The DTS button will only work at all when you have either a DTS source (allowing you to toggle between DTS and DTS NEO:6) or a PCM source (allowing you to engage DTS NEO:6) - it won't do anything for a Dolby Digital source, and NEO:6 lacks a "center width" adjustment so it always tries to use a "standard" width.

While we're talking about cable and audio formats, here's a handy trick to tell whether you are getting PCM stereo, Dolby Digital 2.0, or Dolby 5.1 (the three audio formats that I've seen from Time Warner): the "PCM" indicator (located next "Pro Logic II" on the front panel) will tell you if you're just getting PCM stereo, while if PCM isn't on you can look to see if the "LFE" indicator is on (bottom of the speaker indicators, just above the surround back indicator) to see if it's DD 5.1 or DD 2.0. Whether PCM is on or not and whether LFE is on or not can tell me what the audio source is for a cable program even from a distance.

thanks gonk, you got that right.. when i reset the 990 last week... i forgot to change the width from 0 to about 4 where I usually have it.

thanks

Now what does panarama do then?

If panorama is "ON" the 990 will steer more data into the surrounds than it would otherwise do.

That shouldn't be happening, unless you're listening to a mono source. The Centre Width parameter only affects correlated (in-phase) mono sounds, which would have phantom imaged in the centre of the front soundstage anyway. Stereo sounds should remain firmly in the front L/R speakers no matter where the Centre Width parameter is set. Or at least that's how PLII/PLIIx works for me.

i thought PLII was front left, center, right and phantom surrounds... or was i wrong? and if you use the width setting.. you are pulling center channel sound out to your right and left fronts.

For anyone who is interested in what is happening technically, I'll elaborate a bit on Gonk's reply.

When surround processing extracts a centre channel, it also inverts the phase of that signal and sends it back to the front L/R channels. What this does is cancel only the centre channel information from the L/R speakers, leaving all other sounds intact. You want to hear dialogue from the centre speaker, not all three front speakers. That would sound bad.

Similarly, when surround information is extracted, information from the front L/R channels is phase-inverted and sent as a cancellation signal to the surround channels. If the processing didn't do this, sounds from the front L/R channel would leak into the surrounds, cause the front soundstage stretch really wide and wrap around the front of the room. And that sound bad.

Or would it?

Turns out on some music material, a huge and lush front soundstage sounds absolutely spectacular. So Dolby gave listeners the option to turn the cancelation signal On or Off. Set the Panorama parameter to On, and your front soundstage becomes more panoramic because the cancelation signal isn't sent to the surrounds. Turn Panorama Off, and the front soundstage shrinks to become more realistic because front sounds are being cancelled from the surrounds.

If you plan on listening to 2-channel music in surround, I would take just a few seconds to see if the Panorama setting sounds best On or Off. Like I said, it's source dependent. And probably not something you want to use with 2-channel movie/TV sources, where front soundtage articulation is more important wrap-around envelopment.

"Phantom" is the term used to describe sound coming from a location where there is no speaker. For example, when listening with 2 speakers, you hear a phantom centre. No speaker there, but sound still images in the centre of the front soundstage. It's a phantom image.

PLII doesn't generate phantom surrounds. It extracts ambient information from 2-channel sources and sends that information to actual surround speakers.

By contrast, the Dolby Virtual Surround mode does generate phantom surrounds. By using only two front speakers, it creates the impression of surround information being around you, even when there are no surround speakers. Correct. Every recording has sounds that image in the centre of the front soundstage. But in order to hear these at the correct location, you need to be sitting in the sweet spot exactly between your L/R front speakers. Since phantom images don't exist (they're created in the brain), when you move off-axis, the phantom centre image moves with you.

PLII extracts those sounds and sends them to the centre speaker, cancelling them from the L/R speakers. Now you can be sitting anywhere in the room and sounds intended for the centre of the soundstage will always image in the centre of the soundstage.

The Centre Width parameter lets you control the surround processing. You get to choose exactly how much centre content is extracted and how much is left in the L/R speakers. Personally, I set it close to minimum width. If something was supposed to image dead centre of the front soundstage, I don't want it blurred between all three front speakers.

But that's me. You should experiment with the Centre Width parameter and find which setting works best for you. It may even change, depending on source.

Excellent explanations, Sanjay. The only thing I can think to add is a detail about how Pro Logic II/IIx differs from Pro Logic. The original Pro Logic produced a center channel and a mono surround channel in addition to the left and right channels. Pro Logic II went a step further by (among many other things) producing five separate signals: left, right, center, left surround, and right surround. Additionally, Pro Logic IIx also produces separate left surround back and right surround back signals.

sorry if i keep beating a dead horse here guys.. but if i understand this...

if i am listening to something in PLII i should have 5 channels of audio correct? LCR and surround left and right?

If this is correct... then i'm not getting front left and right for some reason. Unless i apply the center width. with extends a signal to the left and right fronts.

Yes, Pro Logic II will produce five channels of audio. However, as Sanjay points out, that is going to be dependent on the source material and influenced by the Center Width setting. A mono source (even if carried equally by both left and right channels) would tend to be reproduced solely in the center. Similarly, I'd expect programs that are nothing but dialog to tend to do the same thing (since the dialog is going to want to be anchored to the screen and therefore should be steered to the center).

Here's something that might be useful to our discussion. The quote below was taken from page 31 of the 990's manual.
Based on that, STEP 0 on the 990 should yield no data in the left and right channels.

Are you sure you're listening to a stereo signal? What you're describing has never happended to me when using PLIIx, unless the source signal is mono. The processing circuit can only steer mono content to the centre speaker, so stereo information should remain fixed in the L/R speakers even when the Centre Width parameter is set to 0 (minimum). Trying playing a CD that you know has a wide front soundstage and various Centre Width settings. Irrespective of those settings, the soundstage shouldn't shrink.

I've got a question for you, Sanjay. Could it be that a center width of 0 actually allows the audio to steer entirely to the center? I noticed that the MC-12 manual lists its available adjustments for center width as 1 to 6 rather than the 990's range of 0 to 7, which is what gave me that idea.

No. At least never in my experience. Do you have any stereo sources with strong left-vs-right content that you could test it on? For example: if you have a test CD that has an isolated left channel signal, see if you can get it to collapse to the middle using the Centre Width control. Steps 0 and 7 have been re-labeled Min and Max, respectively, to make it easier to remember which end of the range does what.

BTW, I don't know if you're aware but the PLII Movie mode is the equivalent of setting the Centre Width to 0 in the Music mode. If you're not experiencing collapse when using PLII Movie, then you shouldn't with PLII Music.

I've actually not tried this myself and haven't noticed the sort of complete collapse that Skyblazer's found, but my Devious Tiny Disc has tracks with dedicated left-only and right-only audio on them. If I get a chance, I'll see what I can come up with.

yes, maybe my source from the cable tv was mono.

when i use a known stereo signal i get all three front channels working..

PLII movie has a narrow/center weighted field

PLII music is a wider sound field.

ok. it does make sense to me know.

thanks