LFE track in ProLogic?

scottvamp

Get over myself - what are you talking about!!!!!!!!!
I was agreeing with you the entire tread.

Dr. Spec

Russ' link was interesting, but it still doesn't explain why I don't get the bass hits in those specific scenes. They are totally missing. It simply can't be downmixing everything.

Maybe it's my POS upstairs DVD player?

Can anyone else try those scenes in 2 channel if they have a spare rig?

scottvamp

Originally posted by RuSsMaN
End of **** discussion. You have the DD 5.1 info downmixed into a 2ch Dolby Surround encoded stereo signal, which is passed to the Prologic decoder in the receiver.

Jesus H Christ.

Cheers,
Russ

No speakie Doc!!!!!!!!!!!!!!

RuSsMaN

Doc, I hate to state the obvious, but is your 'dsp' on said input set to prologic? I've seen some rec's that do it automatically, but most require you to change the setting manually.

Another thought I just had that might throw a wrench into the equation, does you player have 5.1 preouts, and you are only using the 2 main (l/r)?

Cheers,
Russ

Dr. Spec

It's just a 2 channel stereo receiver, and the DVD player only has a digital coax output, and L/R analog outputs.

Since the stereo receiver isn't DD/DTS, I can't connect a digi coax to it. So I just connected the L/R analog outputs to it from the DVD player.

It's mostly for the kids to watch Disney stuff or w/e, and I just noticed a complete lack of bass hits on certain scenes where I knew from experience that the bass was very strong. So I assumed I was losing the LFE channel.

Vocals come through OK, though.

RuSsMaN

Doc, I've got a piece of gear I want to send you, just for grins.

Email or pm me your addy.

Cheers,
Russ

scottvamp

I want a piece of gear for grins.:p
scott aka:the guy being ignored

walk

Ok here's what I did.

Unplugged the digital connection from my DVD player.

Plugged in the analog 2-ch "stereo" left/right cables to my AVR, Onkyo 700.

Popped in some disc, Toy Story I think, with "THX Optimode".

I don't have an Avia disc handy...

In the THX section there is a speaker test. It's encoded in Dolby Digital 5.1 (EX, or 6.1 actually). It sends a test tone (pink noise) to each discrete channel, seperately, including the "subwoofer" channel (LFE?).

I set the receiver to "stereo" mode - left and right output only.

The results:

Left channel - plays in the left speaker.
Center channel - plays in both left and right and sounds more or less "centered" between them, as you'd expect.
Right chanel - plays in the right speaker.
Right surround - plays sort of "out of phase" and indistict sounding, sounds *almost* like it's coming from behind you.
Back surround - "
Left surround - "
Subwoofer - SILENCE! No sound is heard from any channel.

What can I conclude from this? All main/surround channels are downmixed by my DVD player into the 2-ch. analog outputs, but NOT the LFE for some reason..

Hope that clears things up. I do know for a fact, as I orginally stated, that most/all DVD players should downmix a 5.1 mix into some form of 2-ch mix, otherwise as someone else pointed out, people with only a stereo/mono TV set would be missing the center channel and hence, 99% of the dialog in movies, rendering DVD's about useless...

RuSsMaN

That's great you went ahead and tried to test it, but it just doesn't work that way. (imo)

First, prologic doesn't know what LFE is. If you are running a subwoofer on a prologic system, you either A. Run it through the mains via a high (speaker wire) level connection, or B. Use an rca cable to connect to the 'sub out' (NOT LFE) on the receiver.

It doesn't shock me at all, that per your test method above you got nothing.

On prologic receivers, the 'sub out' is simply a single, regular pre out. Some receivers had the signal it passed choked at 120Hz, the rest passed a full range signal (to be filtered at the sub's xover).

Dolby prologic was a 4ch matrix, L C R S (left center right and surround). The low-freq info can be found on the mains, or taken advantage of through a pre-out to a powered sub as stated above, but once again NOT through an LFE jack.

The 'downmixing' of LFE is infact there, whether or not you have your system setup to make use of the information running in good ole' prologic is another issue.

I'm done with this one, I've explained it the best I know how, and posted a link direct from the horses mouth.

Love you guys.

Cheers,
Russ

gmorris

Russ,

Do you have ants in your pants? I think you do....

Dr. Spec

The issue is definitively settled on my particular DVD player. I ran Avia for all five surround channels, and the LFE channel via the L/R analog outputs.

My DVD player DOES downmix all five surround channels. It does NOT downmix the LFE channel. There is no sound present at all when I play Avia tones/tests exclusive to the LFE channel.

Two things are possible:

1) Either the Dolby website is inaccurate, and should state a DVD player using the L/R analog outputs will downmix the five surround channels but not the LFE channel.

or

2) My cheapo DVD player decoder does not meet the Dolby Labs requirement of downmixing all six channels (5.1), and instead skates by with a "5.0" downmix.

I'm not sure which is the case; all I know is what my player does with Avia.

Russ - you've got PM.

Doc

RuSsMaN

Doc, how in God's name are playing an LFE test tone, and expecting to hear it come out of what? Did you expect your 2 main speakers to rumble?

Stereo does not have an LFE channel. Prologic does not have an LFE channel. To understand, you guys need to dumb it down a little, and quit using a tone / test equipment not MEANT FOR STEREO / PROLOGIC.

Don't you guys get it?

Doc, I have a simple add-on prologic processor, with built in amps you can have for free if you want.

Ok, now I'm REALLY done with this one! Ha!

scottvamp

Exactly, first of all your cheating the theory of the original question by using a Digital Reciever. We are not talking about a DAVR here. Every DAVR may act a little different anyway depending on all the possiable settings.
Walks experiment proved to be about what me and Russ have been saying anyway.

Dr. Spec

Russ:

Here's the original question from the poster:

"My DVD player is connected to the receiver via left & right analog inputs. Am I missing the LFE track from DVD's? Or is it just summed into the analog outputs?"

It doesn't matter what kind of receiver he is connecting to because he is only using the L/R ANALOG outputs from the DVD player. It could be a stereo receiver, a DPL receiver, or a DD/DTS receiver. If you are not using any type of digital connection from the DVD player, the type of receiver is totally irrelevent to the question.

He is asking does a DD/DTS DVD player, playing a DD/DTS 5.1 DVD, downmix the LFE channel to the analog L/R outputs. The answer is no.

How in God's name are playing an LFE test tone, and expecting to hear it come out of what? Did you expect your 2 main speakers to rumble?

If the DVD player downmixed the LFE channel and included it in the L/R analog outputs, of course I would expect them to rumble.

Stereo does not have an LFE channel. Prologic does not have an LFE channel.

That is SO not the point, Russ. There is nothing special or different about the LFE channel. It is simply one of SIX digitally encoded channels on a DVD. Stereo does not have center channel, a right surround, or a left surround either. A stereo receiver has NO IDEA what the source material looks like that is being fed to the L/R analog inputs - it just plays whatever signal is present. Any signal being fed to the L/R inputs of ANY receiver is by definition NON-DIGITAL and has ALREADY been decoded.

If you are using the L/R analog outputs, the DVD PLAYER is doing the digital decoding, NOT the stereo receiver. The ONLY thing noteworthy about the LFE channel is that my DVD player will not downmix it, like it does with the OTHER FIVE non-stereo channels.

When I play Avia on my DVD player, which is connected to a STEREO receiver via the L/R ANALOG outputs, I can perfectly hear the test tones for the left front channel, the center channel, the right front channel, the left surround channel, and the right surround channel. This is clear proof the DVD player is decoding and downmixing these five digitally encoded channels to two analog outputs. It just won't downmix and include the LFE channel, that's all.

I just can't make it any clearer.

walk

Yeah I think our "cheap" (?) DVD players just cheat and don't downmix the .1 LFE channel into the 2-ch. analog outputs like they do with the other 5 channels.

Bummer, but to be honest, most people using that hookup method are probably either using TV speakers or some other setup that's entirely incapable of doing justice to the LFE anyway, and would probably just buzz and distort if they were forced to try!

warviper

I have a ps2 that was hooked to a harmon kardon avr20 that is a dolby prologic reciever not digital. Had it hooked up through the stereo rca outs and hooked it up to a klipsch rsw12 through the preouts on the avr and got some bass but know where near the bass that I get now with the optical connect and through the lfe out on my new yammy rx=v2300. Not sure if this is what you are talking about but that has been my experience.:D