HDTV 5.1 surround sound problems? (1 Viewer)

[systemlord]

I have Cox HDTV/DVR service and I have noticed that both my surround speakers LS&RS seem def unless I crank up the fader to the max 12db's. When I pop in a DVD the RS&LS are so loud that I have to turn them way down to 3&4 db's, my fronts are @ 0db's. I have a Denon AVR 5700 140watts X5, with my front speakers @ 4ohms and rear's @ 8ohms and am using fiber for sound, have tried coax no change. I give a huge breathing room for my Denon as the temp. sessitive fan only turns on when I really crank it up but I don't do that very often. My signals are perfect as my internet speeds are 12-16 megs, signals are: Ds SNR32.9, RX 1.9, TX 42.1. SO WHATS UP???

 

[Dick Knisely]

By your description everything is working properly in the sound system.

Is this right:
-- With a DVD you're getting output to the surrounds.
-- With the cable box you're not getting much if anything to the surrounds.

If so, then there are a couple possibilities. First, how is the sound routed from the cable box to the AVR? Sure that cable is okay? Have you tried switching the receiver modes--i.e., try 2 channel stereo, the 5-channel "stereo" mode and any DSP surround modes. If those put sound in the surrounds then either the cable box is faulty or there's simply no surround info in the signal.

 

[LanceJ]

Based on reading these boards, I'm getting the sneaking suspicion that many times when a broadcaster is sending a 5.1 Dolby signal, either of two things is occuring:

* except for the front left/rights, there is nothing actually in the other channels

* just like so many concert dvds & DualDiscs use, the broadcaster is getting cheap and using a DSP box to generate a fake 5.1 signal, where all you get in back is some blurry reverb or the occasional out-of-place sound randomly popping up.

Either way, IMO the main reason for this is so that the customer's L, C, R, RS and LS indicators light up on their receiver........because the brochure talked about the "stunning" surround sound HDTV can provide. :rolleyes

I don't know why more companies at least just use the Dolby Surround system, since SO many movies beginning in 1977 use that format. This can provide a pretty decent sense of space and clearly audible directional effects. Back in the day, at work we used The Abyss and Terminator 2 - on VHS Hi-Fi tape - all the time to show customers what an HT system was capable of. FYI: this used to be the case for many movies and TV series on the Sci-Fi Channel, until Time-Warner or whoever decided to stop transmitting in stereo a few months ago (Dolby Surround requires a left + right signal to carry the matrixed rear and center channels).

BTW: for people with dvd players connected to a Dolby Surround or Dolby Pro-Logic system via the left/right analog outputs, you may or may not hear surround effects when a dvd with a 5.1 soundtrack is being played. That's because the player is downmixing the 5.1 channels into a 2.0 signal (and tossing the .1 i.e. the LFE channel in the process): this mashed up signal usually just "confuses" the surround decoder chip. So if its available, use the dvd's Dolby Surround track which is actually a stereo track. And sometimes, even a non Dolby 2.0 track contains some natural surround info the decoder can use (same with lots of music CDs).

 

[systemlord]

O my god, everything you have said makes so much sense! Dolby Digital on most stations sounds like reverb in the rear speakers! The only channels that get real 5.1 are HBOHD and most movie channels. There's no positional FX's in the LS&RS, they both fire the same thing = reverb. As far as stereo broadcasting it is not in stereo anymore because when I switch to stereo my Denon still show the channel indicator as 5.1 all channels lit. I can't get Prologic anymore because without stereo you can't get Prologic. So you know what I did, I disconnected that cable from my HDBOX and plugged it in directly in to my TV and guess what? I got on my channel indicator FR, FL, LFE, S lite up meaning that I had both surrounds working in Prologic mode. But when I plugged the cable back in the HDbox I lost Prologic mode, that pisses me off, as I have to choose from 5.1 with reverb if you want to call it that or no HD and Prologic! thats not much of a choice!! As for 5 channel stereo it still sound mute, but with DVD's its a whole nother story! DAM IT!!

 

[systemlord]

O my god, everything you have said makes so much sense! Dolby Digital on most stations sounds like reverb in the rear speakers! The only channels that get real 5.1 are HBOHD and most movie channels. There's no positional FX's in the LS&RS, they both fire the same thing = reverb. As far as stereo broadcasting it is not in stereo anymore because when I switch to stereo my Denon still show the channel indicator as 5.1 all channels lit. I can't get Prologic anymore because without stereo you can't get Prologic. So you know what I did, I disconnected that cable from my HDBOX and plugged it in directly in to my TV and guess what? I got on my channel indicator FR, FL, LFE, S lite up meaning that I had both surrounds working in Prologic mode. But when I plugged the cable back in the HDbox I lost Prologic mode, that pisses me off, as I have to choose from 5.1 with reverb if you want to call it that or no HD and Prologic! thats not much of a choice!! As for 5 channel stereo it still sound mute, but with DVD's its a whole nother story! DAM IT!!

 

[LanceJ]

Systemlord: does your cable box have left/right analog RCA jacks? If so, maybe those could be used via an unused analog input on your receiver so you could activate DPLII, DTS:Neo, etc. Becuase contrary to what urban myth says, analog connections are not *always* the sonic horror some people make them out to be.

 

[systemlord]

Yes it does have two channel stereo, but it sounds like hell! I'm not to imprest with HDTV 5.1 sound. Its clean sounding but it sounds like the Dolby Digital is being down sampled to 3.1 Dolby Prologic. The broadcasters just don't care about the future of HD & HD sound as it costs lot of $$ to convert to true HDTV, there are sets out there that are capable of 1080P. but thats a few years down the road, but Blue ray should be able to do 1080P. Channel 7 ABC is now HD full time now.