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NBC: no dolby 5.1?

post #1 of 18
Thread Starter 
I just got my home theater set up, have panny plasma with tuner built-in, outputting digital optical to my audio system. ABC sounded great last night, but watching Conan on NBC i realized i couldn't hear the bass guitar at all... the subwoofer channel was dead. Audio system said channel was dolby digital 3/2. Flip to ABC and it's fine... Why does NBC appear to not be sending a ".1" signal for the sub?
post #2 of 18
Quote:
Originally Posted by kontrabass View Post

I just got my home theater set up, have panny plasma with tuner built-in, outputting digital optical to my audio system. ABC sounded great last night, but watching Conan on NBC i realized i couldn't hear the bass guitar at all... the subwoofer channel was dead. Audio system said channel was dolby digital 3/2. Flip to ABC and it's fine... Why does NBC appear to not be sending a ".1" signal for the sub?

In Detroit at least, I know for a fact that Leno and Conan are flagged and show up as 5.1 but are infact only 2.0
post #3 of 18
As has been discussed ad naseum in multiple threads, NBC and FOX leave the 5.1 light on even when no one is home.
post #4 of 18
Heck, in some areas (like Baltimore with WBAL) there's never any Dolby Digital passed even for shows that technically do support it.
post #5 of 18
Thread Starter 
Thanks for the replies. I guess now I just need to figure out how to downgrade the audio or something... My front speakers are so dinky I get no bass at all without the sub. My receiver says there's an LFE signal and so it doesn't do anything with the sub I guess.

Anyway I guess this is between me and my Sony receiver now
post #6 of 18
The networks decide if shows will be provided to locals in HD and with DD 5.1. However, implementation is not consistent across local stations.

In the Cleveland market, local stations support DD 5.1 on NBC and Fox. ABC is in the process of getting DD 5.1. The local CBS station seems to believe that implementation of DD 5.1 isn't worth the money.
post #7 of 18
Quote:
Originally Posted by rlb View Post

The networks decide if shows will be provided to locals in HD and with DD 5.1. However, implementation is not consistent across local stations.

In the Cleveland market, local stations support DD 5.1 on NBC and Fox. ABC is in the process of getting DD 5.1. The local CBS station seems to believe that implementation of DD 5.1 isn't worth the money.


But Fox was able to do it cheaply based on the way their network is set up.

CBS gave you local News in HD.

As this is the HD forum, not the 5.1 forum, most HD people would consider that a great trade off - as that is an expenditure in excess of $3 Million.
post #8 of 18
SOmewhere, in the setup menu of your DD (audio) Receiver, there should be a setting that specifies whether your speakers are "large" or "small". When set to "small", the receiver should funnel some bass to your subwoofer, rather than to the "small" main speakers.

The "x.1" channel usually just carries additional bass information, and is technically the LFE or "Low Frequency Extension" channel, sometimes referred to as "Low Frequency Effects".

Due to some problems with the current satellite distribution of NBC-HD, many affiliates just leave the "5.1" indicators turned on all the time they are on NBC's HD programming.
post #9 of 18
As this is the HD forum, not the 5.1 forum, most HD people would consider that a great trade off - as that is an expenditure in excess of $3 Million.[/quote]

Really now, I don't think there should be any trade offs. A Local station that is a major network affilate should be cancelled by the network for cutting corners on their own. This particular station can't even broadcast a viewable HD signal 50% of the time let alone with DD 5.1. DD 5.1 is part of HD. No trade offs.
post #10 of 18
Networks don't always care about the station's ability to pass HD or 5.1. In smaller markets, it's the station's ability to buy the network programming and not have the check bounce that really matters.

Any viewer is welcome to come up with the funds to build a station and outbid the current affiliate for the rights to purchase and rebroadcast network programming.
post #11 of 18
Well they should care. If I get a crappy feed from a local network I turn the station. Less viewers less advertising dollars.
post #12 of 18
As more local stations buy audio switching boxes such as Optimax and Neural encoders, the 5.1 signals we see on our home receivers don't mean the channels are actually being used. Stations have problems switching between genuine 5.1 sources (such as HD network shows) and all the other content that originates in stereo. Octimax and others send out everything as 5.1, eliminating the jarring audio switches between sources. These boxes pass through real DD 5.1 tracks and they re-encode stereo sources as synthesized 5.1. The net effect is that stereo material often ends up almost completely in the center with only music in the other channels. Some well mixed stereo material will sound pretty good - this year's Rose Bowl, for example. Other material often ends up sounding mono. But, at least the voices are in the center channel, which is probably better than stereo for talking heads.

Local station issues aside, there are also huge variations in the quality of the 5.1 mixes. Some shows and sports production crews care about the 5.1 mix. Many others don't. They're happy if it sounds good in stereo, which is all the vast majority of people hear, even many of those with HD sets. Kind of sad.
post #13 of 18
NBC's metadata 2.0/5.1 switching hasn't worked since the Olympics. It stays in 5.1 even on 2.0 material.

CBS/CW's works most of the time, but depends on the local station being setup correctly. If there is a problem with the metadata, the system is supposed to default to 5.1 to ensure dialog is not lost on 5.1 shows.

ABC does not have metadata switching. It appears that the stations do the 2.0 and 5.1 switching on a per program basis, so 2.0 commercials during a 5.1 show will still be indicated as 5.1.

Fox's splicer system does not require metadata switching, assuming the station airs the Fox network stream directly without re-encoding. 2.0 material is converted to 5.1 at the network.

NBC and CBS (probably ABC too) send a secondary 2.0 stream for stations not in 5.1. CW may be the most complex with four audio streams - Dolby E, AC3 2/0 (2.0), AC3 3/2L (5.1) and MPEG 2.0 - plus the CBS style VANC metadata.
post #14 of 18
ABC always sends a 5.1 signal to affiliates, but if a show is produced in 2.0, two of the channels will have audio; the rest will have silence.
post #15 of 18
Quote:
Originally Posted by TVOD View Post

CBS/CW's works most of the time, but depends on the local station being setup correctly. If there is a problem with the metadata, the system is supposed to default to 5.1 to ensure dialog is not lost on 5.1 shows.

Is the CW sending 5.1 or has my affiliate just given up on it? We were getting 5.1 for shows like Veronica Mars and Everybody Hates Chris at the beginning of the season but we were also having a problem where it would switch between 5.1 and 2.0 every few seconds for several minutes. Now everything is 2.0.
post #16 of 18
I have noticed that here in KC, NBC has been DD 2.0 since the beginning of the year. Is this NBC national or my local affiliate?
post #17 of 18
Quote:
Originally Posted by scowl View Post

Is the CW sending 5.1 or has my affiliate just given up on it? We were getting 5.1 for shows like Veronica Mars and Everybody Hates Chris at the beginning of the season but we were also having a problem where it would switch between 5.1 and 2.0 every few seconds for several minutes. Now everything is 2.0.

Last I checked was also at the beginning of the season. No chance tonight on WWE. From what I remember, WB HD had Dolby E, AC3 5.1 and MPEG 2.0. CBS added the AC3 2.0 because they use it for the CBS HD net feeds.
post #18 of 18
NBC-HD uses satellite receivers with 8 channels of audio (4x AES pairs): L/R Front, C/LFE, Ls/Rs, and L/R Stereo mix.

Some stations may be using the stereo mix, to work around some problem. If using the 5.1, they need to create a metadata stream that matches the one provided by NBC-HD, or take the one NBC sends out. They can use the NBC metadata to switch with, or do their own switch...manually, or via automation control.
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