5.1 PCM vs. Dolby digital 5.1?

[rarredoa]

This is gonna sound like a crazy question to all you technophiles
but why don't I notice a difference between the Dolby Digital and 5.1 PCM sountracks on my movies, such as Pirates-deadman's chest and apocalypto. I am using my PS3's HDMI output set to PCM and going to my Onkyo 1.3 HDMI receiver, the 605 model. Any settings on the receiver that i should be aware of? the listening modes give me options of either "direct" or "multi-channel" for the input options on the receiver's setup menu. When I switch between listening modes on my PC (X-fi soundcard outputing analog to receiver, Cyberlink PowerDVD blu-ray edition and sony BWU-100A) I notice a night-and-day difference between those two sound modes! Any tips?

Thanks

[mgarceau]

well i have the onkyo 604 and the ps3 connected via hdmi, and i for sure notice a difference in dolby digital and pcm. i know my receiver says multichannel on the display when playing movies.

[desmond]

Uncompressed TrueHD is bit equivalent of PCM (identical). Your receiver does not know what track is being used and will always say multichannel pcm. Unless there is some major bug in your reciever's DAC's they should sound the same.

[blueyeboy]

I just picked up a Panasonic DMP-BD10A Blu Ray at Best Buy this weekend. Vey nice player by the way. I'm a bit confussed about all the hype on uncompressed PCM. I've tested both Dolby Digital 5.1 on POTC (640 Kbit/s) vs. the PCM track thru my analog outs. The PCM sounds a LITTLE bit better in turns of range and fidelity.

My point is after some research online, full Dolby Digital (640 Kbit/s) and (DTS 1.5 kbit's) on these Blu Ray discs should rival lossless version. I just don't think there is a night and day difference.

My speaker set up is with some nice Energy's with a top Yamaha receiver.

[ClaytonMG]

You think that full bit DTS tracks should rival uncompressed audio? I think you might be confused... a regular DTS track has a bit rate of 1.5mbps, a lot of PCM tracks are at like what? 6.9mbps? If you can't tell the difference, and these are not insults but actual characteristics of average listeners, it's possible the speakers aren't very good, the reciever might not be the best one, or it's also possible that your ear isn't as finely tuned as other people's. I know I hear a lot more frequencies that most people, which bothers the crap out of me. Nothin worse than waiting for someone to take a picture with the flash on... The continuous high pitched noise is just terrible...

[blueyeboy]

This is taken from the Hi Def Digest review of Blu Ray Happy feet which got passed over from Warner getting a Dolby True HD track. Insteed it received a DD 640 kbps track.....

It seems like from the review the average listener would not be able to tell the difference.



The Audio: Rating the Sound


Alas, Warner continues to give Blu-ray short thrift when it comes to audio. It's been a sorry trend, with the studio failing to offer Dolby TrueHD tracks and/or comparable DTS-HD or uncompressed PCM mixes on their A-list Blu-ray titles, while their HD DVD counterparts boast high-resolution audio. (The PCM track that Warner included on the Blu-ray edition of 'The Departed' last month appears to have been an anomaly.) As such, all that the Blu-ray of 'Happy Feet' gets is a Dolby Digital 5.1 Surround EX track in English, French and Spanish. Unfortunately for audiophiles, this just can't compare to the full-blown Dolby TrueHD mix on the HD DVD.

On the bright side, 'Happy Feet' boasts excellent sound design, and without the TrueHD track to compare it to, this track sounds perfectly good. From the opening sequence, which uses Prince's classic 'Kiss' to hilarious effect, the dynamic nature of the soundtrack is obvious. Frequency response is very good on the EX mix, from the drum-tight low bass to wide mid-range. All the voices sound quite good, with a smooth clarity to the highs. Surrounds are also aggressive, from all manner of discrete effects (the sea lion and whale attack sequences are particular standouts) to excellent integration of the score and songs. Movement is often directed all around the soundfield with pinpoint accuracy, and imaging is near-seamless. I also have no complaints regarding the ambiance, with even milder scenes usually having something going on in the rears, which keeps the soundtrack alive and immersive.

Unfortunately, where this EX mix falters next to TrueHD is in the lowest bass, which never quite packs the same heft. The depth of the soundfield is also flatter on the EX, a drawback that is not immediately noticeable to the ears, but becomes quite clear after a few direct comparisons. To be clear, the average listener likely won't recognize what they're missing, but when it comes to delivering the best audio high-definition can offer, Warner continues to sell Blu-ray short.

[NutsAboutPS3]

Originally Posted by ClaytonMG

You think that full bit DTS tracks should rival uncompressed audio? I think you might be confused... a regular DTS track has a bit rate of 1.5mbps, a lot of PCM tracks are at like what? 6.9mbps?

The bitrate comparisons are meaningless - one is compressed and the other isn't. Do you look at zip files and say that they can't possibly contain the original information because they're so much smaller?

http://www.answers.com/topic/digital-theater-system
"In the consumer (home theater) market, AC-3 and DTS are closer in terms of audio performance. When the DTS audiotrack is encoded at its highest legal bitrate (1.5 MBps), most technical experts regard DTS as achieving perceptual transparency (i.e. indistinguishable to the uncoded source in a double blind test.) At AC-3's maximum bitrate of 640 Kbps, Dolby claims similar transparency."

[Dawid]

Hi.just joined your forum. I have a sony bluray player connected to lg 5.2 surround soud via hdmi. The surround sound supposedly detects the sound. If i play normal dvd it changes to 5.2 dolby digital. If i play bluray it changes to stereo pcm. Why doesnt it want to play surround sound in pcm format from bluray? The bluray player is set on 5.1. I tried 3 different disks. Im fairly new to digital sound and HD

[htgeek]

The differences are very slight, watch the first scene of The dark knight where the criminals go across the zip line. First in lossless and you'll hear them all the way across to the other side where in a normal DD5.1 you loose that. Or coffee cups clinking when the kamikaze's fly over head in Pearl Harbor. That's where the rubber meets the road. Not only if the information is there but can your room and system show those little details that are there. That's the difference.

[Tech-UK]

Originally Posted by Dawid

Hi.just joined your forum. I have a sony bluray player connected to lg 5.2 surround soud via hdmi. The surround sound supposedly detects the sound. If i play normal dvd it changes to 5.2 dolby digital. If i play bluray it changes to stereo pcm. Why doesnt it want to play surround sound in pcm format from bluray? The bluray player is set on 5.1. I tried 3 different disks. Im fairly new to digital sound and HD

Could you tell us the exact model numbers of both the player and sound system please.

[schan1269]

Originally Posted by Tech-UK

Could you tell us the exact model numbers of both the player and sound system please.

It is probably the ARX80/8500.

Probably doesn't decode lossless audio. I'm not littering my hard drive with the manual.

[Dawid]

Yes its the arx 8500 surround 5.2

[schan1269]

Originally Posted by Dawid

Yes its the arx 8500 surround 5.2

What does the owners manual say it decodes?

If it (likely) does not decode lossless audio, then your BD player needs to decode lossless to something other than 2.0 PCM.

[Tech-UK]

Seems that it just decodes DD.

I would set the Blu-ray player to output PCM.

[Dawid]

The bd player has only 2 settings on the output audio pcm or auto. If its on pcm the all tge movies is pcm 2 channel. If its on auto then normal dvd plays on dolby digital 5.1 and bluray on pcm 2 channel. What do you guys suggest i do? Buy a bd player that decodes lossless or can it be my hdmi cable?

[Tech-UK]

Originally Posted by Dawid

The bd player has only 2 settings on the output audio pcm or auto. If its on pcm the all tge movies is pcm 2 channel. If its on auto then normal dvd plays on dolby digital 5.1 and bluray on pcm 2 channel. What do you guys suggest i do? Buy a bd player that decodes lossless or can it be my hdmi cable?

What model is your Blu-ray player?

[Dawid]

http://m.lg.com/za/support-product/lg-ARX8500

This is the lg surround sound

[Dawid]

http://www.sony.co.in/product/bdp-s1100

The bd player

[schan1269]

Originally Posted by Dawid

What do you guys suggest i do?
1. Return it and buy a real audio system.
2. Short of that, buy a BD player that can decode lossless in 5.1. Which obviously your player does not do. Lots of bargain end BD players no longer decode to 5.1/7.1. It is "why bother putting that in there when 99% of people connect it to a TV or an AVR for decoding". Cause only 1% buys audio equipment that can't decode.

Buy a bd player that decodes lossless or can it be my hdmi cable?
Your BD player is decoding to 2.0 PCM, like all bargain BD players lately. No...it is not the HDMI cable.

This is why nobody likes HTiB. Limited connections and capabilities. I'm glad LG doesn't sell that in the US.

[Tech-UK]

Originally Posted by Dawid

http://www.sony.co.in/product/bdp-s1100

The bd player

Under 'Audio Settings' then 'Downmix' make sure that 'Surround' is selected, and then under 'DTS Neo:6' make sure that 'Off' is selected.

Also make sure that under 'Digital Audio Output' that 'PCM' is selected.

Now if the Blu-ray has a Dolby TrueHD 5.1 or 7.1 track, this will get decoded to PCM 2.0, this is a limitation of the Blu-ray player.

If the audio track on the Blu-ray is DTS-HD Master Audio, this will be decoded to PCM with full channels (that's if the track is 5.1 or 7.1, 2.0 tracks will obviously still be only 2.0) and that should then be output to your sound system.

You are still getting HD audio, its just that your Blu-ray player is decoding the audio track rather than your sound system.

Try the above and see what happens.