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Topic: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent? (Read 1014 times) previous topic - next topic
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Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Shockingly hard to find a decisive answer on this. Just about every Blu-Ray in the last decade comes with Dolby Digital Plus (DD+) or DTS-HD MA (Digital Theater Systems High Definition Master Audio). You would think these usually-lossless formats would ace their older versions (DD and DTS) in a blind listening test if they went through all the trouble of a new format and new receivers.

So where are those tests? No smoking gun on Google Scholar. With 480p -> 1080p video the difference was obvious. If there was a difference from lossy to lossless here you'd think they would market based on that. I didn't do a blind test but DD sounds fine on my system. I doubt I could pass an ABX. There was no part of the audio that felt distorted or wrong. Nothing on the HA wiki either which surprised me.

Note p22 here. https://tech.ebu.ch/docs/tech/tech3324.pdf

EBU – TECH 3324
EBU Evaluations
of
Multichannel Audio Codecs
Status: Report
Source: D/MAE
Geneva
September 2007

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #1
DD Plus supports more channels, higher bitrates to support them, and allowed for Dolby to continue to receive patent license money. DD+ is also lossy. TrueHD is lossless. At 640 kbit/s and 5.1 ch Dolby sounds great and is compatible with old equipment.

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #2
Some number of years ago, I read an article from some HiFi magazine or something like that. The authors were invited to Dolby Labs. At Dolby, they went into a room that was decked with some really nice equipment. Interesting thing was, Dolby had setup a system to do blind testing. The result was, regular old Dolby Digital at 640 Kbps was indistinguishable from higher bitrate material. I've searched for that article and I can't find it.

I like the releases of lossless material, if only because I can compress a movie and shrink the audio without losing quality. I'll lose Atmos, but then I'm only doing 5.1 and no Atmos capable equipment.

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #3
If there was a difference from lossy to lossless here you'd think they would market based on that.
The lossless part of TrueHD and Master Audio was made quite clear to me. I think they did market on the lossless part. Perhaps they just didn't market it as such to you?

Quote
Note p22 here. https://tech.ebu.ch/docs/tech/tech3324.pdf
Why do you feel that isn't enough proof that these codecs aren't transparent to everyone at these bitrates? To me it seems quite clear?

Obviously, only you yourself can assess whether a codec at a certain bitrate is transparent for your ears, mind and installation. But the EBU paper makes it clear that (trained) ears can hear the difference.
Music: sounds arranged such that they construct feelings.

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #4
I've got a shelf-full of concert DVDs, but I think only one concert Blu-Ray, and I'm not sure what formats or on it so I'm not sure if I could set-up a valid A/B or ABX test, and it would only be one disc...

But...   Some of the best-sounding and most-enjoyable music I have are concert DVDs with 5.1 Dolby AC3 or DTS.   When there is a stereo LPCM track, I'll choose the lossy surround.

...When I first got a DVD player and set-up the surround sound I may not have been aware that it was lossy.    

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #5
If there was a difference from lossy to lossless here you'd think they would market based on that.
The lossless part of TrueHD and Master Audio was made quite clear to me. I think they did market on the lossless part. Perhaps they just didn't market it as such to you?
Lossless is a technical detail. If you could hear a difference, I would expect marketing based on outcome. 1080p is a bullet point, "clearer picture" is a selling point.

Quote
Quote
Note p22 here. https://tech.ebu.ch/docs/tech/tech3324.pdf
Why do you feel that isn't enough proof that these codecs aren't transparent to everyone at these bitrates? To me it seems quite clear?
I know nothing of this paper's rigor. It's very technical and the results I'm looking for don't seem to be a focus. There's clearly a difference in codecs but I can't even tell if ANC_Original is the raw lossless audio. It looks like DD+ is rated worse as DD, which is unexpected and warrants follow up experiments.

It's weird to me that this "proven" fact has been experimented one single time in one obscure paper. It should be an easy thing to test in an audiophile or home theater site.

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #6
If there was a difference from lossy to lossless here you'd think they would market based on that

You already gave yourself an answer.

1. Most people will spend more money on TV (video) than audio.
2. Most TVs have terrible audio compared to dedicated receiver/amplifier/speakers. (which most people are not going to buy)
There are not going to be audible differences. Why promote something that most people cannot tell the difference?
3. Jump from VHS -> DVD -> BR was massive. Everybody can see the obvious difference.
4. DD and DTS are only used for movies. You are WATCHING movies. Your eyes are focused, not ears.

It makes perfect sense to push video marketing instead of audio marketing.

Edit:

I think their marketing was perfect.
Take a look at MQA for example. It was marketed as the audio evolution. The greatest thing ever. Well, turns out MQA is shit. Now everybody is avoiding it.
Now imagine if salesman put up an ABX test between cheaper lossy and expensive lossless device.
You are obviously not going to hear the difference. (unless test was rigged)
Your reaction will be "this idiot (salesman) is trying to sell me more expensive equipment that makes no difference, he is trying to scam me"
and he will lose the customer.
gold plated toslink fan

Re: Dolby Digital (DD) and Digital Theater Systems (DTS) - Transparent?

Reply #7
Shockingly hard to find a decisive answer on this.

Yes, this somewhat astonishes me as well.

You would think these usually-lossless formats would ace their older versions (DD and DTS) in a blind listening test if they went through all the trouble of a new format and new receivers.

Imagine that digital audio in general has long surpassed any human being's hearing capabilities and even many lossy codecs such as AC3 or DTS offer dynamic ranges and frequency responses which most consumers aren't even close to utilize at home in already quite decent 5.1, not counting any matrixed additions, what shall one come up next? There is hardly and room for improvements (the real headroom for them being mostly uncomfortable such as better speakers and especially room acoustics) so what shall they come up with next? It is only too tempting to introduce solutions looking for a problem as nowadays it is easily doable and one can sell new AVRs, etc.


So where are those tests?

Probably for popularity and thus attention reasons, mostly MP3 underwent decent listening sessions where many participants scored way worse than they thought even with CBR modes or other suboptimal conditions. Since apparently neither they got crazy for too many AAC multichannel analysis, I guess there is hardly any interest, given the lack of AVR support (at least via S/PDIF or HDMI), lossless capabilities of physical media and well-established (E-)AC3 usage otherwise.

I doubt I could pass an ABX.

Same here. At least with the cores or supplemental streams of 640 kbps for AC3 or ~1.5 Mbps for DTS, it is also quite unlikely to run into artifacts as this discussion (in German though) also showed when they eventually subtracted the lossy decode's result from the original and check for what was left (almost nothing).

1. Most people will spend more money on TV (video) than audio.
2. Most TVs have terrible audio compared to dedicated receiver/amplifier/speakers. (which most people are not going to buy)
There are not going to be audible differences. Why promote something that most people cannot tell the difference

Just as an addition as these points might be misleading to some:

It is not that great audio equipment would easily reveal lossy formats as such, in opposite, especially they can sound fantastic and still be transparent compared to their lossless counterparts.