AAC/AC3 vs Dolby Atmos/DTS-HDMA

[Samfandesreds]

Hello,

This may seem like a stupid question, but will I notice a difference regarding audio quality between a film with a AAC/AC3 track and the same film with a Dolby Atmos/ DTS-HDMA track, knowing that I’m not equipped with the necessary equipment ? I’m either using two standard stereo speakers or my Sennheiser HD 660s headphones, both connected to a DAC/AMP. Is lossless audio worth getting over lossy audio in this case ?

 

[kongwee]

Lossless over lossy audio. Dolby Atmos does have protocol for music. It has to be remix in Dolby Atmos format, not just dump stereo files into Dolby Atmos format.

 

[abdo123]

Atmos should be always superior, it’s the superior format of everything you mentioned.

 

[charleski]

I've compared them on a few films with multiple tracks and can't tell the difference between AC3 and Atmos/TrueHD/DTS-HDMA on my 5.1 system.
So no.

 

[JSmith]

I’m either using two standard stereo speakers or my Sennheiser HD 660s headphones

In this case all multi-channel audio is being downmixed by your source device, I assume a bluray player here. Some do a better job on this than others...

I actually prefer the sound subjectively when I use my Oppo BDP to downmix to stereo compared to the stereo track on disc in most cases, however some BD's and most UHD BD's don't have a stereo mix now.


JSmith

 

[clearnfc]

IMHO, there is no point focusing on audio quality for movies (i assume films = movies). A few reasons why i said that:

1. Main focus on audio in movies isnt quality but rather effects. On top of that, there is visual too! This means you are alot less likely to notice differences in audio quality while watching a movie. Its more important to get the sound effects right.

2. The sound in movies are not "real". "Real" as in actual sound recording during the filming. Most of the sound and effects you hear are added during post production. Eg. A scene showing a glass shattering upon hitting the floor. The sound you hear is usually taken from a library of pre-recorded sounds. Not the actual sound. Can you tell the difference? Probably not.

3. Most pple couldnt tell difference between MP3 and uncompressed audio. Yup, there are several tests conducted and many pple cant tell which is better. Many ended up thinking the MP3 one sounded better.

 

[Blumlein 88]

Atmos should be always superior, it’s the superior format of everything you mentioned.

I don't know. I think the Op is saying he has no Atmos capability, and yet stereo of AAC of Atmos tracks sounds different than AAC tracks. I find the same thing to be true. Obviously the mixdown differs as the original mch version is different in each case. And no Atmos isn't always the best sounding. It might be if Atmos were decoded, but not in a mixdown at all times.

 

[Blumlein 88]

IMHO, there is no point focusing on audio quality for movies (i assume films = movies). A few reasons why i said that:

1. Main focus on audio in movies isnt quality but rather effects. On top of that, there is visual too! This means you are alot less likely to notice differences in audio quality while watching a movie. Its more important to get the sound effects right.

2. The sound in movies are not "real". "Real" as in actual sound recording during the filming. Most of the sound and effects you hear are added during post production. Eg. A scene showing a glass shattering upon hitting the floor. The sound you hear is usually taken from a library of pre-recorded sounds. Not the actual sound. Can you tell the difference? Probably not.

3. Most pple couldnt tell difference between MP3 and uncompressed audio. Yup, there are several tests conducted and many pple cant tell which is better. Many ended up thinking the MP3 one sounded better.

Your list of three is a long way from confirming audio quality in movies has no point. In fact it is obvious there is a big difference in some movies vs others.

 

[Sancus]

I doubt there's any quality difference from the encoding type here. It's probably a mixing difference. Atmos in re-issues of older movies is usually a remix, probably from the original multitracks unless they were lost for some reason.

So in that case there's no "better" version for stereo listening, it's an arbitrary difference.

 

[abdo123]

I don't know. I think the Op is saying he has no Atmos capability, and yet stereo of AAC of Atmos tracks sounds different than AAC tracks. I find the same thing to be true. Obviously the mixdown differs as the original mch version is different in each case. And no Atmos isn't always the best sounding. It might be if Atmos were decoded, but not in a mixdown at all times.

The OP says he’s equipped with the necessary equipment.

 

[Blumlein 88]

The OP says he’s equipped with the necessary equipment.

knowing that I’m not equipped with the necessary equipment ? Quoted from the first post.

 

[abdo123]

knowing that I’m not equipped with the necessary equipment ? Quoted from the first post.

Sorry my bad.

 

[clearnfc]

Your list of three is a long way from confirming audio quality in movies has no point. In fact it is obvious there is a big difference in some movies vs others.

Perhaps you can show us evidence that there is indeed a difference and difference is due to lossy vs lossless.

I have not experience any improvement in audio quality on 2 channels. I do agree atmos sounds better than AC3 with proper setup but to me its due to better audio effects rather than audio quality.

Do note that my context of audio effects isnt the same as audio quality. Dolby surround, dts, atmos etc are effects to me.

 

[JSmith]

Many ended up thinking the MP3 one sounded better.

I'm humbly prepared to admit this... under testing I was able to discern a difference between FLAC and MP3, but was quite surprised when I had to pick which was which, I picked the 320 kbps MP3 the majority of the time as the "better" one. Testing like this can be very humbling and more people should do it... maybe they're afraid of what the results will say.


JSmith

 

[Blumlein 88]

Perhaps you can show us evidence that there is indeed a difference and difference is due to lossy vs lossless.

I don't see it as having anything to do with being lossy vs lossless. It is more like in regular music where you have different masters. The mix of Atmos with height channels and being object oriented audio is different than regular 5.1 channel mixes of Dolby Digital (AC3). First off if you have a base mix of 7.1.2 it isn't hard to see the mixdown to stereo is likely to be different than 5.1 mixdowns to stereo. In addition Atmos may have audio objects beyond the base channels (I think the correct term is bed channels) which will have to be mixed down.

I don't know how those mixdowns are done in our current AVR's or playback software, but they almost by definition have to be different than 5.1 to stereo mixdowns. I've not measured them, but having viewed some video of Atmos vs DD vs stereo they sound pretty obviously different. Atmos is sometimes better, sometimes not and mostly they simply differ. I could of course get two movies one Atmos encode, one DD encode, and play both in stereo and capture the results. I pretty well assume they will differ, and don't know that it will tell us which is better.

 

[clearnfc]

I don't see it as having anything to do with being lossy vs lossless. It is more like in regular music where you have different masters. The mix of Atmos with height channels and being object oriented audio is different than regular 5.1 channel mixes of Dolby Digital (AC3). First off if you have a base mix of 7.1.2 it isn't hard to see the mixdown to stereo is likely to be different than 5.1 mixdowns to stereo. In addition Atmos may have audio objects beyond that base channel (I think the correct term is bed channels) which will have to be mixed down.

I don't know how those mixdowns are done in our current AVR's or playback software, but they almost by definition have to be different than 5.1 to stereo mixdowns. I've not measured them, but having viewed some video of Atmos vs DD vs stereo they sound pretty obviously different. Atmos is sometimes better, sometimes not and mostly they simply differ.

Yes, i too dont see that lossy or lossless makes any difference in movies.

My reply is directly to TS. He was asking of the lossless audio of atmos is worth it since he doesnt have the appropriate gear. So, i am telling him there is no point and also explaining to him why lossless wont make any difference compared to lossy.

 

[abdo123]

I don't see it as having anything to do with being lossy vs lossless. It is more like in regular music where you have different masters. The mix of Atmos with height channels and being object oriented audio is different than regular 5.1 channel mixes of Dolby Digital (AC3). First off if you have a base mix of 7.1.2 it isn't hard to see the mixdown to stereo is likely to be different than 5.1 mixdowns to stereo. In addition Atmos may have audio objects beyond the base channels (I think the correct term is bed channels) which will have to be mixed down.

I don't know how those mixdowns are done in our current AVR's or playback software, but they almost by definition have to be different than 5.1 to stereo mixdowns. I've not measured them, but having viewed some video of Atmos vs DD vs stereo they sound pretty obviously different. Atmos is sometimes better, sometimes not and mostly they simply differ. I could of course get two movies one Atmos encode, one DD encode, and play both in stereo and capture the results. I pretty well assume they will differ, and don't know that it will tell us which is better.

Atmos does not have ‘bed’ channels. It’s completely object based and the 5.1 and 7.1 mixes that are included by default are simply for backward compatibility and serve no purpose at all once there is an Atmos renderer in the playback chain.

 

[kongwee]

Atmos does not have ‘bed’ channels. It’s completely object based and the 5.1 and 7.1 mixes that are included by default are simply for backward compatibility and serve no purpose at all once there is an Atmos renderer in the playback chain.

Atmos does have bed channels. https://professionalsupport.dolby.com/s/article/What-is-a-bed?language=en_US
For atmos mixing, who will wanna use bed channel as you can use immersive audio in friendly GUI.

 

[Offler]

@JSmith 'Death of Stalin' does have stereo track in LPCM, same for 'Man who killed Don Quixhote'.

In most cases I settled for Lossless formats, simply because they are usually 24bit 48kHz and only thing i need to do is to downmix audio to stereo. AC3 usually needs dithering, resampling ... much more work.

- I could not tell any difference when using my old Bose speakers
- with my current setup, lossless or uncompressed (LPCM) sounds a bit clearer..

Also in most cases i could not tell difference between lossless and AC3, with notable exceptions where bitrate was very low (eg. 192kb/s or less per channel), or when musical score was really integral part of the soundtrack (Cowboy Bebop, animated series).

 

[Sancus]

Atmos does have bed channels. https://professionalsupport.dolby.com/s/article/What-is-a-bed?language=en_US
For atmos mixing, who will wanna use bed channel as you can use immersive audio in friendly GUI.

You *can* use the bed channels in the Atmos mix but it's almost never done as I understand it. The only bed used is the LFE. Instead objects are used, and sometimes those objects mimic bed channels, but actual beds are not typically used. The embedded TrueHD(or DD+ for streaming) 7.1/5.1 tracks for backwards compatibility are separate.