Upmixing - where are we at? Have people compared upmixers?

[KMO]

Adjusts how much of the common L/R signal is routed to the center during upmixing.

Standard Pro Logic or Pro Logic II Movie or Dolby Surround upmix will send a mono signal entirely to the centre speaker.

They're maximally steering - they're trying to pinpoint sound positions.

This is optimal for processing a Dolby Surround-encoded signal, to try to reproduce an original 5-channel mix. It means a Dolby Digital downmix-then-upmix does not differ much. But it's not ideal if you're working on non-Dolby encoded music content. Stuff tends to collapse to the centre too much, reducing the spaciousness.

Pro Logic II Music has a "centre width" control that changes where the centre signal goes to. At "0" it goes entirely to the centre, at "7" it goes entirely to L+R, and the default is "3", which sends it to all of them. (With a 2ms delay on the centre, apparently, for some psychoacoustic reason).

Dolby Surround has a similar on/off "centre spread" control. This briefly vanished in some firmware, but was restored, as noted above. I believe it's similar to the default "3" in PLII Music, but without the 2ms delay.

Pro Logic II Music has two other more obscure controls "dimension" and "panorama" which aren't available in Dolby Surround. "Dimension" is some sort of front/back balance (very subtle), and "panorama" is an option to route non-surround L and R to surround speakers. (So the isolated L component would go to L+Ls+Lrs, rather than just L, for example.) This effectively wraps the left-to-right non-surround soundstage around you, rather than having it in front of you.

 

[KMO]

I could not hear the distortion this someone mentioned. This does not match what I measured or what Archaea on AVS measured.

The bug is discussed here:

Sound leaking into surrounds (voice)

Hope someone can help as am sure something is ‘wrong’ with my Denon 4700 but maybe it’s something else happening I have noticed for a while that when watching normal programming on Sky the vocals are coming through the surround and also front L and R but more of a problem in the surrounds...

www.avforums.com

And apparently there has been a fix in recent firmware for at least some models.

(Although I suspect complaints may linger, because once people start listening for leakage, they're going to hear it. Upmixers have always had some channel leakage, so if you stick your ear against a surround, you're going to hear weird noises. But the bug was apparently clearly objectionable bleed from normal listening position.)

 

[Sancus]

The very thing that helps Neural X with movies is the very thing that hurts it with music. It's 3D steering activity. It works extremely well with movies but tends to move things unnaturally with music.

I did end up trying Neural X with TV/Movies and I was pretty impressed. You are correct, it's clearly the best algorithm for that. Unfortunately when it's turned on for Dolby Surround on a Denon, that also means the AVR forces it on for Atmos content, which I don't want. So now I have to manually switch back and forth based on the content, sigh.

 

[JonK99]

Standard Pro Logic or Pro Logic II Movie or Dolby Surround upmix will send a mono signal entirely to the centre speaker.

For a simple demonstration try listening to any number of older mono jazz recordings. All you get is center. Before I discovered the center spread I found the upmixer unusable as I have many playlists that include older and newer material and I couldn't stand the single-speaker effect whenever an older recording came on. Now with center spread I just leave the upmixer on all the time. It's certainly not perfect, especially when compared to natively mulit-track recordings, but on balance I'd rather have 9 speakers playing rather than just 2.

 

[KMO]

Yes, I almost exclusively use Pro Logic II Music for 2-channel music.

But to use Dolby Pro Logic II Movie for that, or Dolby Surround without centre spread, would indeed be unthinkable.

Which is why the removal of the centre spread option was utterly bonkers. To actually reach the point of that being deployed suggests something has gone gravely wrong at Dolby since the days of PLII development/acquisition.

I guess Pro Logic II wasn't really a Dolby thing in the first place, being Jim Fosgate's labour of love to make something that would work effectively for arbitrary music as well as deliberately-matrix-encoded stuff.

Dolby themselves never really cared about that.

 

[Soundmixer]

The bug is discussed here:

Sound leaking into surrounds (voice)

Hope someone can help as am sure something is ‘wrong’ with my Denon 4700 but maybe it’s something else happening I have noticed for a while that when watching normal programming on Sky the vocals are coming through the surround and also front L and R but more of a problem in the surrounds...

www.avforums.com

And apparently there has been a fix in recent firmware for at least some models.

(Although I suspect complaints may linger, because once people start listening for leakage, they're going to hear it. Upmixers have always had some channel leakage, so if you stick your ear against a surround, you're going to hear weird noises. But the bug was apparently clearly objectionable bleed from normal listening position.)

I've had the X3700 and the X6700 (currently as a pre-pro), and have never heard any dialog leakage into the surrounds. I do agree with one poster who said once you hear something like this, you cannot unhear it. This would be VERY noticeable to me.

 

[Dj7675]

I've had the X3700 and the X6700 (currently as a pre-pro), and have never heard any dialog leakage into the surrounds. I do agree with one poster who said once you hear something like this, you cannot unhear it. This would be VERY noticeable to me.

When Denon/Marantz first released a firmware to upmix via DSU to wides, it was very evident. It has since been fixed for the most part. It only shows up (if I recall correctly) when using DSU on stereo material. It was very well documented in the Denon X8500 thread on AVS. I had the X8500 and could hear it in surrounds for sure. On stereo material, I just started to us DTS:X to upmix stereo instead.

 

[Soundmixer]

When Denon/Marantz first released a firmware to upmix via DSU to wides, it was very evident. It has since been fixed for the most part. It only shows up (if I recall correctly) when using DSU on stereo material. It was very well documented in the Denon X8500 thread on AVS. I had the X8500 and could hear it in surrounds for sure. On stereo material, I just started to us DTS:X to upmix stereo instead.

Interesting. If it was so evident, why didn't I hear it on my AVR's? Was this unique to certain models, or supposedly across all AVR lines?

 

[Dj7675]

Interesting. If it was so evident, why didn't I hear it on my AVR's? Was this unique to certain models, or supposedly across all AVR lines?

Here is a link from Denon.

Error

support.denon.com

Also referenced here on AVS (see number 25)

https://www.avsforum.com/threads/official-2020-denon-avr-owners-thread-faq-posts-1-8.3151088/

It only happened with stereo upmixing.

 

[KMO]

I did end up trying Neural X with TV/Movies and I was pretty impressed. You are correct, it's clearly the best algorithm for that. Unfortunately when it's turned on for Dolby Surround on a Denon, that also means the AVR forces it on for Atmos content, which I don't want. So now I have to manually switch back and forth based on the content, sigh.

Really? How does it do that? Does it stop deliberately ignore the Atmos to get the compatibility base layer, then apply the Neural:X, so it's "Dolby Digital Plus + Neural:X" or "Dolby TrueHD + Neural:X"? That seems spectacularly unhelpful.

I can see that they might want some option to ignore the Atmos and play the base layer, but that seems like a really annoying UI.

The manual sensibly says of "Dolby Digital Plus + Dolby Surround" "*7 This can be selected when the input signal does not contain Dolby Atmos.", but they've not applied that logic to Neural:X for some reason. Surely Neural:X should function exactly the same way as Dolby Surround?

DTS NEO:6 and Dolby PLII work sensibly in my older Denon AVR - it just remembers which upmixer (if any) you last used for a particular upmixable format, and applies it again next time.

 

[EEE272]

Really? How does it do that? Does it stop deliberately ignore the Atmos to get the compatibility base layer, then apply the Neural:X, so it's "Dolby Digital Plus + Neural:X" or "Dolby TrueHD + Neural:X"? That seems spectacularly unhelpful.

I can see that they might want some option to ignore the Atmos and play the base layer, but that seems like a really annoying UI.

The manual sensibly says of "Dolby Digital Plus + Dolby Surround" "*7 This can be selected when the input signal does not contain Dolby Atmos.", but they've not applied that logic to Neural:X for some reason. Surely Neural:X should function exactly the same way as Dolby Surround?

DTS NEO:6 and Dolby PLII work sensibly in my older Denon AVR - it just remembers which upmixer (if any) you last used for a particular upmixable format, and applies it again next time.

I am quite sure that my Yamaha does the same. If you choose the surround format upmixer Neural X, anything that comes in is transformed to the base layer and then uplifted - maybe except for DTSX. Just like the Dolby Upmixer does seem to accept Atmos. But there is a button on the remote for switching back to straight or one of the DSPs, which reactivates support for Atmos.

 

[Dj7675]

Really? How does it do that? Does it stop deliberately ignore the Atmos to get the compatibility base layer, then apply the Neural:X, so it's "Dolby Digital Plus + Neural:X" or "Dolby TrueHD + Neural:X"? That seems spectacularly unhelpful.

I can see that they might want some option to ignore the Atmos and play the base layer, but that seems like a really annoying UI.

The manual sensibly says of "Dolby Digital Plus + Dolby Surround" "*7 This can be selected when the input signal does not contain Dolby Atmos.", but they've not applied that logic to Neural:X for some reason. Surely Neural:X should function exactly the same way as Dolby Surround?

DTS NEO:6 and Dolby PLII work sensibly in my older Denon AVR - it just remembers which upmixer (if any) you last used for a particular upmixable format, and applies it again next time.

Atmos cannot be upmixed by Neural:X.

 

[Soundmixer]

Here is a link from Denon.

Error

support.denon.com

Also referenced here on AVS (see number 25)

https://www.avsforum.com/threads/official-2020-denon-avr-owners-thread-faq-posts-1-8.3151088/

It only happened with stereo upmixing.

Considering I stream Youtube pretty much every day which is strictly 2 channel stereo, I should have heard this dialog leakage. Dialog leakage as I have said previously is pretty difficult to ignore, especially in a nearfield system where all of the 7 lower-level speakers are only 5.5 ft away.

Atmos cannot be upmixed by Neural:X.

If Neural X is used for two-channel sources, when Atmos is engaged, the AVR will revert to the 7.1 core and upmix using the Neural X upmixer. Atmos can't be upmixed, but the core 7.1 lossless bed can.

 

[Oniiz86]

The bug is discussed here:

Sound leaking into surrounds (voice)

Hope someone can help as am sure something is ‘wrong’ with my Denon 4700 but maybe it’s something else happening I have noticed for a while that when watching normal programming on Sky the vocals are coming through the surround and also front L and R but more of a problem in the surrounds...

www.avforums.com

And apparently there has been a fix in recent firmware for at least some models.

(Although I suspect complaints may linger, because once people start listening for leakage, they're going to hear it. Upmixers have always had some channel leakage, so if you stick your ear against a surround, you're going to hear weird noises. But the bug was apparently clearly objectionable bleed from normal listening position.)

Well Dolby have not really "fixed" it per se, it is just different for whatever reason, I believe the reason it became spoiled was because of the addition of their Atmos Height Virtualizer which became apart of their Atmos/DSU Dolby Home Audio v1.6.2 SDK first implemented on D+M AVRs back in August 2019, the way Dolby's implementation of this virtualizer unlike DTS' variant Virtual:X which is a separate sound mode must have disrupted the code somehow & it can no longer be how it once was, this is what Dolby had said to Sound United regarding the latest D+M firmware update with the latest Atmos/DSU decoder v1.6.3 SDK, "the resolved firmware is not identical to the older (pre-dialog bleed issue) version from Dolby so depending on the content, it might still be heard although at much lesser degree. And that this is the best that Dolby can do with this decoder version."

 

[Beershaun]

Audioholics just posted another video on this topic with in room measurements.

 

[Archaea]

I could not hear the distortion this someone mentioned. This does not match what I measured or what Archaea on AVS measured.

certainly false.

https://www.avsforum.com/threads/why-you-might-like-auro-2d-for-music-upmixing-what-is-going-on-behind-the-scenes.3169754/

 

[Archaea]

The bug is discussed here:

Sound leaking into surrounds (voice)

Hope someone can help as am sure something is ‘wrong’ with my Denon 4700 but maybe it’s something else happening I have noticed for a while that when watching normal programming on Sky the vocals are coming through the surround and also front L and R but more of a problem in the surrounds...

www.avforums.com

And apparently there has been a fix in recent firmware for at least some models.

(Although I suspect complaints may linger, because once people start listening for leakage, they're going to hear it. Upmixers have always had some channel leakage, so if you stick your ear against a surround, you're going to hear weird noises. But the bug was apparently clearly objectionable bleed from normal listening position.)

I have a launch Denon X6700. It's in the first few hundred off the line by the serial number, which I posted in the Denon x6700 review thread, but can't recall the exact number and don't care enough to go find it.
I've listened to Dolby Surround upmixing 90% of the time for music since launch on this unit. Distortion and oddities from the surrounds, rears and heights has never been true for my Denon x6700 using Dolby Surround. The Dolby Surround has been excellent since day 1, and I quickly adopted it over standard stereo for my preferred upmixer of two channel music.

Though I would say this kind of thing (odd or unwelcome noise or voice placements) is something I HAVE noticed with the DTS Neural X upmixer with two channel music, and worst still with mono sound tracks on old 1950s movies. I’ve had surround speakers blare at me startlingly with DTS Neural X upmixes. Orchestra music that comes out of unnatural speakers etc. I’ve never experienced this with Dolby Surround.

I wonder if this is more related to people who use Audyssey Dynamic EQ which boosts the surrounds preposterously at low volumes. If that's enabled and at low volumes - you are probably getting lots of weird things on any of the upmixers.

 

[Miker 1102]

I see someone commented on that Youtube video with this:



Rumor or truth?

I don't like the way Denon's mix sound at all. I wonder if this is true? As stated, Aura 3d, 2d are to bass heavy and the roll off of the high frequency sounds really anemic to me. I prefer my cheaper Sony to the Denon for processing music any day of the week. This is with a target curve adjusted in Audyssey.

 

[Miker 1102]

Well Dolby have not really "fixed" it per se, it is just different for whatever reason, I believe the reason it became spoiled was because of the addition of their Atmos Height Virtualizer which became apart of their Atmos/DSU Dolby Home Audio v1.6.2 SDK first implemented on D+M AVRs back in August 2019, the way Dolby's implementation of this virtualizer unlike DTS' variant Virtual:X which is a separate sound mode must have disrupted the code somehow & it can no longer be how it once was, this is what Dolby had said to Sound United regarding the latest D+M firmware update with the latest Atmos/DSU decoder v1.6.3 SDK, "the resolved firmware is not identical to the older (pre-dialog bleed issue) version from Dolby so depending on the content, it might still be heard although at much lesser degree. And that this is the best that Dolby can do with this decoder version."

Great information.

 

[Soundmixer]

I've listened to Dolby Surround upmixing 90% of the time for music since launch. This has never been true for my Denon x6700. The Dolby Surround has been excellent since day 1, and I quickly adopted it over standard stereo.

I totally agree with you on this. DSU's goal is to subtlety enhance what is in the stereo mix without spatially changing anything.

Though I would say this kind of thing (odd or unwelcome noise placements) I've noticed with the DTS Neural X upmix

Neural X is not optimized for two-channel sources based on how the upmix algorithm handles it. It is optimized for 5.1 and 7.1 film and music content based on how it operates.

I wonder if this is more related to people who use Audyssey Dynamic EQ which boosts the surrounds preposterously at low volumes. If that's enabled and at low volumes - you are probably getting lots of weird things on any of the upmixers.

This is something one should explore. The other thing to look at is how Sky handles the audio throughout its cable and broadcast chain from front to back. Any phase abnormalities (splattering) happening within that chain with stereo signals can surely upset the decoding of a matrix algorithm like DSU. Add DEQ into that equation, and it would sound like a spatial mess.