Dolby Surround (2014) vs Dolby Pro Logic II

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paulisdead

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May 1, 2004
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I've been trying to find answer to this one, so I'll throw it to the forum:

What is the difference between Dolby Surround (the 2014 incarnation) and Dolby Pro Logic II in terms of channel placement? I'm thinking of buying a new AV receiver and most are now Dolby Surround only.

Also, how well does Dolby Surround (2014) decode older VHS/DVD/LD content recorded in Dolby Surround?

Has anyone here had any experience with this?
 
Not sure how to answer your question, but Dolby Surround upmixes to the maximum speaker arrangement on my system: 7.2.4.
It sounds ok!

Thanks. I guess what I'm wondering is - if I played Dolby Surround (traditional) encoded content though a Dolby Surround (2014) receiver with 5.1, would it sound the same (i.e. same image placement, etc) has if I was to play it through a Dolby Pro Logic II receiver 5.1.
 
I found this:

https://www.soundandvision.com/content/meet-new-dolby-surround#iAMX0eASqPbUbwif.99
Dolby Pro Logic and its descendants have side-to-side and front-to-back adjustments. Does Dolby Surround work the same way?

There is a Center Spread control (optional to implement by manufacturer) that is designed to spread the center image into the L and R mains. Like the Center Width control of Pro Logic, it is designed to complement musical content, or can be used by consumers who have a very wide screen display and want to spread the dialogue more evenly across the screen.

Why no front-to-back control?

The new algorithm we employ for Dolby Surround does a better job of extracting and separating elements of the mix—including ambient content—and distributing them evenly throughout the soundstage. Hence there is less need for controls that were inherent to a wideband algorithm.

What is going to happen with the existing Pro Logic family, such as Pro Logic II, IIx, and IIz?

As part of the Dolby Atmos bundle, Dolby Surround is a total replacement of Pro Logic. However, we are still licensing Pro Logic family. You will see it in non Dolby Atmos equipped AVRs. A manufacturer could also choose to include Pro Logic family as a complement to their licensed Dolby Atmos technology bundle, and in fact Onkyo and Yamaha are including it in their Dolby Atmos receivers.

The decision to resurrect the old Dolby Surround moniker seems confusing, at least to people who recall the old analog Dolby Surround. Why this, why now?

Yes, you and I remember the first generation analog—but this is not an extension of that technology! The decision to call it Dolby Surround was based on the fact that we are trying to make our technologies and what they do more understandable. A simple product name works best here, and given that the new format is compatible with a variety of speaker configurations from 5.1 to 24.1.10, it made sense to have a simple and direct nomenclature. We thought Dolby Surround is a name people can associate with and thus it made sense.
 
This won't fully answer your question but I can offer this:

I replaced a Yamaha AVR with Dolby PLii Music with a newer Yamaha AVR that has Dolby Surround. I don't like the new version as well. It doesn't have the same controls for parameters for things like "panorama" and "dimension" and I don't think it upmixes 2 channel signals as well. The surrounds are not as active nor as loud. I have to turn them up much louder to get anything close to the same effect.

As far as how it handles encoded content, I can't tell you as I don't play enough of that to compare. But my guess is it won't be exactly the same for the reasons stated about.

It may also be a Yamaha thing (other brands may still have the controls features?).
 
This won't fully answer your question but I can offer this:

I replaced a Yamaha AVR with Dolby PLii Music with a newer Yamaha AVR that has Dolby Surround. I don't like the new version as well. It doesn't have the same controls for parameters for things like "panorama" and "dimension" and I don't think it upmixes 2 channel signals as well. The surrounds are not as active nor as loud. I have to turn them up much louder to get anything close to the same effect.

As far as how it handles encoded content, I can't tell you as I don't play enough of that to compare. But my guess is it won't be exactly the same for the reasons stated about.

It may also be a Yamaha thing (other brands may still have the controls features?).

It kind of has, thanks. I'm used to playing my stereo film on PLII Movie mode and I've noticed that it decodes older movies that were Dolby Stereo in the theatres quite nicely.
 
It kind of has, thanks. I'm used to playing my stereo film on PLII Movie mode and I've noticed that it decodes older movies that were Dolby Stereo in the theatres quite nicely.

That's good to know.

I played a "Dolby Surround" CD the other day and I thought it sounded fine. Really, the only thing I use it for is upmixing the music I play streaming from Pandora which is usually light jazz. The old version gave me a nice full surround with stuff in the rears that sounded discreet. The new version doesn't do it nearly as well. A lot of that probably has to do with the low-res signals coming from the Pandora stream. But it definitely handles the signal differently.
 
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I played a "Dolby Surround" CD the other day and I thought it sounded fine.

These tend to be overlooked, and some of them are really good! This is one of my favorites.

However, these are encoded in the original Pro Logic system, not PLII, which I believe means they were mixed with wide stereo in the fronts and mono rears. I have an early Pro Logic Decoder (AudioSource SS-3) in my setup and it only has three balance controls: FL, FR, and Rear Center.

Most of Tomita's quad titles were reissued as Dolby CDs in the early 90s. I think these are simply the quad mixes with the rears summed to mono.
 
I've been trying to find answer to this one, so I'll throw it to the forum:

What is the difference between Dolby Surround (the 2014 incarnation) and Dolby Pro Logic II in terms of channel placement? I'm thinking of buying a new AV receiver and most are now Dolby Surround only.

Also, how well does Dolby Surround (2014) decode older VHS/DVD/LD content recorded in Dolby Surround?

Has anyone here had any experience with this?

There are some big differences.
Pro Logic II has Stereo Surround Channels that are not bandwidth limited while Dolby Surround had a mono Surround Channel limited to 7 kHz.

Some interesting articles on the development of Pro Logic II by matrix surround pioneer/guru Jim Fosgate:

1204fos.1.jpg


https://www.quora.com/How-is-Dolby-Pro-Logic-II-compared-to-Dolby-Pro-Logichttps://www.stereophile.com/interviews/1204fosgate/index.html
 
These tend to be overlooked, and some of them are really good! This is one of my favorites.

However, these are encoded in the original Pro Logic system, not PLII, which I believe means they were mixed with wide stereo in the fronts and mono rears. I have an early Pro Logic Decoder (AudioSource SS-3) in my setup and it only has three balance controls: FL, FR, and Rear Center.

Most of Tomita's quad titles were reissued as Dolby CDs in the early 90s. I think these are simply the quad mixes with the rears summed to mono.
The only one I have is a CD by Adrian Legg which is mostly solo guitar anyway. So it’s kind of hard to tell if it’s “right”. Or not. Sounds fine though!

I think I’ll look for that Spies disc though. I remember hearing that back in the day and liking it!
 
There are some big differences.
Pro Logic II has Stereo Surround Channels that are not bandwidth limited while Dolby Surround had a mono Surround Channel limited to 7 kHz.

That was true with original Dolby Surround versus Pro Logic II, but it sounds as though Dolby has re-labelled Pro Logic II back to that earlier moniker. I'm not up to date on today's
latest Dolby capabilities, but I expect that they've kept some of the surround channels stereo in configurations larger than 7.1, but some of those expanded channels may be mono.
 
I too would be interested in hearing any in-depth review of the new (Atmos upmixing) Dolby Surround decoding process, strictly as 5.1 upmixing from Dolby Stereo to keep such comparisons tp DPL2 "apples to apples" so to speak. I'm pretty sure they've kept the DPL2 channel decoding channel parameters intact, as those encode/decode parameters have gained their spots in the market. But if new logic algorithms are used, how is the various decoding performance parameters in areas that we here would care about? How is center channel decoding? Is it superior to DPL2? Or worse? How is decoding when torture test material is used? Are there fewer steering artifacts, or more? How is fidelity compared to older DPL2 decoding? Does it indeed stay 100 % true to the DPL2 matrix configuration?
 
There are some big differences.
Pro Logic II has Stereo Surround Channels that are not bandwidth limited while Dolby Surround had a mono Surround Channel limited to 7 kHz.

Some interesting articles on the development of Pro Logic II by matrix surround pioneer/guru Jim Fosgate:

1204fos.1.jpg


https://www.quora.com/How-is-Dolby-Pro-Logic-II-compared-to-Dolby-Pro-Logichttps://www.stereophile.com/interviews/1204fosgate/index.html
It's interesting that Fosgate didn't mention the two surround processors he offered for car stereo use. The "Gavotte", the first model, was a high-separation model that offered a dash-mounted level control for the rear channels. The "Gavotte II" had separate front and rear inputs, and could allow a head unit with four channel pre-outs to adjust front-rear balance via the head unit's fader control. I had experience with both units, and would love to find another Gavotte II for my current vehicle.
 
I'm not happy with Dolby Surround (the 2014 technology, not the much older Dolby tech with the same name) Upmixing (DSU) , I prefer DPLIIx/z....which seems now to be 'retired.' :<

Ways in which DSU differs from DPLII, by Roger Dressler, who helped design DPLII and knows its workings intimately:

https://www.avsforum.com/forum/19-d...dwood-theater-comes-alive-7.html#post29237489
Basically to me DSU seems really geared towards upmixing movie soundtracks. 2-ch music upmixing seems an afterthought.
 
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Thanks for sharing the link to Roger's 1st evaluation of DSU decoding. Many interesting tidbits there, including noting the DSU being a multi-band decoder. And it does sound like the the core matrix decoding did have some subtle changes. Key, as decorrelated material can be found in a number of both Dolby Stereo tracks and stereo music. Hmmm......

(Over the years even when at Dolby, Roger Dressler has always been very open in forums and private emails about discussing the pros and cons of their various formats, which is refreshing.)
 
Does it matter whether it's Dolby Surround Music or Movie? My AVR has several options for Dolby Surround. Also, somewhat related, what are opinions on DTS Neural X for upmixing audio?
 
I'm trying to determine that myself. My newer Denon 's remote has Movie and Music and Game buttons. But pressing them shows a menu of different upmixing algorithms (Dolby Surround, DTS Neo, etc) .

In my older Denon. DPLII had its own *separate* Music, Movie, Game settings. They were different modes of DPLII . E.g within DPLII 'Music' mode there were settings that were not available in DPLII 'Movie'. The DTS upmixer had none of this.

I don't see that in the new Denon. Dolby Surround only ever offers one changeable parameter, 'Center Spread', regardless of Music/Movie/Game. So what I think maybe the new Denon does is simply offer whatever upmixers it has available, and lets the user pick based on what they are listening to. In other words, Dolby Surround 'Movie' is no different from Dolby Surround 'Music'.

But I'm still investigating. Could be wrong.
 
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