Opinion: Dolby Needs to Bring Back Pro Logic / Pro Logic II / Pro Logic IIx / Pro Logic IIz

When Dolby introduced Dolby Surround … the new one for upmixing, not the 80s sound format – just the fact I need to clarify this shows there is something not quite right with this. Anyway, let’s start again.

When Dolby introduced Dolby Surround, they decided to drop all other legacy decoders from their licensing. So bye bye Dolby Pro Logic, Pro Logic II, IIx, IIz and Dolby Pro Logic (IIx) music modes.

I have a major problem with this. Firstly, it completely takes consumer choice away – for the sake of removing all complexity. But secondly, and this is the more pertinent point, it is a revisionist approach to movie and TV sound. Content mixed with Dolby Pro Logic, Pro Logic II or Pro Logic IIx / IIz in mind will NOT sound the same when played back through the new Dolby Surround Upmixer, and since these matrix steering technologies have been completely removed from AV receivers, there is no way to play back these soundtracks as originally intended by the content creators.

I find this rather baffling – especially coming from a company that is synonymous with movie sound. I am truly sorry, but I don’t want to have every 80s and 90s movie played back with the height channels active.

Dolby even went as far as removing the centre spread function from Dolby Surround at one point and even limiting Dolby Surround upmixing to Dolby Encoded soundtracks. Thankfully Dolby reversed these decisions so clearly they are willing to listen and change course.

And I do hope they will listen, because as it stands, I would need to keep two receivers running: one that has all the legacy decoders, and one for Dolby Atmos / Dolby Surround.

Request for Dolby and Receiver Manufacturers

Dear Dolby Labs! Please kindly make legacy decoders available as part of the Dolby Surround SDK and don’t leave such important legacy behind. There are a lot of us still listening to older movies and TV shows and would prefer to have the option of restoring the originally intended sound.

Alternatively, please introduce options for turning off height and surround back upmixing when relevant and re-introduce proper music modes into Dolby Surround with the centre spread function having a strength setting.

Dear Receiver Manufacturers – but especially Denon, Marantz and Yamaha! I am fully aware that bringing back legacy decoders can introduce complexity to the consumer. This is why I would recommend that you have the option within the menu system to turn legacy decoders on or off (either en masse or one by one). This way those that want to use them, can turn them on.

What About DTS Decoders?

DTS extensions such as 96/24, DTS ES Matrix / Discrete and so on are still available within the receivers. Their old upmixing technologies such as Neo:6 and Neo:X are gone. While I support their return as well, my opinion is that they are not necessary as there wasn’t content mixed specifically for them – which was NOT the case for Dolby’s upmixing technologies.


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13 thoughts on “Opinion: Dolby Needs to Bring Back Pro Logic / Pro Logic II / Pro Logic IIx / Pro Logic IIz

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  1. I found this article after upgrading my old Onkyo receiver to a new Yamaha. Some content doesn’t sound as good on the new receiver, which I believe is due to the lack of the Dolby Pro-logic modes on the new receiver.

    1. You can still use Dolby Surround but not while engaging CinemaDSP. That will engage Neo:6 for 2 and 5.1 channel sources.
      But yes, Dolby Pro Logic modes are missedโ€ฆ :/

  2. The reason Dolby ProLogic IL and llx are missing is Dolby is saving money by not having to pay the Fosgate Estate royalties for the technology invented by Jim Fosgate. It was a selfish business decision fooling folks with the gimmick of Atmos. Sound is alway better in the horizontal plane; not the ceiling.

    1. Thank you for that insight, Robert! It’s always about the money in the end, isn’t it? It is a real shame really, however good the new DSU upmixer is.

  3. +100

    I’m struggling to find a modern AV amp that provides DPLII natively.

    Its been 3 year that I wait to replace my old Yamaha RXV 579.

    1. Most modern receivers don’t have them both. The only one that did was the CX-5100 from Yamaha I believe. Do check, but I believe that can run both. None of the new receivers will however.

  4. You can actually turn off the height layer on DSU, at least on my Marantz 7012. That makes it behave considerably more like Pro Logic IIx here.

    However, my solution to older modes was to purchase a used Lexicon MC-1 and plug it into my Marantz 7012’s 7.1 inputs and use a Mini-DSP for subwoofer correction (You can have up to 4 subs and use MSO to get better results for multiple rows of seats than DIRAC DBLC, IMO).

    That way both the Marantz Atmos/DTS:X/Auro-3D modes and Lexicon Logic 7 and THX Pro Logic (including EX) modes get bass correction (I’m a firm believer in not correcting above Schroeder anyway) and so it all works out. I suppose Pro Logic II would be nice to have too, but I didn’t have enough rack space for a Lexicon MC-12 (Logic 7 is the really big draw; nothing beats it for 2-channel music upmixing. I suppose Auromatic is the next best modern thing, but it’s a little too tame in the surrounds, being mostly reverb copies).

    1. Thank you for that information, Magnus. That’s an interesting way to get Pro Logic IIx behaviour back. As you say it might sound more similar, but not sure if it’s the same. In any case, not a bad option. Thank you for sharing.

  5. There is only one very modern receiver (that I could find) with ProLogic 2 support. The Denon S670H though it’s “only” 5.1 so “only” ProLogic 2 and Neo:6 are supported. (other 5.1 receivers don’t even support these)
    I did my research and the lack of options made me realize that a simple 5.1 setup is good enough for a lot of cases (I don’t have a large cinema room)
    I mostly play Nintendo games so ProLogic 2 is for Mario Kart Double Dash and other Wii and Gamecube games and the Wii U and Switch are PCM 5.1
    ProLogic 1 is present in some super nintendo and n64 games
    2 front upfiring “atmos” speakers are kinda a waste of money and for proper height you would need an auro3d speaker layout. I don’t defend in ceiling except for the VOG channel
    also there is the auromatic upmixer which is a truly great upmixer though it requires very expensive receivers and if you have a 13.1 auro3d speaker layout you will love it
    (I tried it in a large room and yes you can play all your atmos tracks on it)
    from my research surround backs and height channels are kind not used a lot compared to 5.1 speakers (even in “atmos” movies that can use them) and since I’m mostly on Nintendo systems and PC the Denon S670H currently priced around Tree Fiddy is a very compelling offer.
    (yes it has e-arc 40gbps hdmi and 8K60 4K120 video output both with VRR so it’s near future proof)

    1. Yes, the other option was the Yamaha CX-A5100 I believe which retained both. However, you need an external amp for that. It’s not a huge deal, ultimately, but I don’t like them dropping old decoders and would be good for Dolby to include the old decoders into the new licences instead of completely getting rid of them in the market.

      Yes, 5.1 is still good if you set it up right… ๐Ÿ˜‰

  6. I miss Dolby PL IIz on my current. The Dolby surround on current Denon 3500H other newer models doesnโ€™t have the same upmix qualities. DTS X with Audyssey dynamic EQ helps me a little. Previous models I had were AVRX3000 and Onkyo TX-NR616. I also tried AVR-2300w ghosts same as current generation lacking PL and NEO. Bring back PL.

  7. I upgraded my Yamaha RX-A3000 to an RX-A6A a few months ago. Having had Dolby Surround back in the 80s, it baffled me at first that the only Dolby mode was just called Surround after having had all the newer iterations in between.

    I really enjoyed DPLIIx Movie and Music on a 7.2 setup. Now I use the new Dolby for music, but am more excited by Yamahaโ€™s AI DSP for movies. Not quite sure 2 channel stereo music sounds as good as it did with DPLIIx Music

    1. Yes, the new mode being called Dolby Surround is bizarre. But itโ€™s what it is. Glad Surround AI is working great for you, though.

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