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.

4 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 missed… :/

  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.

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