Unfortunately, as I wrote about this before, legacy Pro Logic / Pro Logic II / Pro Logic IIx / IIz Decoders have to be removed from Dolby Atmos enabled receivers. The only surround decoder / upmixer that is included is the new Dolby Surround upmixer.
Unfortunately, this has an unintended consequence on Yamaha receivers. When engaging any of the Cinema DSP modes with two-channel or 5.1 channel sources, the DTS Neo:6 decoder is used to upmix the channels to 7.1 surround sound before CinemaDSP is applied. I don’t know about you but I have never been a huge fan of DTS Neo:6 as compared to Dolby Pro Logic IIx.
When Can You Do?
You have two choices:
- Put up with Neo:6 for 2-channel and 5.1 channel expansion before CinemaDSP is applied
- Use the Surround Decode function to switch to plain Dolby Surround upmixing without CinemaDSP for 2-channel and 5.1 channel mixes
Please note that 7.1, Atmos and DTS:X mixes are not affected. However, 7.1 mixes will not be unmixed to all speakers, they will simply have CinemaDSP applied so again you will need to choose between upmixing and CinemaDSP.
Possible Solutions Yamaha Could Implement
The best solution would be for Yamaha to enable the Dolby Surround decoder to be used for upmixing before CinemaDSP is applied. Of course Dolby’s new Dolby Surround upmixer is computationally much heavier than the old Pro Logic decoders.
The other option would be to ask Dolby for an exception in this case and allow the Dolby Pro Logic IIx decoder to be used only under CinemaDSP. I understand they may require disabling it on the main interface so that users don’t accidentally select it instead of the new upmixer. However, in this case, the option is hidden quite down in the interface to cause much issue.
Related Professional Guide
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