Well, for one, the original decoder had a frequency limit on the rears, so if you hear any high amount of clarity and brilliance from the rear speakers, that's not 100% accurate likely. Other than that ... just hold the rear speakers to both your ears and turn down the volume and see if you hear differences/inequality.

(2020-05-25, 05:23 PM)TomArrow Wrote: Well, for one, the original decoder had a frequency limit on the rears, so if you hear any high amount of clarity and brilliance from the rear speakers, that's not 100% accurate likely. Other than that ... just hold the rear speakers to both your ears and turn down the volume and see if you hear differences/inequality.

That is precisely what I've been doing, but the trouble is I don't know of any particular film (or bit of a film) that uses the surround channel heavily enough to test with and have some certainty about.

I've been wandering about the living room at intervals switching DSP modes and audio tracks and sticking my ear to speakers for days; I reckon my partner thinks the lockdown has finally broken me.

How about creating your own test file for this purpose?

(2020-05-25, 06:25 PM)TomArrow Wrote: How about creating your own test file for this purpose?

I guess, but surely I'd need to be able to reliably encode from 4 channels to 2 with the old Pro Logic algorithm and the only way I know how to do it currently is using eac3to which uses Pro Logic II (separate surrounds, not mono). I don't presently have access to an official version of the Dolby encoder, which is what I assume I'd probably need for this. (Maybe even a legacy version of it?)

It used to be with PLII that you could choose the mode (there was PLII 'Movie' and 'Music' mode, plus original PL with the band-limited mono surround). I was always so impressed with how the split rears were decoded on PLII that I used it almost all the time (especially with LD PCM tracks, this was before I got an RF Demodulator), the only times I used Pro-Logic is if I was feeling a bit 'particular'. Even with Gamecube games which used PLII I could never get the encoding to 'fail' so to speak, something to do with cues embedded in the L/R channels. 
If it's important for you to playback in original Pro-Logic (and this is not possible with your Atmos AVR) then you still have options, they are all somewhat convoluted though

I'm still looking for a software pro logic decoder to convert my Dolby surround LD.
I can't find a surcode pro logic decoder for upmixing the 2.0 matrix, into 5.1 / 4.0 / 3.0 ...

BTW, my surcode pro logic that I use to convert 5.1 to 2.0 to complete my LD (when the intro logo is different of the blu ray for example), clipping all my tracks

A few (dumb?) questions, if you don't mind:

How do you connect a modern bu ray player to a Shure HTS? Also, if you input a lossless stereo (PCM, DTS-HD MA), is it also a lossless surround on the output?

Sorry, a total newbie about this here

Also, is DTS: Neo 6 supposed to be the next best thing to Acra-Vector technology used in Shure HTS?

Disclord had this to say about it: DTS:Neo-6 was designed to decode Dolby Surround encoded films and DTS never made an encoder for it - Neo-6 is much more accurate in decoding Dolby Surround than Pro Logic or PL II because it breaks the spectrum up into 12-20 bands and decodes each band separately, which allows simultaneously dominant sounds to be decoded and placed in their proper channel wi no leakage of unwanted sounds or pulling non-dominant sounds towards the dominant ones. Pro Logic can only decode one dominant sound at a time and PL II is the same since both are broadband logic steering designs.

Interesting.

About the lossless stereo ... I'm not sure what exactly you're asking, but it depends surely if the stereo is just normal stereo or surround. This is indicated by a flag in the codec I think. If it's normal stereo, it will come out as stereo too unless the decoder ignores that.

(2020-05-27, 04:25 PM)TomArrow Wrote: Interesting.

About the lossless stereo ... I'm not sure what exactly you're asking, but it depends surely if the stereo is just normal stereo or surround. This is indicated by a flag in the codec I think. If it's normal stereo, it will come out as stereo too unless the decoder ignores that.

Sorry, maybe I'm formulating this totally wrong  My question was if the matrix signal you feed to that particular decoder is lossless (for example. DTS HD-MA), does it come out lossless as well, when decoded?