Has anyone been able to define well or measure differences between vinyl and digital?

I think it is the physics of analog crosstalk of the cartridge :)

Ps Audio recently posted on this very topic. Perhaps the answers you seek are contained within Paul’s posts. 

"An album with DR 6 doesn't necessarily sound overtly bad. And an album with DR 12 doesn't necessarily sound good (but the DR isn't to be blamed at least). For rock/metal a DR of 8 and above is considered okay. Electronic music can still sound okay with DR 5 because it is less dense."

Ref: https://dr.loudness-war.info/faq

It therefore seems the differences are mainly academic in the same way as ASR tests hardware.

If you don't like listening at 90dB then something with higher compression might even sound better. Indeed the average person seems to listen around 70dB for comfort.

Is the impact of 2 channel speaker systems equal for either source?

Regarding Atmos as a multi source format, I wonder how robust it is vs say binaural recording playback. My impression also is that Auro3D is more ‘immersive’ and therefore more accurate in capturing natural environments. 

Oth ambiophonics offers another method of playback that reveals the power of certain types of immersive systems.

Ambiophonics reference

@johnread57,

We are in the early days of ATMOS and Auro3D. I have heard some bad recordings and some exceptional ones. I think it will be difficult to find a sweet spot with users, most will not put in that many speakers. In theory the object oriented nature of ATMOS takes this into account, but my gut is it may be difficult to translate recorded live events with multiple microphones to a different speaker array. Of course, where all the speakers get a signal manufactured for them through mixing, then it likely will work fine.

These formats on headphones will be popular far before they are for speaker systems.

Can you imagine the remixes from older material? Scary!

I do not know what you mean is the image of 2 channel speaker systems equal?