So I have never seen this exact question answered.  When using an Xbox to watch DTS or DTS:X blu rays, which is the better output setting: LPCM 5.1, or Atmos?  

So far as I can tell (from lots of googling)  when transcoding to Atmos Xbox appears to just be putting the LPCM streams into a Dolby MAT container and not compressing them, then adding Atmos metadata. I’m presuming you’d lose any height channel information from DTS:X so the metadata would ordinarily be null, but if you have Atmos upmixing turned on you might get some improvements to the soundstage.  So minor advantage Atmos, I’d think.

Curious whether anyone else has thought about it.