What model TV and Blu-ray player do you have? What Sonos sound bar are you using?

LG CX OLED

Sony UBP-X700

Beam Gen 2

Sub mini

Dolby atmos seems to work fine?

The LG CX doesn’t support DTS pass through. But you can set the Digital Audio Output setting on the Blu-ray player to PCM and get lossless Multichannel PCM audio from all DTS-encoded Blu-rays.

FYI… Sonos does support DTS Digital Surround but not DTS-HD Master Audio or DTS:X.

I have the same setup as the OP except that I have a Sony A75L.

I have spent some time trying to get the best audio for my DTS Blurays (mostly Christopher Nolan movies) and I think the PCM decoding does not quite get everything right, whether in the Bluray player or through a ripped file in a computer using the ffmpeg software (and then playing back through the Bluray player using USB). I think the bass tone is cleaner in PCM but the relative volumes of all the channels feels off. At the very least, the PCM decoded audio needs the volume turned up. In the end, the DTS core played by Sonos sounds better to me. Is there a trick to get the PCM decoding done right in the X700 or through ffmpeg?

It will be nice if Beam Gen 2 can get the license for DTS HD MA and DTS:X. Sony Pictures Core now does DTS:X and the upcoming Imax certification will also have DTS. I wish users could purchase the codecs to install on their systems if Sonos does not want to pay for all devices.