eARC
No
Dolby Atmos
Yes
Dolby Digital
Yes
Dolby Digital Plus
Yes
DTS
Yes
DTS:X (eARC only)
No
Dolby TrueHD (eARC only)
No
DTS-HD MA (eARC only)
No
5.1 PCM (eARC only)
No
Over HDMI ARC, the bar supports Dolby Digital and DTS for 5.1 surround sound on streaming platforms and Blu-rays. The SK9Y also supports Dolby Atmos and Dolby Digital Plus as a carrier for object-based surround sound. Unfortunately, you won’t be able to play lossless formats via ARC.

https://www.rtings.com/soundbar/reviews/lg/sk9y