This is my last resort and the first forum I have posted to, as I highly respect the knowledge of this community. I have spent hours upon hours over the past few weeks to resolve this issue, including hours of official tech support from both Apple and Microsoft via phone and remote access, to no avail. I am unable to play music in true 5.1, only 2.1 over HDMI using any media player. This is only a recent issue, I have previously had my music library outputting through iTunes (version 188.8.131.52) in 'true' 5.1 (where applicable). Which is what makes this so infuriating for me I hear all the correct tones from each channel when testing the speaker setup via the Windows sound output configuration wizard, using the HDMI (Nvidia high definition Audio) device. This includes 24bit @ 192kHz. Videos such as TV shows, movies and a DTS object emulator .mkv (available at thedigitaltheater.com) using VLC also output in true 5.1 audio. Configuration: 55" Samsung UE55KU6470 2017 UHD Smart TV - ARC enabled (Optical & HDMI 2.0) Yamaha RX-V673 - 4k pass-through (no HDCP 2.2 support unfortunately) PC - Zotac Nvidia GTX 970 (HDMI 2.0 5.1 PCM supported) PC - Asus Maximus Hero VIII (Optical) Intel i7 6700k 4GHz, 16GB DDR4 OS - Windows 10 64bit Pro (version 1709, build 16299.125) - Samsung 960 Evo M.2 SSD 5.1 - Kef iQ70s, iQ30s, iQ60c & Rel T3 Attempted Fixes: Yes, I have tried updating all of my drivers & firmware! Including Realtek, Nvidia, iTunes, Samsung, Yamaha and even a clean install of Windows 10, performed by the Microsoft support via remote access. Using different media players, iTunes (preferably but I am open to good media library alternatives, I have 200GB+ music), Windows Media Player, Groove and VLC. Before the clean install of Windows, we tried a system restore, but there was no previous restore point. I believe everything in the chain is compliant to handshake the PCM audio for the true 5.1 (especially as it works with videos) Thank you in advance if anyone can help me with this issue!