Kodi 14 – 5.1 sound via HDMI (issues)

A few months ago, I purchased my first 5.1 surround audio system, an RCA component receiver with 5 surround speakers + subwoofer.

I am running Kodi 14.1 on Linux Mint. I have HDMI out from my NVIDIA GPU connected to the HDMI input on my Samsung 47″ Smart TV. I then have a digital optical audio cable connected from the audio out port on my TV to the digital optical audio input port on my RCA receiver.

Although I do get some semblance of surround sound, I have been somewhat disappointed with the quality. The best way I can describe the glitchiness of the audio is that, for example, if there is background music playing on the FL and FR speakers and dialog/voices on the center speaker, the music on the left and right speakers will stutter and cut out while someone is talking, and then go back to uninterrupted full volume during times when the center speaker is relatively silent. I experience the same thing with sounds coming from the rear surround speakers as well — the sound cuts out when there are loud sounds from the center speaker, and then comes back to full volume when the center speaker is relatively quiet. This same thing happens whether the 5.1 audio is DTS or DD.

I had just been assuming that this was the best quality surround sound that my new system was able to produce, and that I would just have to accept it. But then, I decided to hook up and try the free Google Chromecast that I had received, with a free trial subscription to HBO NOW. The audio signal still originated via HDMI, but it was the HDMI output from the Chromecast, and I watched the season finale of Westworld that way. I was absolutely blown away at how much better the sound quality was. The surround sound was perfect, the way I had always hoped it would be, nice, clear audio from all speakers at all times, with none of the “stuttering” and “cutting out” that I always experience with my HTPC with Kodi.

Does anyone have any suggestions about what I could do to troubleshoot this issue? Has anyone else had a similar problem and found a solution? It’s so hard to go back to watching TV and movies on Kodi with the glitchy audio, now that I know how much better it can be on the Chromecast.

Thanks!