eac3, alsa and some questions

Hi, fisrt i belive i know the answer and is NO. But since i’m not the brightest, i want to ask to be sure. I’m trying to reproduce a file (mkv) with 5.1 eac3 codec audio. My hometheater It is only reproducing left and right channel, so i can’t hear all the dialogues.
I have the following configuration: Ubuntu (with alsa) and kodi 17, i’m using my dedicate video board hdmi to get the sound to my tv where i connect several sound sources and from the tv i use and optical spdf to my home theater. I can reproduce 5.1 ac3 without any problem. Is anything else i can do, for what i read i can’t use spdfi for hd audio. but i don’t know if this applies to my configuration.
Thanks