There where builds for openelec that supported dual audio. So you can select in kodi the analog and the hdmi at the same time. There is a thread on kodi.tv forum about this at this url:
[Project] Dual Audio Output support (Krypton/Jarvis/Isengard/Helix/Gotham/Frodo)
This option is keeping me on the openelec build but i like to go to libreelec.