garych

You can't, if that's feasible, 2 sounds come out at the same time, what sound do you want to hear?

I have a 12.1" Tesla style screen android unit purchased from dvdgpsnav, it has video output to support rear screen, and my 18 speaker system still works after installation, there's not a fiber optical box outside, maybe it's inside the unit. If you would like to check it, here's the link: https://www.dvdgpsnav.com/blog/toyota-alphard-head-unit-replacement-android-radio-upgrade-navigation-multimedia-system-tesla-style/ any questions you can contact them directly via email or contact me.