Audio Settings when using 5.1 via coaxial cable

Hello everybody,

I am pretty new to the whole kodi world and have some questions. First of all we own two fire tv sticks. On both kodi 17.1 is running. Via kodi I access two external HDDs which are connected to a Fritzbox (NAS).

1. Does anyone have suggestions why the 1st fire tv stick which is older an further away from the fritzbox got a better internet connection than the 2nd one which is newer, nearer and has no walls between fritzbox and itself? The fritzbox tells me the 1st Stick has a 144 mbit/s connection and the 2nd one only sth. about 100 mbit/s.

2. I have a 5.1 Soundsystem (Logitech Z906 https://www.amazon.de/Logitech-3D-Stereo…itech+z906) connect via a coaxial cable (https://www.amazon.de/gp/product/B000O77…UTF8&psc=1) to my tv. As I am not so experienced with sound technic I don’t know how to adjust the settings in kodi. I have made some screenshots what they look like right now (https://goo.gl/photos/EQbKaKUe25UucDwm8). Sometime when I start a Video via kodi, the video is playing properly but i don’t get sound. After stopping and restarting the video it is working mostly. Besides I got the feeling that the Buffering which occures sometime comes from wrong sound settings.

Thank you very much and have a nice weekend. Greetings, Jan