The Beam only has one connection: HDMI (de facto an “in”, there’s no “out”). You can connect optical to the Beam with the supplied adaptor, so still using the HDMI on the Beam. For HDMI the sound has to be provided by an HDMI-ARC connection that is absent on the Sky and the PS4.
The best way to connect the Beam is as follows:
- Sky and PS4 to TV via HDMI;
- TV HDMI-ARC to Beam.
All sound settings (PS4, Sky and TV) should be set to Dolby Digital (not DD+) if possible.
If your TV does not have HDMI-ARC, you can work with optical, again from the TV to the (adaptor to) the Beam. Both PS4 and Sky would be connected to the TV by HDMI.
In both cases (using HDMI-ARC or optical) it is totally dependent on your TV if you get any sound at all (some TV’s do not pass through sound from HDMI to optical) or if you would get surround - though if you only get the Beam the chance there would be no surround would not be of any consequence for you.
If the above route via optical does not work either you would have to work via optical switches.