I have connected a Sony soundbar to a toshiba TV via the optical cable and it works fine. However when a select another output I still get the TV audio not the output audio I've selected. I've turned TV volume to zero, doesn't make any difference. Any advice please?
The TV volume control will not work on the optical output which is fixed.
Do you mean that when you select say a DVD player which is connected to the TV as your source you get no sound thru the soundbar from it?
Check the owners manual of the TV to make sure that it will output audio from external sources. You may have to connect an audio out from the other sources directly to the soundbar,
Do you mean that you have a source connected directly to the soundbar and it will not switch to that input? If you have done the set up required in the manual it sounds like there is a problem with the soundbar.