If you are using mumble for a show and you would like to set up a listening room, where listeners can listen to your show, talk amongst themselves but not interfere with the show itself, here is one way to set it up.
Right click on the root channel, click add and create your main channel, which we’ll call it ‘Pointless’ for this example.
Right click on the Pointless channel, click add to create a subchannel, which we’ll call ‘People With No Lives’.
Enter Pointless and right click on People With No Lives and click ‘Link’. This allows users in both channels to hear and talk to each other across the channels.
Next, right click on Pointless and choose ‘Edit’. Click on the ‘ACL’ tab. Click ‘Add’, untick ‘Applies to sub-channels’, but make sure ‘Applies to this channel’ is selected. Under the ‘Group’ pulldown, choose ‘out’. In the ‘Speak’ row, tick the box in the ‘Deny’ column. This prevents users in other channels from speaking into the channel you are editing the rule for.
This will leave you with your main channel, Pointless, a subchannel, People With No Lives. People With No Lives can hear Pointless and talk amongst themselves, but Pointless will not hear the chatter from People With No Lives.
If you do not want people within the subchannel to be able to speak with one another, add an ACL to the subchannel, group ‘in’, toggle deny speak. I should note here that trying to deny speak from the main channel while applying it to subchannels seems to completely supress anyone in the subchannel. They can neither speak nor hear the linked audio.
I’m sure there are a half dozen permutations of these rules which will do similar things. If your show’s cast is stable enough that dealing with group registrations is a viable option, you are probably better off going that route.