On our server we recently had the problem that we wanted to listen to our high bandwidth Mumble-Ruby-Pluginbot musicbots while talking to some users who used a mobile connection with very limited traffic.
The „local mute“ function does not help here because you get the bandwidth anyway and just do not hear it. And even if you have enough traffic you can’t local mute a user on „Mumble for iOS“.
You can solve this problem with linked channels and some ACL magic.
First you need to add a group named „bots“ and add all music bots on your server to that group. Then create a subchannel named „Low BW“ within your current channel.
Link the new channel with its parent channel and then edit the ACL of „Low BW“ like in the screenshot to deny the permission to speak:
How it works
Users in the „Low BW“ channel can hear all users from the parent channel „Orangenes Zimmer“ but NOT the bots. Users in „Orangenes Zimmer“ can hear all users from „Low BW“.
Several other ACL tutorials (German but with English permission names) can be found here.