Xubuntu - Sound Manager

Output Devices - Set Active Speakers

Using the Output Dvices tab, you set the active device for playing sound by clicking on the green tick as shown in the picture below.

The one being pointed to looks like it is indented, marking it as the active speakers.

For some reason if you hover over it, the tooltip says "set as fallback" which is misleading to me. It is not to set a fallback device when your primary one goes away, and only one of your devices can be selected at any one time.

Output Devices - Adjust Different Speaker Levels

If you press the padlock button (1), it toggles the locking of the channels. These are the audio channels for just that device, and is not for locking the various devices together on volume level. By unticking this, you can increase/decrease one of the channels relative to the others by dragging the sliders (2). This is particularly useful when setting up a surround sound system, and some of the speakers might be slightly muffled because they are behind a sofa etc.

Configuration Tab - Disable/Enable Devices

If you go to the Configuration tab, you can see all of your devices. As shown below. This is particularly useful, as its an easy route to disabling your unwanted devices, so that applications don't switch to them.

To disable a device, click on the dropdown and select Off.