To make audio adjustments to the room's various components, select "Audio Only" from the Control Panel "Home" screen. You will see the following screen (you will also find many of the same controls on the "Audio Mixer" screen that will appear after selecting the built-in, laptop, or Blu-Ray / DVD player from the "Home" screen):

Adjust the audio for whichever device you want to change:

MASTER: Controls the overall audio for everything. Note that this can be adjusted using the knob below the display as well, but it will lag a few seconds.

Computers / Blu-Ray / DVD: Control the audio for an external laptop or the Blu-Ray/DVD player.

Podium Mic: Controls the microphone on the podium. This is muted by default.

Microphone 1: Controls the handheld microphone labeled with a "1".

Microphone 2: Controls the handheld microphone labeled with a "2".

Microphone 3: Controls the clip-on lapel microphone labeled with a "3". 

Microphone 4: Controls the clip-on lapel microphone labeled with a "4".

Aux: Controls any speaker that’s plugged into the aux cord located below the drawer on the side. Normally, there’s nothing plugged into here, so you will not need to adjust this setting.

To the right of each of these volume controls select “Mute” to mute any device. It will take a second for the button to register and the button will turn orange when it’s muted. To mute everything all at once, select the mute button to the right of “MASTER” at the top of the display.