Audio

Audio, music and sounds are reproduced directly by a device's internal speakers, or by connection to an external amplifier and loudspeakers (or Interactive White Board or Sound Field, if available). Audio can also be played indirectly (streamed) without a physical connection using the Airplay feature on Apple TVs

No sound - general

 * Check the sound isn't muted (F10 key on Apple keyboards = mute).
 * Check the sound isn't set to its minimum level (F12 key on Apple keyboards = increase volume).
 * Check the Sound settings in System Preferences. In the Output section there will be a list of available devices, make sure the correct output is selected.

No sound - Promethean interactive white boards with built-in speakers

 * Is the speaker system turned on? The power switch is on the left side of the screen, as are volume and tone controls. The button illuminates green for on, red for off.

Where the computer is connected to an Apple TV via Airplay

 * Check the Sound settings in System Preferences. In the Output section there will be a list of available devices, make sure the correct Apple TV is selected.
 * By default, Airplay should automatically select the same Apple TV unit for both audio and video, but in rare situations you may find you try the above step but the selection keeps returning to the default choice of Internal Speakers. In this case go to the Airport icon on the menu bar and select "Turn Wi-Fi Off", wait a few seconds until the icon turns to a grey outline and then turn it back on again.
 * Ensure the volume control on the Mac is set to a reasonable level and hasn't been muted.

Where the computer is connected via the headphone socket to external speakers or a soundfield

 * Check the audio cable is properly connected to the Mac's headphone socket.
 * Ensure audio cables are firmly engaged when connecting to a soundfield or amplifier, and please report any damage to input sockets to ICT Support promptly.
 * Wall-mounted sockets for soundfields have a small volume control under the input sockets, ensure this is not set to its minimum position.

Where the computer is connected to an Interactive White Board via USB

 * Check the Sound settings in System Preferences. In the Output section there will be a list of available devices, make sure "Promethean USB Audio" (or similar) is selected.
 * When using VLC check you have the correct sound output selected. To do this go to VLC > Audio > Audio Device and select "Promethean USB Audio". VLC occasionally needs restarting if audio stops responding after changing the output selection.

VLC - Distorted / "tinny" sound

 * VLC has its own volume control in addition to the main system volume control. If you are experiencing distorted sound check VLC's volume level isn't set too high, setting the volume slider to around half way generally gives good results.