A common problem that occurs when you connect your device to a new monitor or into an AV system by HDMI or DisplayPort, is a lack of sound when you try to play a video or audio file. This happens because the computer sometimes thinks the sound should travel to whatever you've plugged into, regardless of it actually possessing speakers. Sometimes due to system settings, the opposite happens and it tries to play out of your built in speakers instead, rather than where you intended it to play. In any case, here's a few things to check and change to fix this issue:


On Any Device

  • Check your cables - It can be pretty easy for some cables to be accidentally disconnected when a computer, laptop or tablet is moved. Check any audio or HDMI/DisplayPort cables you have connected and ensure everything is seated correctly (DisplayPort cables should "lock" into place, HDMI cables will leave a small gap of about 2mm between the plastic and your device and a 3.5mm minijack (sometimes called "headphone cable") will fit flush.


 Windows 7

  • Check your sound isn't muted or the volume is down - Select the sound icon, usually located by the clock in the taskbar. By default this is in the lower right corner of your screen, but may be different depending on if your taskbar is not at the bottom of your screen. The sound icon typically looks like this  or this If you have the latter crossed speaker icon, your sound is muted and can be rectified by either pressing your volume up key (if your device has one) or by left clicking on the icon and in the popup that appears, selecting the larger version if it, below the slider. This should change to resemble a blue speaker, similar to first image above and sound should now play. Please be aware if your computer volume is at 100%, you may need to adjust your speakers beforehand. Similarly, if you have no curved shapes next to the speaker symbol, you will need to increase the volume using the main slider.  It's also worth noting on Windows 7, the icon above the volume bar represents where it is sending the sound to (usually a speaker icon for  Internal/External Speakers, Headphones for items plugged in, or a TV icon for Monitors/TVs via the HDMI or DisplayPort cable. If you feel this icon doesn't match where your sound is meant to output to, move onto the next step.


  • Check you have the right device selected - Right click on the sound icon and select "Playback Devices" from the menu that appears. Inside the Sound window. If you are already playing video or audio, you may see a green bar where the sound is currently being sent to. Right click on the device you think you need and press "Test". Repeat this until you see the green bar appear and hear 6 notes play out of the speakers you wish to output to.  Once this has been found, left click on the option and press "Set as Default" towards the bottom of the window, where it will place a green tick next to your new Default device,  then finally press "OK". 

  • If you don't see the device you need or there is still no sound - the device you have connected may not support sending sound over HDMI or DisplayPort or may not have working speakers. Try using a different cable or contact your device manufacturer for support. If it is a Trust issued PC, laptop or tablet, call the IT Service Desk on 01772 522185 and have the asset number of your device ready. Alternatively, you can email the IT Service Desk from another account at ITServiceDesk@lthtr.nhs.uk and include a contact number if required for identification purposes. If you are using an AV system within the Health Academy Centres, please also contact the Blended Learning Team so we can check the relevant room for issues.




Windows 10

  • Check your sound isn't muted - Select the sound icon, usually located by the clock in the taskbar. By default this is in the lower right corner of your screen, but may be different depending on if your taskbar is not at the bottom of your screen. The sound icon typically looks like this or this .If you have the latter crossed speaker icon, your sound is muted and can be rectified by either pressing your volume up key (if your device has one) or by left clicking on the icon and in the popup that appears, selecting the larger version if it, to the left of the blue slider. This should change to resemble to first image above and sound should now play. Please be aware if your computer volume is at 100%, you may need to adjust your speakers beforehand. if you have no curved shapes next to the speaker symbol, you will need to increase the volume using the blue slider. 

  • Check you have the right device selected - Using the same popup as above, check the title resembles the output you aim to play the sound through. If you are sending audio to an AV system for example through a HDMI cable, you will not want this to be set as Speakers/Headphones. To change between devices, select the small ^ arrow to the right of  the popup and select the appropriate option. You may need to close and reopen any programs that you are playing video or audio from for this to take full effect.
  • If that didn't work or you don't know which device you need - Right click on the sound icon and select "Playback Devices" from the menu that appears. Inside the Sound window. If you are already playing video or audio, you may see a green bar where the sound is currently being sent to. Right click on the device you think you need and press "Test". Repeat this until you see the green bar appear and hear 6 notes play out of the speakers you wish to output to.  Once this has been found, left click on the option and press "Set as Default" towards the bottom of the window, where it will place a green tick next to your new Default device,  then finally press "OK". 

  • If you don't see the device you need or there is still no sound - the device you have connected may not support sending sound over HDMI or DisplayPort or may not have working speakers. Try using a different cable or contact your device manufacturer for support. If it is a Trust issued PC, laptop or tablet, call the IT Service Desk on 01772 522185 and have the asset number of your device ready. Alternatively, you can email the IT Service Desk from another account at ITServiceDesk@lthtr.nhs.uk and include a contact number if required for identification purposes. If you are using an AV system within the Health Academy Centres, please also contact the Blended Learning Team so we can check the relevant room for issues.

Whilst our support does not typically extend to devices external to the Trust, this collection of resources and tips should help with connecting such devices to our AV systems. 

Apple Devices

  • Mac devices should switch automatically on connection of a HDMI, Mini DisplayPort or headphone jack cable to them. If this doesn't happen automatically, follow this guide on OSXDaily and select your relevant correct output in each step.
  • Devices running iOS will typically switch to the last connection plugged in - for example if you plugged in some headphones the sound would be routed to there. If AirPlay was previously used and not disconnected, this can sometimes override any devices plugged in. Both can be changed using Control Centre by following this guide on iMore.

Chromebooks

  • Mac devices should switch automatically on connection of a HDMI cable to them. If this doesn't happen automatically, or the wrong device is selected, follow this guide on HowToGeek to set it to the correct output.

Android Devices

  • Unless Casting or Bluetooth are enabled, Android devices should switch automatically to the last connection plugged in. Depending on the make and model of your tablet/phone you can turn off Bluetooth either in the notifications pane (swipe from top to bottom) or the Settings App. To stop casting, find the app you previously started this on (or use the Google Home app if you have it), select the icon and select "Stop Casting". If you cannot find the relevant app, then a restart of your phone should also break the connection.