HDMI Connection Display & Audio Errors on Laptops in Classrooms

Summary

This article provides troubleshooting steps for USNH students, faculty, and staff experiencing audio issues when connecting laptops to classroom AV systems via HDMI. It explains why video may display correctly but audio fails, and outlines a simple reset process to restore sound through the classroom speakers.

 

Environment

  • Classroom AV systems at USNH using HDMI connections
  • Laptops running Windows or macOS
  • Issue may affect students, faculty, or staff
  • Issue may occur when using HDMI cables with or without adapters to connect to classroom displays and speakers

 

Issue

You may encounter a situation where your laptop successfully displays video on the classroom AV system, but no audio is heard through the room speakers.

 

Resolution

To resolve this issue, follow these steps:

Instructions

Step 1 - Disconnect the HDMI cable and any adapter from the laptop.

Step 2- Restart the laptop completely, using the Shutdown or Restart option (not just sleep or hibernate).

Step 3 - Once the laptop has restarted, reconnect the HDMI cable to the laptop.

  • If you are using an adapter, first reconnect the HDMI cable to the adapter and then connect adapter to the computer.

Step 4 - Verify that the correct classroom speaker output is selected.

On Windows

  1. Right-click the sound icon in the taskbar
  2. Select “Playback Devices” or “Sound Settings”
  3. Choose the Classroom AV system (e.g., Crestron Echo Canceling Speakerphone or Crestron (Intel Display Audio)) as the default.

On MacOS

  1. Go to System Settings > Sound > Output
  2. Select the Classroom AV system (e.g., Crestron HDMI)

 

Result

  • Audio is now playing through the classroom speakers when media is played from the laptop.
  • The correct audio output device (e.g., HDMI or AirMedia) is selected in the laptop's sound settings.

 

Workaround

If the above troubleshooting steps do not resolve the issue and audio still does not play through the classroom AV system, Learning Space Technologies (LST) offers a portable speaker loan for classroom use.

These speakers can connect to laptops via:

  • Bluetooth
  • Standard audio headphone jack

To request a portable speaker, contact LST at your campus x2525, press 1, or visit the LST WebCheckout Patron Portal. This solution ensures that instructors can continue their sessions with reliable audio output while further troubleshooting or support is arranged.

 

Cause

This issue typically results from a miscommunication between the laptop’s audio/video drivers and the AV system. When the HDMI connection is established, the laptop may not correctly route audio to the external system, even though video is functioning properly.

 

Need additional help?

Submit a request for Learning Space Technology Support, or visit the Technology Help Desk Support page to locate your local campus contact information or to submit an online technology support request.  For password issues you must call or visit the Help Desk in person.  

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