KEF LSX optical input not working

Troubleshooting Guide: KEF LSX Optical Input Not Working

The KEF LSX is a popular and highly regarded wireless speaker system that offers exceptional audio quality. One of its notable features is the optical input, which allows users to connect their devices and enjoy high-fidelity sound. However, encountering issues with the optical input can be frustrating. In this article, we will explore some common reasons why the KEF LSX optical input may not be working and provide troubleshooting steps to help you resolve the problem.

1. Check the Optical Cable and Connections

The first step in troubleshooting any connectivity issue is to examine the physical components involved. Start by inspecting the optical cable connecting the source device to the KEF LSX speakers. Ensure that the cable is securely plugged into both devices and that there are no visible signs of damage or fraying. If the cable appears damaged, replace it with a new one to eliminate it as the source of the problem.

2. Verify Source Device Compatibility

Before assuming there is a problem with the KEF LSX speakers, confirm that your source device is compatible with the optical input. Check the specifications of your source device, such as a TV, game console, or media player, to ensure that it supports audio output via an optical connection. Some devices may require specific settings or configurations to enable optical audio output, so consult the user manual or manufacturer’s website for guidance.

3. Select the Correct Input Source

Ensure that the KEF LSX is set to the correct input source corresponding to the optical input. Most speaker systems, including the LSX, provide multiple input options such as Bluetooth, Wi-Fi, and auxiliary. Use the remote control or the physical buttons on the speaker to cycle through the input sources and select the one labeled “Optical” or “Digital In.” It’s worth double-checking this step as an incorrect input selection could cause no sound output.

4. Reset the KEF LSX

Performing a factory reset can sometimes resolve persistent issues with the KEF LSX speakers. To reset the speakers, follow these steps:

a) Turn off the speakers and disconnect the power cable from the wall outlet.
b) Wait for approximately 30 seconds.
c) Reconnect the power cable and turn on the speakers.
d) Set up the speakers again using the KEF Control app or the manual setup process.

5. Update Firmware and Software

Outdated firmware or software can cause compatibility issues, including problems with the optical input. Visit the KEF website or use the KEF Control app to check for any available firmware updates for your LSX speakers. Follow the instructions provided by KEF to update the firmware. Additionally, ensure that your source device’s software and drivers are up to date, as they can impact the performance of the optical connection.

6. Test with Alternative Source and Cable

To determine if the issue lies with the KEF LSX or the source device, try connecting an alternative device using a different optical cable. This test will help identify whether the problem is specific to a particular source or cable. If the alternative source works properly with the LSX speakers, then the initial source device or cable may be faulty and require further inspection or replacement.

7. Contact KEF Support

If you have exhausted all troubleshooting steps without success, it is recommended to reach out to KEF’s customer support team. They can provide specialized assistance and guide you through additional troubleshooting steps or arrange for repairs if necessary. Provide them with a detailed explanation of the steps you have already taken to help expedite the support process.


The KEF LSX wireless speaker system offers a superb audio experience, and the optical input plays a crucial role in connecting external devices. If you encounter any issues with the optical input, following the troubleshooting steps outlined above can help you identify and resolve the problem. By checking the physical connections, verifying source device compatibility, selecting the correct input source, resetting the LSX, updating firmware and software, and testing with alternative sources and cables, you can increase the chances of restoring the functionality of the optical input.

However, if all else fails, don’t hesitate to reach out to KEF’s customer support team. They have the expertise and knowledge to assist you further. Explain the steps you’ve taken so far, provide any relevant information, and they will guide you through additional troubleshooting or arrange for necessary repairs.

Remember, technical issues can occur with any electronic device, and the KEF LSX is no exception. The key is to remain patient, methodical, and systematic in your approach to troubleshooting. By following the steps outlined in this article, you can increase the likelihood of resolving the optical input issue and continue enjoying the exceptional sound quality that the KEF LSX wireless speakers provide.

In conclusion, experiencing difficulties with the optical input on your KEF LSX speakers can be frustrating, but it’s not an insurmountable problem. By carefully examining the physical connections, verifying compatibility, selecting the correct input source, resetting the speakers, updating firmware and software, and testing with alternative sources and cables, you can troubleshoot and potentially resolve the issue. If you’re unable to fix the problem on your own, don’t hesitate to contact KEF’s customer support for further assistance. With patience and perseverance, you’ll be back to enjoying your audio experience with the KEF LSX speakers in no time.

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