If you can't hear anything when using the headphones with your PC, try using a different 3.5mm AUX cable to connect to the PC. If your other cable fixes the issue, please contact Avantalk Support and we'll provide a replacement cable.
If you are using the extension coil cord or one of the adapters, it’s possible that it’s not properly connected. Double check your connection and make sure that it is fully connected. You may need to press it hard to connect. See pictured:
If you are using the headphones with your TV, unplug & plug back in your connecting cable from your TV. This will make some TVs recalibrate its signal, and often solves the issue. Another thing: please check and see if there is something plugged into the HDMI ARC port on your TV. For most TVs, when something is plugged into the ARC port, its other audio output ports will automatically be muted. Please switch to another HDMI port.
Additionally, you can try using the included “Mic to audio adapter for TV” to connect to your TV. Attach the adapter onto the cable, and then insert it into your TV. This may solve your issue.
If you are using the headphones with your AVR that's using ARC, please consider switching to Digital Optical instead.