Make sure that the LVL 6+ headset is securely connected to the AUX port of the device you're using.
Make sure that the volume of the used device or console is set to a suitable level to be able to hear this on the headset, if the volume is too low, then please refer to your consoles or mobile device's settings to turn the volume up.
Make sure that the volume level of the headset itself is properly turned up to ensure that you'll be able to hear the audio from the headset.
Make sure that when you're using the headset in active mode, that the batteries in the headset provide enough power. If there is no audio coming from the headset while in active mode, then change the batteries on the device. (The battery life of the headset is an average of 20 hours, depending on the game, the volume and the brand of batteries that's used with the headset)