If you set up and connected, but no sound from the headphones, please check below step by step.
1. Audio input not valid
Check transmitter audio setting- short press once to choose the right mode on Oasis Plus- OPT for optical and AUX for AUX/RCA.
2. No audio signal into the transmitter
If connected using OPTICAL port, 1) Ensure your TV audio format is set to “PCM”; 2) Change your TV audio OUT setting to “External Speaker”.
If connected using the RCA ports, 1) Make sure you use the Red/White ports labeled “AUDIO OUT.” Other RCA ports will not work. 2) Change your TV audio OUT setting to "External Speakers."
If connected using AUX/3.5mm audio out, change your TV audio OUT setting to "Headset", and try plugging a headphone directly into the TV, see if you can hear anything.
3. Transmitter and headphones are not connected properly
Reboot both the headphones and the transmitter, they should auto connect to each other. Once connected successfully, LED on the headphones will turn SOLID BLUE, and you’ll hear ”Welcome to Avantree. Connected” from the headphones, and “Connected. Ready for use” from the transmitter. The “TX” LED will stop flashing and “A” will light up.