One Side Sound/Louder. What to do?

Is there any AUX / RCA cable on the audio stream passway? For example, the 3.5mm cable between your TV & the transmitter. If yes, the most often cause of One Side Sound is that this cable is defective. Please try with another audio cable and see.

If a replacement audio cable fixes the issue, please contact Avantree Support for the replacement cable.

If not, the next step is to test the audio device with your cellphone Bluetooth DIRECTLY.  

If it is still one side sound only under Bluetooth mode with your cellphone, then please try the following: 

1. Plug and unplug the 3.5mm audio jack into the headphone port twice and see if the problem is fixed.

2. Please factory reset the Bluetooth headphones (Find the guide under its product support > Guide & Troubleshooting >  Basic & Advanced Features > Factory Reset the device)

For the earbuds (NB16), we found that a large proportion of one side sound or one side louder issue was caused by earwax blocking the eartips.

In this case,TAKE OFF the eartips and CLEAN the earbuds by this instruction - How to Properly Clean the Earbuds. Also make it a habit to clean your earbuds on a regular basis.

NOTE: If the earwas sticks on the speaker mesh and hard to remove, please contact support@avantree.com for a new pair of speaker meshes to install by this video instruction.

If the problem persists after all the troubleshooting above, please fill the RMA verification Form for One side sound for replacement - https://avantree.com/rma-verification/headphone-one-side-sound-form