One side sound brack

hello, i had the same problem. In my case, the issue was the cable between the left and right speaker being in tension. The solution in my case was to open the headband. first you have to remove the foam part, try to slide a sharp object like a flat screw driver into the seam between the foam part and the frame. Make sure you driver is under the foam part and then drag the screw driver along the seam to loosen the adhesive. Now remove the foam part. you can now loosen the cable to give it more slack. you can now reinsert the foam part. if it still doesn't work, i sadly can't help you.