Today I found a razer leviathan v2 pro in some thrift market, the guy was asking $80 for it since he have no idea what brand is it, I tried contacting via Bluetooth to my phone and it worked fine but the sub was very weak, I have a small Vizio soundbar without sub connecting to my pc that has a stronger bass than this whole system, any idea if it's a bug or a hardware problem? Also while looking at the back of the sub I found this short grayish cable that I have no idea what is it for, should I go back and grab it? Is it worth it?