Hi can anybody help me? I have an s3 8l with Bose and one of the two drivers had started flapping on the sub box. So I bought a second hand Bose sub unit exactly the same of the bay, after installing this I tested it and found that I could see the twoo woofers moving but there is barely any bass at all in comparison to the previous unit even though they are exactly the same? So frustrating! Any ideas much appreciated.