The Range Rover Sport suffers from poor low frequency (Bass) response.
This is primarily because the subwoofer in the rear door is not as good as the rest of the audio system in the vehicle, and the vehicle needs some Dynamat to reduce echo / vibration and panel flex.
We built a special mounting to sit behind the left hand boot carpet, completely out of sight, with a 10″ JL subwoofer and a small Rockford Fosgate amplifier which we set-up to be superbly matched to the sub-woofer.
We also add Dynamat sound deadening in certain places around the boot area both to perfect the low frequency sound from the new subwoofer and to prevent rattling when the bass levels are turned up.
Here is a picture of the partially installed system. Once complete nothing is visible!