We were given the challenge by this owner to improve the bass in his Granturismo. The client was very specific about the system being a feature but not over the top. The standard Bose sub-woofer was less than impressive so we replaced it with the Alpine slim 10 inch R-Type sub-woofer. The challenge was that the factory sub-woofer was mounted off-center meaning that the new sub-sub-woofer need to be located through the original hole in the shelf. We found that by placing a larger grille over the rear shelf, we could get a symmetrical look while not having to structurally change the car.
The rear shelf and surrounding panels were sound deadened and the hole in the shelf was built up with a 18mm MDF ring that was fixed to the steel at 12 points for rigidity and clearance of the fuel tank below. The power source for the new sub-woofer as a Rockford Fosgate PBR300X2 that produced a measured 372 Watts RMS (1172 Watts max) for the new sub-woofer and was controlled with a small bass level controller mounted under the steering column for easy access by the driver. Overall, a very impressive result.