I've recently replaced the standard dual cone subwoofer with a more "modern" compact subwoofer.
Reasoning was twofold. Firstly I wanted the packing space being taken up by the standard sub and secondly the standard units speakers were torn anyway, so it was just taking up space and not contributing anyway.
I decided to go for a Phillips unit. It is nice and compact and seemed to get some good reviews. It's power requirements also fell within the cars limits, so no need to change out fuses or uprate wiring to supply the sub.
The new subwoofer fits nicely inside the space between the outer skin of the vehicle above and just behind the left rear wheel arch. This means that the full space previously occupied by the standard sub is now available for packing more beer. Perfect.
I first set about fabricating a mounting bracket for the sub that wraps around the back of the sub tying into the standard mounting holes of the sub:
The idea was to support weight of the sub from the top and bottom with a tight fitting bracket. The sub is supplied with some self tapping fasteners that screw into the sub itself, but I needed the fasteners to be flatter so I used some countersunk M6 fasteners. I tapped the holes in the back of the sub to M6 which worked nicely.
To mount the sub to the car I enlarged two of the standard cable handling clip holes above the proposed mounting location and fitted two rivnuts. Now I had nice threaded holes for the top of the sub mounting bracket to attach to:
For the bottom mounting I welded a nut to the sub mounting bracket (which can be seen in the 2nd image above) and drilled a hole in the body for another fastener to screw into the sub mounting bracket:
The wiring was very simple with the sub only needing a Battery Supply, an Ignition Signal (from the radio to make the unit power up), a Ground Return and an Audio Signal (so 4 wires). These happen to be exactly what the standard subwoofer uses, so I just cut off the standard connector, fitted a DT connector that I had lying around to the vehicle wiring and the sub wiring and tested the unit. Worked well.
The electrical connector I cabletied to the top of the sub mounting bracket like so:
As can be seen from the images above I also stuck some sound insulating/damping material to all the body panels in the area. Without this insulation all the vibrating body panels absorbed the energy making the sub not sound great and diminishing its power quite a bit.
The standard rear wing inner "cover", or whatever it is called, is filled with gaping holes for the mounting hardware and wiring of the standard sub to move through and attach. These holes now needed to be covered up.
I decided to 3d print covers for these holes, in thin semi flexible material so that it could bend and conform to the shape of the wheelarch lines cover thingy. I heated these up, shaped them as required and then fitted them. I didn't take any pictures of this part, but I'll post some picture later. It worked quite well, and I even printed a mount for the subwoofer remote, with a clip in cover, that fits inside one of the gaping holes. Some of the clips holding the covers in place broke off during fitment (layer line breaks) but all in all the covers worked well and look decently good for what they are. Pics of this to follow.