Building the Subwoofer

The driver for the bass would be a 12" Legacy LWF12 Subwoofer.
This was chosen because of its competitive pricing and its styling. (The foam surround matches the colour of the bass amp)
I had several choices of box design available to me: - Sealed, Ported or Bandpass.
Sealed boxes tend to sound clean but need a healthy dose of amp power because of their limited efficiency; I don't really like the sound of Bandpass boxes (I consider they sound too aggressive for dance music) so I chose a ported box. The design program I used prompted me to build a 1.81cu ft box, with a 4”x6.03” port.  A good ported design should also give around a 3 dB gain over a sealed design.

 Firstly, I used a program called 'Loudspeaker 30' to obtain the correct box design.
Download 'Loudspeaker30.exe'

This was what it came up with: -

Legacy 12" LWF
1.81cu ft enclosure
4" round port, 6.03" long
Tuned to 45 Hz

The sub enclosure was built of 18 mm MDF, to the aforementioned size.  Allowances
were made for speaker and port volume displacement.  The port was made from a
piece of plastic pipe I 'liberated' from a shops bin!  Silicone bathroom sealant was
applied to the edges of the joints inside the box - this ensured that there were no
performance reducing air leaks.

That's the basic box, the port has been primed ready for spraying.
The silicone sealer is also visible inside the enclosure.

Once the box was finished, it needed to be integrated into the car.
I wanted to be a little original in my approach here, as the subwoofer is probably the
main focal point of the install.

This is what I came up with.  I attached another piece of MDF to the front of the
box (which had been cut to fit around the wheel arches).

This gives a good view of the whole idea...

This is the finished subwoofer build.  The still visible parts of the wheel arch were
also covered with black carpet, as was the underside of the parcel shelf.
The port was sprayed a pearlesant purple to match the bass amp and the speaker surround.