For many years, race car builders have sought the best way to reduce the weight of their cars. When the modern day racers hit the streets with their lightweight imports, reducing weight seemed like more of a challenge, especially when wanting to add a banging sound system. Many options came to mind, but in one way or another, medium density fiberboard (MDF) found its way into the mix and added those dreaded pounds back on.
It was starting to seem like it would require some extraterrestrial wonder material to get the good-sounding lightweight enclosure that was dreamed of. The answer was close to that. Zero Gravity uses aerospace technologies to create a composite material that's not only lightweight, but also has the sound characteristics of a well-built sound studio.
The composite material combines the clean sweet characteristics of German birch and the wave canceling effects of a 200-lb. test aerospace foam. The total weight of a full sheet of this special produced composite board is equivalent to a box of french fries. Okay, well not that light, but in this we did find that the 11/48-inch acrylic mirror used on the inside of the enclosure outweighed the composite material by three or four times.
Another plus worth mentioning is that the back wave cancellation seemed to produce a deep solid sound equivalent to about double the potential or equivalent to that of a two-sub enclosure. While the assembly and production of these enclosures is more involved than a standard MDF enclosure, the end result is well worth it.
The little tricks to this custom box will include a camera mounted inside to view the subwoofer in movement. To achieve this, acrylic mirrors will line the inside of the box along with strip LEDs to light the way. From there, House of Kustoms custom body and paint in Temecula, California, will be painting the trunk to match the elements of the interior and exterior of this convertible Cadillac. So let's follow along as Zero Gravity and 909 Luxury Wheels share their super-secret technology.
The special aerospace foam is sandwiched between two pieces of German birch creating a total width of 1 inch. | 
The intention for this vehicle was to keep it simple but effective, which called for a serious lineup of Hertz, Audison and a custom twist with a Sony monitor. |
The trunk was first measured out and the general layout for our simple system was devised. | 
The foam is removed with the clean sharp edge of a metal putty knife. Then excess foam and adhesive are removed with fine sandpaper on a flat sanding block of 0.75-inch MDF |
The composite is so light that a single person can safely handle it and guide it on a table saw. | 
The side panels fit like a glove in the grooves that were cut out. |
Using this custom-made guide, the pieces are scored through the first layer of birch and the foam. The pieces are cut just enough to join the corners of the box. | 
The edges are then butted up and checked before proceeding to the gluing stage. |
The same care is given to the hole for the subwoofer. The outer hole is cut to the foam, while the inner hole is cut through. The same steps are taken to remove and clean the excess foam. Note that the inner hole was left slightly undersized to allow a ridge for the excess glue to run off on. This edge will trimmed off later. A 0.5-inch ring of German birch will be set into place using expanding glue. The German birch was chosen for its dense yet lightweight properties. Not to mention it's less likely to split than traditional MDF | 
The amp board is cut and centered in preparation for the cut through. |
The amp panel board is test fit around the amplifier before the amplifier mounts are completed. | 
After the glue has been applied to the edges, masking tape and weight are added to hold it in place. |