As we've said before, bass is one of the best single additions you can make to improve the performance and enjoyment level of your sound system. We wanted bass in our Project Toyota Avalon but not just regular bass. We decided to add big bass, so a 15" Alpine Type R subwoofer was the perfect choice. This is a big subwoofer and it is usually installed in a big enclosure that takes up a lot of trunk space. The challenge was to shoehorn this monster in the corner of the trunk, maintaining trunk space and easy access to the spare tire. This meant using an unusual enclosure building technique, maximizing the use of available space. This month, we'll show you how to build the enclosure base panel, and next month we will finish it up. Send questions to techpanel@sourceinterlink.com with Tricks of the Trade in the subject line, and check out stevebrownuniversity.com.
The Toyota Avalon trunk is large, with a deep well on the driver's side that is perfect for a subwoofer enclosure. A sub mounted in this location loads very well with the vehicle's interior, creating the deepest, loudest bass from a small sealed enclosure | 
With the trunk carpet panels removed, we can see that the trunk has a very irregular shape. In addition, the trunk lid hinges extend down into this area when the trunk is closed. This makes it very difficult to build a fiberglass shell that fits the area while still being removable. | 
A good option in these situations is to use the factory trunk carpet to create the base for the enclosure. First, support the carpet panel evenly, done here with two trash cans. |
Fiberglass resin is applied to the trunk carpet to harden it, creating a good start for our fiberglass enclosure. Be sure to completely saturate the carpet until it is shiny. | 
After applying two quarts of fiberglass resin, let the panel dry overnight. The panel will become very soft until the resin is cured, so be sure that it is supported evenly to avoid warping the piece. | 
With the resin cured, the panel is stiff and fairly strong. Test-fit the hardened panel to be sure it fits correctly in the trunk. |
The resin-soaked carpet is not strong enough by itself, so additional fiberglass resin and mat must be applied. Grind down the rough surface of the carpet with a 24-grit grinding disc so that the fiberglass will adhere better to the surface. | 
The panel is placed back in the trunk so that it can be fiberglassed in position. This technique reduces the chance for warping and also lets us better fit the panel to the trunk with additional fiberglass. | 
Masking tape is placed on the trunk edges where additional fiberglass will be applied. The tape will provide a barrier between the trunk and the fiberglass so that the panel can be removed easily. |