300ZX Stealth Box Install

The 300ZX is a sports car made by Japanese automaker Nissan. The vehicle comes standard as a hatchback. Installing a stealth subwoofer box into the car is made easier with this model design as the subwoofer box can be concealed in the trunk of the car if designed to be flat. A stealth box is a subwoofer enclosure that is not noticeable at first glance.

Things You'll Need

• Tape measure
• Table saw
• MDF
• Plexi-glass
• Steel screws
• Jigsaw
• Silicone caulk
• Carpenter's glue
• Speaker wire
• Carpet
• Scissors

Instructions

1. Clean out the trunk and measure its length, width and height. Determine how many subwoofers will be housed in the trunk. The number of subwoofers will change the space requirements of the box.

2. Design the box. This will vary with the type of subwoofers -- whether they're 8 inches or 15 inches. The size of the box will also vary depending on the number of subwoofers. Many installations have two subwoofers, and a stealth box can easily accommodate two woofers while still having space for storage in the trunk.

3. Confirm the measurements for an enclosure with two woofers. The length of the box will be as wide as the narrowest part of the trunk; in the 300ZX this is closest to the back seats. The width of the box will be 4 inches wider than the diameter of the subwoofer. The height of the box will be equal to the height of the rear seats. These measurements should accommodate any size subwoofer.

4. Cut three pieces of medium density fiberboard (MDF). Two pieces should be cut to the length (width of trunk) and height specified in Step 3. The last piece should have the length and width of the measurements in Step 3. These pieces will make up the length of the box; one will be the bottom of the box, and the other two will be the sides.

5. Cut two pieces of MDF for the ends of the box. Use the height and width measurements from Step 3.

6. Cut one piece of plexi-glass to the length and width specified in Step 3. This will be the top of the box.

7. Assemble the box and leave the top plexi-glass part off. Use carpenter's glue to hold the box together. Once the glue is dry, use metal screws to fasten the sides together; use one screw every 6 inches.

8. Cut the subwoofer housing out of MDF. The subwoofers will be angled in the box. They will each be mounted to a piece of MDF; this will accommodate the depth of even larger woofers. The two woofers and their mounts should look like a "V" inside the box when done. Cut two pieces of MDF using the width from Step 3. To determine the length required, measure the distance from the top corner of the box to the bottom center of the box at a diagonal. Cut two pieces of MDF to those specifications.

9. Drill a hole for the subwoofer in the MDF housing created in Step 8. Do this for both pieces of MDF. The hole should be in the exact middle of the MDF. Mount the subwoofers after this is done. Use screws to secure the woofer.

10. Sand the edges on the lengths of the MDF housing created in Step 8. They should be sanded down so that they fit perfectly into the box at an angle. The two MDF boards should meet in the bottom middle of the box with the other end of the MDF at their top respective ends of the box; this should result in a "V" formation inside the box.

11. Drill two small holes at the ends of each box. Run speaker wire through each hole and connect it to the subwoofer's power terminals. Install the subwoofers with their MDF mounts into the box. Use carpenter's glue to secure the MDF mounts into position in the box. Once the glue is dry, screw the MDF mounts into the box.

12. Position the plexi-glass on top of the box and use carpenter's glue to seal it in place. Once the glue has dried, screw it in. Use silicone caulk to seal all the edges of the box.

13. Wrap the entire box in carpet. Ideally, the carpet should match the color and texture of the carpet in the trunk to help the box blend in to the interior better. Use carpenter's glue to adhere the carpet to the box. Once this is done, the box should simply be a carpeted rectangle.

14. Insert the box into the trunk of your 300ZX as close to the seats as possible. Connect the two speaker wires to an amplifier and test out the system.

References

• Audio Gear Reviews: Bandpass Enclosures -- The Magic Box?
• Crutchfield: How to Build a Subwoofer Box
• Car Audio Help: Building Subwoofer Boxes
• DIY Subwoofers: The Subwoofer DIY Page
• "Nissan 300ZX, 1984-1989"; John H. Haynes; 1986