How to Install Subwoofers in a Car

Most car manufacturers do not include subwoofers with the factory stereo system. The process of installing them can be complicated, so avoid hassle by purchasing a prefabricated enclosure box equipped with subwoofers. Make sure you gain proper knowledge as well as tools, so your installation is a success, as an improper installation can cause damage to your vehicle.

Difficulty: Moderate

Instructions

Things You'll Need:

• Four-Channel Amplifier
• Subwoofer box with subs
• Manufacturer Recommended Cabling
• Phillips Screwdrivers
• Car Stereo Wires
• Spray Glues
• Rollers
• Subwoofer Enclosures
• Brackets
• Variable-speed Drills
• Blow Dryers Or Heat Gun
• Car Stereo Subwoofers

1. Reconfigure the speaker hookups on your four-channel amplifier so that the front and rear speakers already in the system are using the 2 front channels of the amplifier. The front channels of the amplifier should have a high-pass crossover to work these speakers.

2. Bridge the rear channels of the amplifier into mono so that the amplifier will supply twice the power. The instructions that came with the amplifier will show you how to do this.

3. Wire the two subwoofers into the amplifier using 12-gauge speaker wire (unless otherwise specified by the instrutions). The rear channel of the amplifier should have a low-pass crossover.

4. Test to see what the best crossover point is for the subwoofers.

5. It is recommended to use metal L-brackets to brace the enclosure. Secure the box to the floor, a wall or the rear deck. Be sure to place silicone around the bracket so that air will not leak from the box. Note: If your spare tire is located in your trunk (which is common on most vehicles), you may want to skip this step.

Tips & Warnings

• Play around with the positioning of the subwoofer box in the trunk to get the sound you want. You may find it best to point the box so that the subwoofers are aimed toward the rear or toward the interior of the vehicle. When pointing toward the rear, the sound wave has a longer distance to travel, and you get more bass as a result. Directing your box towards the seat will add a vibrating more powerful feeling to the interior but can also cause damage to the subwoofer if placed to close to the seat.
• To test for the best crossover point for the subwoofers, set the low-pass crossover of the amplifier at 100 Hz and play something on your system. Watch the movement of the subwoofers. The lower the crossover-point frequency, the less movement on the subwoofers. Watch to see whether the subwoofers are moving too much and listen to the music to determine whether there is distortion. Most systems run at 85 or 80 Hz.
• Make sure you seal the box in it's correct position and use the proper depth screw
• To deal with vibrations, you can spray your trunk with a polyurethane based product, although this can be a bit costly. A cheap alternative is spray foam insulation that one would use around windows and cracks on a house. This can be picked up at your local home center.
• Before you place the L-brackets, check to see what is on the other side of the surface you will be screwing into. You don't want to cut a gas line or wire.

[koloff]

on 12/16/2007 I have heard a lot of rumors about the "proper" way to set subs in a trunk. Should I face the bass ports to the back of the trunk or face them to the seats?

[belcat]

on 1/15/2007 The crossover point is usually determined by playing something. If it's too high, then some of the bass sound ends up being played by both the regular speakers and the subwoofer - so those frequencies sound way too loud compared to the others.

on 8/8/2006 The main thing when you get the sub is where and how you place it. For Bazooka's, point it to a corner and play around with the distance in the corner. You might be surprised with the difference.
If you have a normal sub-place it facing the back of the car. After this find a way to secure it in place (using belts or some high friction clot ( any wool cloth ). Remember the base travels through the boot to the car and then to you. So it's how well you tune it with respect to the car.
Use the sub woofer filter if you have on. For high power subs, around 85Hz is good.

on 8/8/2006 Make sure when you build a box for your sub woofer that you have a tight, well enclosed space behind the magnet. Make sure to use thick wood, like MDF, and seal all edges with silicone. If placing the subs upside down, do the same, but place the front of the sub into the box. Make sure you do the opposite, and leave as little space as possible so the magnet can kick out into the interior.

on 8/8/2006 Most people think that you can only cover the port holes to get more bass. But you can line you box with stuff. I at first thought the eggshell foam stuff would work, but there is no difference, so I loaded it with a whole bunch of cotton and my 2 10's never sounded better.