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How to Stop Car Subwoofer From Moving in the Trunk?

If you have a car subwoofer, you know that it can make a lot of noise and a lot of vibrations, and most car drivers are not aware of how much their subwoofer moves when they drive.

If this happens often, it could cause damage to the vehicle or distract you from your safety while on the road. But, how can you stop a car subwoofer from moving in the trunk? Let’s find out.

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In general, you can solve the problem with a moving subwoofer by installing a sound dampening mat in the trunk. Another and cheaper way is to install the sub using screw-on clamps or straps used for heavy boxes.

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Tip: I am not a fan of having loose items that are moving around the car, and that includes the subwoofer.

To prevent any movements of the enclosure, I use straps that, after bolting to the trunk floor, make a solid base for even the heavy enclosure.

In the article below I will provide detailed information on stopping car subwoofer from moving and advice on what materials you should use.

How Do I Mount a Subwoofer in My Trunk?

The first thing to do is clean up the trunk space before placing a subwoofer inside. The last thing you need is to damage the bass speakers after being hit by a heavy object while breaking.

If the trunk floor is not flat, you have to strengthen it. The best way is to place a floor mat of the exact trunk floor size on the wood and cut it to the needed shape.

This way, you will separate the spare wheel area from the subwoofer space and make a stable floor base for the heavy enclosure.

If you do not have much of a room in the trunk, you can place an amplifier on the top or sidewall of the subwoofer, but it has to be bolted down to make sure it does not move.

Problems Caused by Car Subwoofers Moving in the Trunk

The subwoofer may change its position when the car is running over bumps at high speed or even while breaking. In all cases, it’s not good for your car’s sound system.

  • A subwoofer that changes its position in the trunk may not only reduce sound performance but can be damaged.

I am sure you do not want to replace the bass speaker with a cracked cone, only because its cone hit something in the trunk while the box fell over.

  • Also, if a car subwoofer moves, some parts of the car subwoofer may scratch the car interior, other car audio elements, or wires.
  • A subwoofer moving inside the trunk can also damage the wire connections and cause potentially severe damage to the electrical system in the case of a short circuit, or even a fire.

How Do You Secure a Sub Box In a Trunk?

The simplest way is to place on a trunk floor a special mat that will prevent side movements of a heavy enclosure.

These mats, which you can get at any automotive store, are basically carpet with a rubber backing.

You place it in your trunk and drive away! Now your subwoofer has a stable surface to rest on, and the chances of it moving around while vibrating goes down significantly.

Mats are not great only to prevent moving. They also work as a cushion between the subwoofer and the trunk floor, which helps to reduce rattling and vibrations in the car.

An additional option to secure a sub in the car is to use special nylon straps and place the subwoofer close to the back seat or sidewall in the trunk.

Remember however that the box may take up some space in the trunk, so have an accurate measurement of where you will place the enclosure before making your purchase.

Oh, and remember, do not put anything heavy on top of the subwoofer. Heavy loose objects on top of the enclosure do not work at all, and worse, they can damage the speaker’s cone.

Can I Use My Trunk as a Sub Box?

Speakers to play sounds of excellent quality have to be installed in the boxes.

There are, however, some subwoofers, known as free air subwoofers, that can be installed in cars without enclosures.

For these woofers, the whole trunk acts like an enclosure. Free air subs can be installed either in the rear decks or bolted to the backseats.

The benefit of this type of installation is that you can install car subwoofers even in cars with small trunks, where you don’t have to suffer from a lack of space and still utilize the trunk as a luggage area.

The only drawback is that free air subwoofers cannot produce as much bass as the woofers in sealed enclosures because the open space cancels some frequencies.

Free car subwoofers need to be installed on the solid platform to be able to create sound waves. In other words, you should strengthen the rear deck using either MDF or plywood rather than bolting the woofer to a thin plastic interior panel.

The same goes for subs installed behind the rear seats. They also should not be installed directly to the seats but instead on the added wooden panels.

Which Way Should I Face My Subwoofer in My Trunk?

There are different opinions about which way to face a subwoofer against the car.

The way I and many others recommend is to turn the subwoofer, so it is facing the back of the car. This way, sound waves are directed to one place instead of scattered around the car’s interior.

It may be difficult to do it if the trunk is not high enough, for example, in small roadsters. If your trunk is like that, place the enclosure with the speaker facing the top.

This way, the car subwoofer will not “see” any obstacles around it, and the sound waves will be directed toward the rear window.

Be careful, however, and do not place anything directly on the cone. Otherwise, it can be damaged.

A good practice is to cover the subwoofer with a plastic grill to prevent mechanical damage to the speaker.


To ensure that the car subwoofer stays in its place, it is essential to make it stable in the trunk.

This way, you will prevent it from getting damaged and avoid any unpleasant occurrences during driving. It is also good to know that installing car subwoofers requires attention and patience.

You should take special care of wires and always remember about their solid connection to avoid short circuits after their accidental disconnection.