Free Air Subwoofers (Defined, Common Misconceptions, Uses & Tips)

Free-air subwoofers have gained popularity for their unique design and space-saving benefits. 

However, there often needs to be more clarity surrounding these subwoofers, their uses, and the best practices for their installation. 

In this article, we will clarify the free air subwoofers defined, debunk common misconceptions, explore their various uses, and provide valuable tips for their installation. 

Free Air Subwoofers Defined

What Are Free Air Subwoofers?

Free Air Subwoofers is a sound system mounted directly on the car’s trunk or back shelf. Unlike other speakers, it does not need installation and can produce low-pitched sounds like bass and sub-bass. 

Uses Of Free Air Subwoofers 

There are several advantages to using these types of sound systems; 

1. Flexible Connections

Some models come with wires that allow you to play sounds directly from other sources like smartphones. 

2. Easy Installation 

It doesn’t require installation in an enclosure or a large box. Instead, it can be mounted directly on your car’s rear package shelf or a panel in the trunk.

3. Sound Quality 

It gives the vehicle sound a richer quality by enhancing the performance of the main speakers. 

A subwoofer will take your music-listening experience to the next level, providing a full range of sound so you can truly enjoy all of the sound frequencies in your music, not just high and mid-range notes.

4. To Save Space

Free air subwoofers are designed to be mounted directly onto a rear deck, parcel shelf, or any suitable mounting surface in the vehicle. 

They don’t require a special enclosure, making them a space-saving option for vehicles with limited trunk space or those who prefer to keep their trunk area free for other purposes.

5. Protect The Audio System 

Without a subwoofer, the bass could spoil or damage your audio system, putting the speakers at risk of being blown out.

Other Types Of Air Subwoofers 

Aside from free-air subwoofers, there are other types of subwoofers commonly used:  

1. Ported Subwoofer 

A ported subwoofer is a type of subwoofer that uses a port or vent in its enclosure to enhance bass output. The enclosure is designed with a specific opening called a port, which allows air movement in and out of the subwoofer.

Ported subwoofers are designed to give you more volume and output with less power than sealed ones. They are very efficient, meaning you can get a strong bass response without needing excessive power.

2. Sealed Subwoofer

A sealed subwoofer s a type of box that houses a subwoofer speaker without any openings or vents. 

Unlike ported or bandpass enclosures, a sealed enclosure does not have a specific way for air to escape from the box.

However, compared to other types of enclosures, they are not as efficient, which means you’ll need an additional amplifier to achieve the same volume level as a ported enclosure.

Sealed subwoofers are well-suited for jazz, pop, classic rock, folk, indie, and classical music genres.

The sound produced by a sealed subwoofer can be described as clean, accurate, and balanced. 

It doesn’t have as much booming bass as other enclosure types, but it emphasizes accuracy over loudness. 

3. Bandpass Subwoofer 

A bandpass subwoofer enclosure is a type of box that combines elements of both sealed and ported enclosures. 

It is typically larger, requiring more trunk space. Bandpass enclosures are designed for severe bass enthusiasts who want powerful and booming bass.

The main difference between a bandpass and a ported enclosure is that the port and the rear of the subwoofer driver are in separate enclosures in a bandpass design. 

This configuration allows for specific frequencies to be emphasized, resulting in louder and more impactful bass at those frequencies.

Common Misconceptions of Free Air Subwoofers 

Many people have several myths or misconceptions about free air subwoofers. Here are some of these misconceptions, and let’s see if they are true: 

1. Angling Speakers Toward The Listener Provides The Best Sound

This is only sometimes the case. It depends on the individual speaker design, listener preferences, and the desired sound characteristics. 

There are instances where speakers are intentionally designed to be listened to at an angle rather than facing directly.

Off-axis measurements in reviews can provide valuable insights, allowing you to position the speakers accordingly for the most accurate and pleasing sound experience.

Also, if you prefer a more aggressive sound with greater detail, facing the speakers directly towards you might be the preferred option. 

However, if you prefer a calm and warmer sound, angling the speakers outward and placing the listening position at an off-axis angle could be more suitable. 

There are also cases where speakers are designed with a very aggressive toe-in, causing the tweeters to intersect in front of the listener. 

This is often seen in speakers with narrower dispersion characteristics and is intended for specific listening preferences.

2. Not All Cars Can Fit a Subwoofer

Not all subwoofers are big and bulky, and you don’t need a large trunk to accommodate them. 

Many options exist to add a subwoofer to your car audio system without taking up too much space.

Even if the car is small, audio professionals can find ways to fit a subwoofer without compromising sound quality or occupying too much room. 

You can install a shallow-mounted subwoofer under seats because they don’t occupy much space.

Also, you can install Compact-powered subwoofers with built-in amplifiers, so they don’t need a separate amplifier. They can also fit under a seat.

Another option is to get Small free-air subs. These can be installed in door panels or on a rear deck. In addition, Vehicle-specific subs can blend into your car’s interior and only take up a little space.

3. Music Bass Requires A Superior Subwoofer Compared To Movie Bass 

Advocates of this myth claim that music is recorded or mixed with higher quality than film or television. 

Therefore, audio enthusiasts need a high-fidelity subwoofer specifically for music. In contrast, the performance standards for subwoofers in film/television content are lower.

It is not entirely accurate because Music bass tends to be simpler and cleaner, making it less challenging for subwoofers to reproduce accurately. 

On the other hand, movie sound effects can be more complex and demanding, making the differences between subwoofers more apparent. 

However, a subwoofer that can accurately reproduce movie sound mixes will be okay with handling most recorded music.

4. Subwoofers Must Fill The Entire Room With Bass To Provide Good Sound 

The notion that you need a massive subwoofer system to fill the entire room with loud bass to achieve good sound at the listening position should be dispelled. 

Proper placement and proximity of the subwoofer can deliver a satisfying bass response without excessive power or energy consumption.

5. Installing Acoustic Treatments Anywhere In A Room Will Automatically Improve Sound Quality

Acoustic treatments are not a one-size-fits-all solution. They are designed to address specific sound problems in a room. 

Simply putting up treatments without understanding the issues is unnecessary and may worsen the sound. 

If you want to use acoustic treatments effectively, it’s essential to do your research or consult an acoustician. 

6. One Expensive Subwoofer is Better Than Multiple Cheaper Subwoofers

It’s only sometimes true that a single high-quality subwoofer is better than having multiple cheaper subwoofers. 

The reason is that most subwoofers sound similar when they are operating within their normal range. 

The most significant difference in sound quality is how evenly the bass response is reproduced. 

Achieving a consistent and even bass response relies on having a more balanced activation of the room’s acoustic modes. 

While equalization (EQ) can help by flattening peaks in the response, it has limits, especially when addressing dips in the response.

Using multiple subwoofers can often be a better option. When adequately set up, multiple subs can work together to provide a more even bass response. 

7. Sealed Subwoofers Are Faster, Tighter, And More Accurate Than Ported Ones

The accuracy of a subwoofer is not solely determined by whether it is sealed or ported. It depends on its overall performance.

A well-engineered ported subwoofer performs just as well as a sealed subwoofer regarding timing and human hearing. 

Ports can provide higher output at their tuned frequencies while keeping the driver operating comfortably and reducing distortion. 

On the other hand, sealed subs need the driver to work much harder to achieve the same sound pressure level for lower frequencies, which can lead to more distortion.

8. It Is Impossible to Upgrade Your Car Stereo System

Contrary to what some may think, upgrading your car’s stereo system is possible, even if you have a modern built-in stereo connected to various electronic features like heating, air conditioning, and GPS.

You may not be able to upgrade yourself, so you must hire a Car audio specialist to do it for you.  

Working around your factory radio, they can add new components like amplifiers, subwoofers, and speakers to your existing system. 

They can also enhance your factory system with features like iPod and Bluetooth adapters, satellite radio, or CD changers.

9. Ported Subwoofers Are Best For Home Theaters For Movies And May Not Be As Good For Music

While ported subwoofers are often found in home theater setups, many prefer them in their cars to enjoy music.

They are particularly well-suited for music genres like rock, hip-hop, and any music with a solid and impactful bass presence. 

So, if you enjoy music that bumps and want a powerful bass experience, ported subwoofers can be an excellent choice.

Tips For Free Air Subwoofers 

Installing a free-air subwoofer requires some considerations to ensure optimal sound quality. 

Here are some tips to use:

1. Isolate Sound Waves

While free-air subwoofers are less sensitive to wave interference, better isolation can improve their sound. 

When installing the subwoofer through the rear deck, use materials like Dynamat to absorb and reduce vibrations. Reinforcing the rear deck with a more rigid surface can also enhance the speaker’s response.

2. Use a Baffle Board

A baffle board can improve sound quality when mounting the free air subwoofer to the back of your rear seats. 

A sealed surround helps the speaker sound better. This can address the lack of punchy bass often associated with free-air subwoofers.

3. Consider Alterations

Free air systems may require alterations to your vehicle. If your subs are mounted through the package tray, you may need to make large holes for better performance. 

4. Small Trunk Spaces

Consider a small ported sub-box instead of a free-air subwoofer if your car has a small trunk space. A ported box will provide a significantly better bass response in limited trunk space.


Free-air subwoofers offer a practical solution for adding deep bass to your car audio system without needing large enclosures. 

By understanding their design and addressing common misconceptions, you can appreciate the benefits they bring to your listening experience. 

From enjoying accurate and punchy bass in your favorite music genres to finding innovative installation methods that maximize sound quality, free-air subwoofers open up new possibilities for car audio enthusiasts.


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