Using a free air subwoofer is great for applications where trunk space is at a minimum. It’s usually the easiest and least expensive way to add some bass to your ride without giving up your precious trunk space for a giant subwoofer enclosure.
Since free air subs don’t have an enclosure, they will not take up as much room in your vehicle and can be mounted (in some applications) where they may not even be seen as at all.
In a free-air application, a subwoofer is mounted either in the rear deck or attached to a medium to high density fiberboard placed between the backseats of a car and the trunk. This board makes an airtight seal and turns the entire trunk into an enclosure (which is also known as Infinite Baffle).
Not having to build an enclosure/box for your subwoofer is an advantage. However, since free air subwoofers use the whole trunk as a box, the trunk has to be as sealed as possible from the cabin so that the sound waves from the rear of the speaker cannot reach the front of the speaker to cause cancellation. Thereby, your vehicle might require a new rear deck panel and/or vent to be constructed to accomodate these woofers.[alert-note]P.S : These custom vents and panels could cost as much as a prefabricated or custom box.[/alert-note]
Free air applications require a woofer with a beefier suspension for high power handling and one with better cone damping. This set-up will be relatively less efficient at accurately reproducing the lowest frequencies. Further, more amplifier power will be required as compared to a regular sealed or ported box, but then again, you still have a full trunk.
All in all, a free air setup is a a great solution for you if you want to add punch and presence to your music without sacrificing the entire cargo area on your vehicle.
Free Air Vs. Infinite Baffle
“Is Infinite Baffle and Free-Air the same thing” is a common question that we frequently get asked. The answer is that they are not actually the same thing but are very much related.
In a nutshell, a free air sub is a speaker designed to sound well without the use of an enclosure. It’s built to be mounted in the rear deck of a car, for example, and still sound good.
Infinite baffle on the other hand can be as simple as a board or mounting surface (called a “baffle”). This can be a flat MDF board with your free air sub(s) mounted to it and then attached to back of the seat of a sedan. Many vehicles out there have at least one subwoofer mounted in the rear package tray infinite baffle right next to the full range speakers.
With this type of mounting, the car trunk is typically used as an “enclosure”. However, It must be noted that when mounting your subwoofers in an infinite baffle configuration, you must have a woofer that is capable of operating in an infinite baffle. Additionally, you need to make sure that you seal the mounting baffle as good as possible to prevent the rear waves of the speaker (generated from the back of the subwoofer cone) from cancelling out the front ones.
An ideal infinite baffle mounting can be a serious challenge due to the potential difficulty of sealing off the front and rear of the baffle. Bear in mind that bass (low frequencies) can easily travel through anything that is not solid enough such as the rear seat foam/leather. Any areas not sealed enough between the front and rear of the baffle will decrease the amount of bass
Because free air subs aren’t meant to be mounted in a box, there’s is nothing but the suspension of the woofer to control cone movement. That’s the reason why it’s highly recommended that you opt for an amplifier which has a subsonic filter to filter out and attenuate frequencies so low that your subwoofer cannot reproduce.
Furthermore, Infinite baffle mounting does limit the total output of the woofer and its power handling. That is why it is best to use a woofer specifically designed for this type of mounting configuration.
Infinite Baffle : Pros & Cons
- The infinite baffle system is very simple and easy to install
- Simplified installation on a baffle board ( no full enclosure )
- Smooth frequency response
- Does not take up much room in trunk
- Uses speakers’ natural frequency roll-off
- Separating back waves from front waves is challenging
- Limited power handling
- Limited output
- Requires an amplifier with subsonic filter (mandatory)
- The trunk must be sealed from the cabin to prevent bass cancellation
- Rear side of the driver is exposed along with the wiring and it may not be a clean looking installation
Infinite Baffle/Free Air Application Types
There are various ways to mount your subwoofer the infinite baffle way. All of these follow the same concept. Which of them to use is dictated by your vehicle type. Any of these could work just fine in a a large sedan. However, some of these configurations might not work well in hatchbacks.
Typical Rear Deck Installation
If you have a large sedan, then you’re in luck because you’ll have enough surface area to accommodate a pair of 12 or 15 inch woofers.
These vehicles are the easiest to incorporate an infinite baffle set-up into. However, like with any free-air application, the trunk has to be as sealed as possible from the cabin.
This can accomplished by putting a thick medium to high density fiberboard under the deck and behind the seat.
Back Seat Installation
As shown in the diagram, mounting your free air subwoofer behind the back seats instead of under the rear deck is another type of infinite Baffle.
This is often much easier and less expensive than cutting the rear deck and will not require a ton of modifications to the existing deck panel
Small Deck Installation
The lack of the surface area needed to mount a large free air woofer in the rear deck is one of the most challenging things with many modern vehicles. However, you don’t have to feel left out if this is the case with your car because it is still possible to use free air woofers by venting them through the rear deck as shown in the the diagram.
Sealing the trunk area from the cabin is still critical to a successful installation.[alert-note]P.S : Try to keep the inside dimensions of the front and rear walls of the vent at least four inches apart when working around trunk springs and other obstacles.[/alert-note]
Best Free Air Subwoofers Reviews
JBL is one of the most trusted names in the loudspeaker industry. The company has been in business for a very long time and have mastered the art of making quality. They’ve released everything from home audio systems to headphones and maintained a level of quality throughout. The same goes for their their selection of car speakers and subwoofers.
The S3-1224 is one of the best free air subwoofers that JBL has to offer. It’s 12-Inch in size, and it can handle a decent amount of power on continuous basis.
The JBL S3-1224 is rated for a sensitivity rating of 92 dB, and can handle up to 500 watts RMS. It has a frequency Response of 25Hz – 175Hz and is suitable for both sealed and ported enclosures, as well as free-air use.
This JBL 12 inch sub is incorporated with an oversized three-inch (75mm) voice coil, allowing the subwoofer to be relatively lightweight compared to subwoofers with four-inch voice coils, and capable of handling more power than conventional two-inch voice coils. This strikes the perfect balance between thermal power handling and low mass.
Speaking of thermal management, this JBL free air subwoofer sports an advanced aero-cooled voice coil design which ensures long term reliability and consistent performance.
What sets this 12″ free air subwoofer apart from other subwoofers in the market is the SSI (Selectable Smart Impedance) technology that it’s featured with. SSI lets you select the optimum impedance —2 or 4 ohms— by simply flipping a small switch. This allows for greater flexibility and a variety of system configurations.
All in all, if you’re looking for a reasonably priced free air subwoofer with more power, more reliability, more flexibility — and no compromises, then JBL S3-1224 is for you.
Kicker is another well-established brand in the car audio industry. They’ve been in business for a very long time and have mastered the art of making quality car audio products for a reasonable price.
Kicker offers everything from car speakers and subwoofers to car amplifiers and signal audio processors. Most of their car subwoofers are designed to be as universal as possible. Therefore, they can be mounted in sealed or vented boxes as well as on an Infinite Baffle (freeair).
The 10C104 is one of the best free air subwoofers in the Kicker Comp series. This 10″ subwoofer is built to give you all the hard-hitting bass you could want in a sub without spending a ton of cash.
This woofer is built on tough steel basket which provides a reliable foundation for big bass. It features a thick injection-molded polypropylene cone with ribbed foam surround. The ribbed foam surround offers long excursion and keeps the cone on target, while the double stitching ensures your sub won’t come apart at the seams.
This versatile sub sports a strong motor structure with extensive venting to ensure long-lasting performance. Its 4-ohm impedance makes it compatible with just about every amplifier on the market.
Our main complaint about this subwoofer is that it can only handle 150 watts RMS and has a relatively weak sensitivity rating (86.2 dB). Depending on your setup, this sub might not give you enclosed sub levels of bass. Nevertheless, it’s still a decent subwoofer for the price.
They offer a wide range of car audio components including speakers, subwoofer, audio processors, amplifiers and accessories. They’re best known for their top-notch car subwoofers.
The 10W0V2-4 is one JL Audio’s best free air subwoofers. Being featured with cutting-edge technologies such as optimized motor system that promotes precise, linear cone movement, plus advanced cooling throughout the frame for rapid heat dissipation allow this free sub to deliver trademark JL performance.
Additionally, this 10″ free air subwoofer sports a tough polypropylene cone that’s bonded to durable foam surround for controlled driver excursion. Speaking of which, the cone’s extra-long excursion capability allows it hit truly deep lows with minimal distortion, while the beefy 2-inch voice coil drives the woofer accurately for extraordinary power handling.
Speaking of power handling, this subwoofer can handle up to 300 watts RMS which is more than enough to fill your ride with solid, clean tight bass bass.
So, if you’re looking for stellar performance at an affordable price, JL Audio 10W0V2-4 is for you. It’s one of the top rated free air subwoofer at this price range.
A brand that pioneers in the car audio industry is worth the trust you’d put in a product that carries its logo; Pioneer is one of the top rated car stereo brands out there. They’re as old as history. They’ve been in business since 1938 and have mastered the art of making top-notch products.
Pioneer was founded as a radio and speaker repair shop. However, over the years, It grew into one of the most popular audio brands in the car audio market, offering a wide variety of car audio components.
Pioneer offers a wide range of car subwoofers of different types and sizes; Their car subs are modestly priced for the most part. They are not the best sounding car subwoofers out there, however, they get the job done without breaking the bank.
Pioneer offers a few great sounding free air subwoofers for those of you who are into Infinite Baffle setups. What sets these subs apart from the rest is their low/shallow mount profile.
Pioneer Shallow Mount subwoofers comes in 8″, 10″ and 12″ sizes. They can handle up to 150 watts, 300 watts, and 400 watts RMS, respectively.
These subs are featured oversized MICA injection-molded resin cones that provides greater cone and gasket surface without changing the sub’s standard external dimension. These cones allow the subwoofer to produce louder and deeper bass by moving more air.
These shallow mount subwoofers are designed to perform in small enclosures or spaces that traditional subwoofers can’t fit. Despite their low mounting depth, these subs can deliver the big bass performance of a full-size subwoofer.
The Tropo 12″ Free Air D4 Subwoofer is one of the best free air subwoofer that CT Sounds have to offer. It’s jampacked with advanced technologies that allows it to offer stellar performance while keeping your wallet intact.
This 12″ fre inch sub is incorporated with Y35 graded triple stacked ferrite magnet, which in conjunction with it 3″ voice coils and a stupendous arm styled basket frame allow this subwoofer to deliver quality SPL performance.
Speaking of performance, this subwoofer sport SPL rating of 90.9 dB and can handle up to 450W RMS.