Every now and then We get e-mails and comments from car audio enthusiasts who like to rock out — really loud and hard. One recent one asked, “What’s the best position for subwoofer in trunk”.
Well, subwoofer positioning has always been a topic of heated debate amongst bassheads in the car audio community. No matter what kind of vehicle you have or what kind of subwoofer system, placement of the subwoofer enclosure DOES impact the sound.
So, whether you already own a killer subwoofer or are in the market for a brand new beast, knowing where and how to place it can make a huge difference. Not only where you put the box, but also which way you face the subs themselves.
With a wide variety of positions available, getting it right can be harder than it sounds. So, which direction should you point your subwoofer when it’s located in the trunk? Let’s find out…
Which Direction Should You Point Your Subwoofer?
Well, the short answer is that there’s not a single “best” direction. When it comes to car audio, it’s never the case that one size fits all. There are however, several factors that come into play when determining which direction yields the best results.
These factors include but not limited to your musical taste, your individual preferences, the type of your enclosure or subwoofer setup, not to mention your car’s make and model.
It goes without saying that experimentation is the name of the game. I mean think about it, every vehicle is built differently. This creates noticeable differences in the overall sound of the subwoofers and speakers you install. Therefore, it takes trial and error and lots of rigorous experimentation to determine which direction works best for your vehicle.
Furthermore, it must be noted that not all bass frequencies travel equally within a chamber. The placement of the subs will depend on the listener’s position and preference. A position that is not that loud at 40HZ may probably be really loud at other frequencies and vice versa.
In fact, you should bear in mind that there are two things working against each other when considering where and which direction a subwoofer fires.
First, there’s loudness which comes from the amplitude of the sound waves (vibrations). The closer it is, the louder it will sound.
Then, there’s phasing. When a subwoofer emits a spectrum of frequencies (sound), it radiates in all directions. And since hard surfaces reflect sound like crazy, the sound will bounce off any hard surface and radiate back at you. The problem arises when these radiating waves mix with the original waves and start amplifying/canceling out each other.
As mentioned above, in a particular position, you may find that certain frequencies are very boosted while others are basically non-existent. This can influence the original sound to nearly double its amplitude or nearly eliminate its amplitude completely.
The best approach to overcome the issue of phasing is to position the subs as far back as possible near the rear wall.
You can also position the subs to face toward the rear wall, up, toward you, or even sideways. You must, however, bear in mind that the closer the subs to the rear wall, the more in-line and less devastating the reflections are.
Facing the Boot – Rear of the Car
This is one of the best position for subwoofer in trunk, and it’s one f the most common direction used by most car audio fanatics. It allows for great bass performance, and great dispersion of sound.
This might sound counter-intuitive, but by placing the subwoofer in the trunk against the rear seats, facing away from the driver, the bass becomes more pronounced and evenly distributed across the car’s surface area.
Bass waves are omnidirectional and spread out in all directions. So, aiming the subs to the rear will significantly increase volume as bass frequencies build up in the rear corners causing sound decibel to rise. Arguably, this is good for volume but it’s not the greatest for sound quality.
Facing the subwoofers rearward (with the box against the rear seats) however is by all means better than any other position. It’s best suited for those of you who like to feel bass as much as hear it.
The reason why rearward-facing subs tend to work best is because the frequency of a wave is inversely proportional to its wavelength. What this means is that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength.
So, facing the subs backwards means the distance traveled by bass notes is that much further. For that reason, lower frequencies benefit in-cabin.
If you love listening to bass heavy music, or that you simply love to boost the bass frequencies with EQ, having your subs face backwards against the rear seats is the best direction for you.
Another great (but no so convenient) variation to this position is to have your enclosure closer to the front of the trunk (optimally, within a foot) instead of being pushed far back into the trunk.
This allows for the rear wave to exit through into the cabin, as well as the front waves to reflect off of the trunk lid of the vehicle, and be reinforced by the rear waves.
Facing Sideways – Side Firing
Having the subwoofers tucked way in the rear right- or left-side corner of the trunk in another great placement for subwoofer in trunk.
Putting your subs in one of the corners allows for more of a surround bass sound effect. This is especially true when you have the subs mounted in a ported box.
Ported boxes by their nature are “boomy” (sound louder), while sealed boxes give tight clean bass.
Another great variation to this placement is to install the subwoofer in the rear side panel (or in between the taillights and the strut tower). This is referred to as “corner loading”, and it’s mostly used to save valuable space in the trunk. Some OEM subwoofers are mounted in the same position.
The reason why this placement yields great results is because there will be no rear sound waves that can interfere. Additionally, you will have hard boundaries to the rear, and sides.
Facing the Rear Seat – Towards the Front of the Car
Facing the subwoofer forward into the cabin is another great position for subwoofers in trunked vehicle, but neither so great nor so convenient in SUVs (more on this down below).
Unlike having your subs face backwards against the rear seats, inverting the subwoofers lets you feel the bass in your body like never before. The downside, however, is that when the subwoofer is firing forward, the sound waves have nothing to reflect off which substantially decrease SPL.
If you care more about sound quality than loud bass with huge peak from cabin gain, then pointing the subs forward right towards the cabin is your best option. I mean, think about it, why would you spend a ton of time and effort building and fine-tuning an enclosure only to ruin its great response artificially.
If you really need that much bass and volume, you’d be better off with more powerful amps and subs.
It must be noted however that in order to make your subs sound relatively loud when they’re facing forward, you’ll have to seal up the box from the trunk so that the sound waves from the rear of the subs cannot reach the front of the subs and cause cancellation. In other words, you must completely seal off the trunk from the cabin of the vehicle.P.S: The same holds true for subwoofers installed in the rear deck, and free-air subwoofer installs
To sum it up, the car you use and your personal music/bass preferences play a crucial role in determining the best place to put the subwoofer in your car. For this reason, you’ll definitely want to test your sub/box out in a few different positions and see how it sounds when powered up to get the best idea.
The positions we listed above aren’t by any means the only ways to arrange your sub within your vehicle. However, these should be on the top of your list of subwoofer positions to test out.
Lastly, sound-damping products like mats and foams are always highly recommended when you upgrade your stock sound system. A bass worth paying for is going to make your car rattle; a steel box (your car) isn’t acoustically perfect, and it’s not designed to withstand that kind of wattage. So, consider sound damping materials to ensure that all you hear is bass blasting in your face.