If you look in the back of a friend’s car or SUV, you’ll find there are a few common traits when it comes to subwoofer system installation. For larger enclosures, the subwoofers are usually mounted behind the seat and fire rearward. For single-sub systems, many installations feature the drivers mounted in an enclosure that fits into the corner of the car. If you don’t want to give up storage space, the spare tire well becomes a popular mounting location. The question is, does the position of the subwoofer affect its performance? Let’s check it out!
The Test System
Not long ago, we set up a test to evaluate the need for equalization in a subwoofer system. We used an old Elemental Designs e12A.22 12-inch subwoofer in a 0.75-cubic-foot sealed enclosure and paired it with the ARC Audio 1000.4 that the BestCarAudio.com team had reviewed in early 2021. As the baseline for this article, we had the subwoofer enclosure positioned against the rear of the driver’s side back seat. The subwoofer was pointed rearward toward the hatch of this 2019 Hyundai Santa Fe SUV. We’ll use the equalized signal as the baseline. We’ve created a map of the cargo area and a representative rendering of the subwoofer enclosure to let you know where each measurement was taken.
For the purposes of this article, we’ll use the equalized output of our 12-inch subwoofer and ARC Audio amplifier as our benchmark.
Subwoofer Position Testing
The next step was to move the subwoofer around the cargo area of the vehicle and take additional measurements to quantify any changes that might occur.
The second position we tested found the subwoofer in the left rear corner of the cargo area with the driver facing inward. The green trace shows that we lost about 7 dB of output at 23 Hz, but picked up between 1 and 3 dB at all frequencies above 36 Hz.
The third position had the subwoofer flipped around and pointed at the outside of the vehicle. The response, shown with the orange trace, shows some gain at 23 and 26 Hz, along with the same increase above 36 Hz.
We then moved the subwoofer to center of the cargo area, right up against the hatch. We started with the subwoofer pointed toward the rear of the vehicle. The brown trace shows a bit of loss between 21 and 24 Hz and some minor gains above 36 Hz. The dip created at 60 Hz would need to be addressed with an equalizer.
We flipped the enclosure around to direct the subwoofer toward the front of the vehicle and took another frequency response sweep. The blue trace shows very similar changes to those demonstrated with the woofer firing rearward, but the bump at 64 Hz is gone.
The last test location has the subwoofer at the back of the cargo area, once again up against the seats, but this time with the woofer centered in the vehicle. The cyan trace is still close to our reference measurement in this mid-sized SUV, with some loss below 25 Hz and small gains from 36 to 54 Hz. The differences aren’t earth-shattering in any way.
To wrap things up, we tilted the enclosure onto its back with it still right behind the seats and centered in the vehicle. The gains from 36 to 54 Hz disappeared and there was a few extra dB of output above 60 Hz.
If it won’t cause you a headache, here’s a zoomed-in graph with all of the traces visible at once. They are all very close from 27 to 36 Hz and vary by 6 dB at most between 36 Hz and 65 Hz. Given the kind of bass-heads we are, we like the idea of some gain at 23 and 26 Hz, but it’s minute and isn’t going to turn this into an SPL competition vehicle.
It should be noted that these measurements are of just the subwoofer. There are no midbass or midrange drivers operating in the vehicle during the test. In fact, the factory-installed audio system was turned off. If you’re trying to blend the output of the subwoofer with woofers installed in the doors, then phase measurements might be worthwhile. Without repeating all the graphs, we can let you know that having the subwoofer in the back corner of the trunk facing the interior delivered the smoothest phase response of the test group. The second-best in terms of phase was with the subwoofer behind the seat and pointed upward.
Subwoofer system phase response: reference location, red; left corner facing inward, orange; rear middle-facing upward, violet.
We plan to repeat this test in other vehicles to see how a sedan with a trunk performs. We have a theory that things might be quite different. Stay tuned for that!
Upgrade Your Car Audio System with a Subwoofer Today!
When you’re at your local specialty mobile enhancement retailer discussing where to mount the subwoofer system in your SUV, you can refer back to this article as a guide. Ultimately, no particular location was a disaster and none stood out as a big winner. We’d lean toward having the sub in the corner of the cargo area firing toward the center of the vehicle, given the need to choose an optimal solution.
This article is written and produced by the team at www.BestCarAudio.com. Reproduction or use of any kind is prohibited without the express written permission of 1sixty8 media.
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