Front passenger footwell - Planning a sealed enclosure for a 12" sub

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Vehicle: 2024 Ranger Wildtrak Double Cab, UK RHD, built Feb 2024, 2.0 Bi-Turbo.

I'm planning a sealed enclosure for a 12" sub (Audison AV 12 D2 II — needs about 21 litres net, 88 mm mounting depth plus 30 mm rear clearance) and I'm looking at the front passenger footwell.

Before I start cutting MDF/PLY I want to know if anyone here has genuinely built and lived with a box down there, because two things are bothering me:

1. Airbag zones. My build data lists CN9AB0 "NAS knee bolsters – passenger" and CP8AB0 "inflatable knee bolsters – driver", so on paper my passenger side is a static bolster rather than an inflatable one. Can anyone confirm that's how UK/EU Wildtraks are actually built? The BEMM for P703 shows a passenger knee-airbag envelope of roughly 540 x 400 x 170 mm and a front-airbag envelope of roughly 630 x 550 x 600 mm reach, and a normal upright box parks itself right in the middle of both.

2. Whether an angled box is a real solution. My thinking is a wedge sitting on the floor — roughly 420–450 mm wide, 450–520 mm along the floor, 180–220 mm tall at the rear, 100–140 mm at the front, driver laid back at 25–30 degrees firing up and rearward. That keeps the vertical profile low and out of the deployment cone, in theory. In practice I don't know if 21 litres net will physically fit under the glovebox once you account for the heater ducting, the wiring loom and the seat rail.

Questions:
- Has anyone built a footwell or under-glovebox enclosure in a T9 (2023 onwards) Ranger? Photos and dimensions would be gold.
- Did you make a clearance buck/template first, and how much usable depth did you actually find at the floor and under the glovebox?

- Did an installer or MOT tester ever flag it as an airbag obstruction?
- Anyone got measurements off the passenger knee bolster area, or a photo with the lower dash trim removed?

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Would this ai design work? your thoughts

 

[Stu x 4]

My $.02 just opinion.
When playing in bands; bass fills the room. Not directional. The cabinet can be placed almost anywhere. The tweeters or higher frequencies "are" directional. This is why you will see curved cabinet housing for the higher frequencies and on top of the PA stack to get over the upfront crowd.
I'm guessing you want a bigger cone to deliver more bass.

 

[hand-filer]

What is wrong with the under the rear seat enclosure location? Way more practical than effectively eliminating front passenger seating capability.

 

[popupstands]

Bass may be largely non-directional at the very lowest frequencies, but non-directional does not mean position-independent.

In a car, the sub is exciting a small enclosed cabin, not playing into an open field like a PA system. Moving the enclosure changes boundary loading, reflections, standing-wave modes, and—most importantly—the peaks and nulls at the driver’s ears.

An under-rear-seat enclosure can absolutely be a practical and effective solution. There is nothing inherently wrong with it. But it will not necessarily produce the same response as a front footwell sub, because the rear-seat location has a different distance, boundary environment, and acoustic path to the front occupants.

A passenger-footwell sub can make a dramatic difference because it places bass energy much closer to the front listening position and couples it to the floor, firewall, and side boundaries. Depending on the vehicle, that can increase output in certain frequencies and avoid a cancellation that exists with a rear-mounted source.

It also helps the upper-bass/midbass region blend with the front doors. Roughly 70–150 Hz is where much of the kick, bass-guitar attack, and punch live. That range is much more sensitive to timing, phase, and location than deep 25–50 Hz sub-bass. A rear sub may play plenty loudly, but a front sub can make the bass line sound as though it belongs with the front stage instead of arriving from behind you.

The PA analogy is only partly applicable. In a venue, subs are often placed where they are practical because the space is large and listeners are farther away. But even in live sound, sub placement matters greatly—engineers use placement and arrays specifically to control cancellation and coverage. Inside a car, the cabin is tiny, reflective, and irregular, so those effects are even more pronounced.

And no, the goal is not automatically a bigger cone. Cone area, excursion, enclosure volume, amplifier power, and tuning determine how much deep-bass output is possible. The point of a front-sub setup is mainly better response and integration at the front seats—not simply more volume.

Under the rear seat may be the more practical location because it preserves passenger foot room and may allow more enclosure volume. It can work very well. A passenger-footwell sub sacrifices some practicality, but it may produce much better front-seat impact and smoother integration with the door speakers.

Neither location is universally best. The cabin is part of the system. The best location is whichever one measures and sounds best at the driver’s seat after crossover points, polarity, time alignment, and EQ are properly set.

“Bass is non-directional” is true only in the sense that very low notes are hard to localize. It does not mean the subwoofer can be placed anywhere with identical results.

 

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I am having A-Pillars made currently and this is what I hope they will look like once i spray them

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