You can do this, but I would make something to replace the factory carpeted bottom piece. Maybe a piece of hardboard or MDF, with acoustical carpet, and the area where the sub vents into the cabinet cut out and covered with chicken wire under the carpet. It affords you the space you desire and promotes better output from the sub. That is a lot of work though. There are a ton of YT videos on the subject and how to do it right.

https://www.youtube.com/results?search_query=+subwoofer+in+the+spare+tire+cavitiy

 

You can do this, but I would make something to replace the factory carpeted bottom piece. Maybe a piece of hardboard or MDF, with acoustical carpet, and the area where the sub vents into the cabinet cut out and covered with chicken wire under the carpet. It affords you the space you desire and promotes better output from the sub. That is a lot of work though. There are a ton of YT videos on the subject and how to do it right.

https://www.youtube.com/results?search_query=+subwoofer+in+the+spare+tire+cavitiy

I don't want to make any modifications, so I'm trying to figure out the downsides, if any, to having the sub box in a secondary enclosure (i.e. under that plastic and carpeted lid). As you mentioned, I figured there might be some (minor?) output reduction but maybe not in the frequencies below the crossover.

 

Just make a new top panel and vent it with some expanded mesh flush into the top and carpeted over. Any automotive carpet will do for a sub. You may even be able to strip the carpet off that panel and vent it then re-carpet.
Mine looks like this under the trim panel.

And looks like this with the vented panel in place.

 

Just make a new top panel and vent it with some expanded mesh flush into the top and carpeted over. Any automotive carpet will do for a sub. You may even be able to strip the carpet off that panel and vent it then re-carpet.
Mine looks like this under the trim panel. View attachment 408934

And looks like this with the vented panel in place.
View attachment 408935

That's a really nice stealth enclosure. I don't want to make any modifications to or replace the top panel.

 

I had this done in my Lexus years ago (2008) and it’s the best install I ever have had. I think it was a 13” w7 but idk it might have been a 12” (not sure if they even made a 13”). But yeah it was always covered up and it took effort to get the rattles silent, but it was perfect sound. They used fiberglass in the tire well and just sealed the whole thing. I recommend.

 

You'll just need to pick a sub that works well in limited space/low enclosure volume. You'll need to measure what mounting depth you're working with. In space-limited enclosures you may have to go with a smaller sub or even a shallow mount one. It's not going to give you crazy big booming bass compared to a bigger enclosure with a big sub, but you can still have a good sounding system.

You'll want to build a box to fit in the space. You may be able to seal the space instead but I'm not familiar with this or the difficulty.

You could get fancy and go IB, but that's a lot of work.

 

You'll just need to pick a sub that works well in limited space/low enclosure volume. You'll need to measure what mounting depth you're working with. In space-limited enclosures you may have to go with a smaller sub or even a shallow mount one. It's not going to give you crazy big booming bass compared to a bigger enclosure with a big sub, but you can still have a good sounding system.

You'll want to build a box to fit in the space. You may be able to seal the space instead but I'm not familiar with this or the difficulty.

You could get fancy and go IB, but that's a lot of work.

Installer wants to put a JL truck wedge with a 12" TW3 in that space.

Custom box pricing I've gotten for the spare tire space has been insane compared to just using the pre-loaded JL box.

 

I have an empty spare tire space in the back of my SUV where I could put a sub. Advantage of using this space is that I won’t loose cargo room. The space is covered by a carpeted plastic lid (picture below). Seems to be some type of honey comb plastic composite about 1/2” thick. It seems solid, but not dense. The sub will have it’s own box, and I’m guessing there will be about 1-2” of space between the driver and the lid when the lid is closed.

So, will I be sacrificing any sound quality by having the sub in that sealed space? Would it be better, sound quality wise, to have the sub sitting in the cargo space instead?

I can't quite tell what model/brand SUV you have, but I bought mine to do long trips in (Camping, etc) and although I love the idea of being stealth and not having a big-azz Sub box in my cargo area, and not needing a ton of bass, based on my types of music, I opted to use one of my rear cubby areas to have a custom Sub box made/installed in. There is a picture in my Build Thread, as well as a YouTube video that my Installer made.

So if you are worried about not carrying a spare, this could be another option...

2019 Honda Passport: 10+1 Channels (Updated 9/24/2023)

As a Quality Manager and former Design Engineer, I have documented my build below. Keeping in mind my goal was not to make this an on-going hobby, constantly swapping components out and creating my own “Winchester House”, my goal was to upgrade the stereo and then stop, enjoy and get on with...

www.diymobileaudio.com

 

It's a BMW X5 (G05). I only fill the cargo space 1-2 times a year, which is why a sub box back there would be ok if it had quick disconnects. But spare tire area is preferred. Just want to understand the trade offs.

Unfortunately the side panels on this car aren't conducive to even 10" subs without starting to cut the panels up. I was fortunate with my last system that my Ford Explorer had an OEM sub already in the cargo area side panel. The installer removed it, enlarged the area a bit, then built a custom box and grill for a bigger sub. Looked factory.

From my reading this car seems to be a PIA when it comes to upgrading.

 

Thanks for the replies. Maybe a few more details will be helpful.

So the installer want to drop a JL power wedge in the spare tire compartment. I assume that the space will then be treated and the sub box secured.

JL Audio PowerWedge TW3 Enclosed Car Subwoofer | Garmin

PowerWedge™ TW3 is an enclosed car subwoofer with a compact enclosure design, thin-line drivers, available in 10- or 12- inches, and has a 2-year warranty.

www.jlaudio.com

The alternative is to use a standard sub box in the cargo space. Such as:

JL Audio H.O. Wedge W3v3 Enclosed Car Subwoofer | Garmin

H.O. Wedge™ W3v3 is an enclosed car subwoofer with a high-output enclosure design, All-Star W3v3 subwoofers, 10- , 12- , subwoofers sizes, and a 2-year warranty.

www.jlaudio.com

If I go with the standard box in the cargo space, then I'll have quick disconnects in case I need to put anything large in the space.

I prefer to have the sub in the tire compartment, but not if the plastic lid is going to mess with the sound quality. I get that I can have the best of both worlds by modifying the tire compartment lid, but that's just not an option at this point.

 

So the installer want to drop a JL power wedge in the spare tire compartment. I assume that the space will then be treated and the sub box secured.

PSA since it looks like you are a newer member, there have been a few threads where assuming a shop will do something doesn't end well. Make sure you get anything you expect done in writing on a quote. Hopefully you're already thinking that, but if not, have a thorough conversation and a detailed document covering the assumptions.

What are your expectations for the subwoofer? Do you want it to simply do a better job than the stock system or do you want to maximize sub bass volume? The HO enclosure will probably provide more output, especially if you prefer to not modify the spare wheel well / cover.

 

That actually a lightweight honeycomb corrugated/card material and the surfaces dipped with fiber/resin. Bass/sound will go right through it. I have a picture/cutout of it somewhere on one of the threads.

 

I was thinking that a fiberglass enclosure wouldn't be that difficult to make for that cut out. I've never heard of using corrugated cardboard, that's a really neat idea.

 

If the extent of your audio upgrades is just going to be subs that you may as well just go with the loaded JL box and call it a day. If nothing else you don't want your subs to outmatch the rest of your system, and I think the loaded JL box will probably suit your needs. Your sound will greatly improve.

 

Yeah, I’m leaving the speakers alone for now. Mainly because, again, there are so few good aftermarket options for speakers. Focal makes some that fit, but I had the K2 series in my last car and wasn’t a big fan.

So for now it’s amp, DSP, sub, and a good tune. Maybe in the future I’ll find some 4” mids and tweeters that are worth upgrading to.

 

I did the something similar. Output is subdued some on my setup. I can raise the factory cover a little bit and that helps output. It just needs some airspace to get to the cabin.

 

I did the something similar. Output is subdued some on my setup. I can raise the factory cover a little bit and that helps output. It just needs some airspace to get to the cabin.
View attachment 409366

Any idea what the cover of the spare wheel compartment is made of?

If you turn up the volume of the sub, does it sound the same as if the lid was raised?

 

if you only use the back a couple times a year, id get this and have someone build you a nice box

SQL Series 2 – StereoIntegrity.com

stereointegrity.com

 

Superb example of coming in hot with the first post. 👏