# Saving trunk space and mounting subs in cabin



## seismicboom (Jan 25, 2011)

Anyone have experience with subwoofer placed in the cabin of a sedan on the rear deck?
My idea is that it should be the same as if it were mounted to the rear deck with an enclosure hanging in the trunk.

I want to add subwoofer without looking trunk space or it costing to much.


----------



## jnchantler (Apr 11, 2012)

seismicboom said:


> I have a s sedan which Want to add a subwoofer.ive thought about custom fiberglass in corner of the trunk. Its a bit pricey .so im thinking 2 shallow mount 8s on top of the rear deck in sealed enclosures.questions are anyone have experience with this ?hows it sound?
> I dont want to wast the money on it and it ends up really crap.


What type of car is it?


----------



## fcarpio (Apr 29, 2008)

seismicboom said:


> Its a Sub compact sedan, has no holes in rear deck .


Year, make and model dammit! 

There may be something already available for it. Besides, what makes you think that custom fabrication like what you want will be any cheaper?


----------



## seismicboom (Jan 25, 2011)

Its a base model chevy sonic sedan no factory amp thing dosent have rear door speaker or a fade option on the headunit.

Just looking for input


----------



## sqshoestring (Jun 19, 2007)

IB subs would work the best, I have even put them in hatchbacks before. No box at all.

It would take an expensive sub in a box large as would fit in my trunk (and the weight would slow my car down lol) tuned at 30hz to equal the pair of cheap 15s into my back seat. Meantime I can use 95% of my trunk and nothing in my back seat or rear deck. The deck is sealed off with ply that is where my amp rack is. They can hit 25hz no problem. They still work ok even with the trunk stuffed with stuff, you loose a little bottom end is all. But daily the trunk is empty anyway.


----------



## gregerst22 (Dec 18, 2012)

^^ this. 
If you don't need to fold down the back seats it would probably be better and easier to build and IB wall and run a single or pair of subs. The only space you'll use is whatever the back of the sub takes up. Which is usually not much unless you throw in a pair of IDMax15's lol.


----------



## DC/Hertz (Nov 27, 2011)

You might be better off with a simple ported 8. They only take up a cube and can easily be removed if needed. That's the cheapest and easiest option.


----------



## seismicboom (Jan 25, 2011)

Ib is out as so is any enclosure in the trunk besides fiberglassed in corner(which cost to much)

Ib out i need and use all my truck space .front to back top to bottom


----------



## jode1967 (Nov 7, 2012)

if you are going to use all the trunk space, then the enclosure would have to be fully inside the cabin. Then you are giving up cabin space, and possibly window views


----------



## gregerst22 (Dec 18, 2012)

seismicboom said:


> Ib is out as so is any enclosure in the trunk besides fiberglassed in corner(which cost to much)
> 
> Ib out i need and use all my truck space .front to back top to bottom


If your willing to give up the spare tire you could glass a sub enclosure in there and possibly not loose any space at all. 

A reason you don't see very many people hanging subs off of the rear deck is because it can be very hard to do it right and generally not worth the work it would entail. The metal is usually not flat and is flimsy. It would need to be reinforced, there's not much room to work with because of obstructions such as hinges and rods. Not to say it can't be done as some people have it just more difficult than other alternatives.


----------



## DC/Hertz (Nov 27, 2011)

gregerst22 said:


> If your willing to give up the spare tire you could glass a sub enclosure in there and possibly not loose any space at all.
> 
> A reason you don't see very many people hanging subs off of the rear deck is because it can be very hard to do it right and generally not worth the work it would entail. The metal is usually not flat and is flimsy. It would need to be reinforced, there's not much room to work with because of obstructions such as hinges and rods. Not to say it can't be done as some people have it just more difficult than other alternatives.


That was my thought now. False floors work great with enough cone area. And it can be easily covered. Not the cheapest route but probably the best.


----------



## sqshoestring (Jun 19, 2007)

I put a bunch of subs IB in decks, it was the old school way. Not that bad long as you can fit in the trunk and do it right. I might be getting a little old to get excited about doing that now lol. Through the seat not as bad you can pull the seats and work in there some of the time. You can even offset subs or put in larger than your deck will hold. I usually bottom mount unless I have issues.

You want to do a deck you have to deal with rods, or get lift cylinders, but often you can fit the sub around the rods or move the rods a little. Take cardboard and make a pattern under the deck for ply. Cut the holes needed in the deck usually snips do it fine. I like topper foam to damp the wood to what is left of the deck. Screw the wood in much as you can from above with a drill/driver, go under and do spots you cant get or bolt them. I like 3/4 ply, you can shoot drywall screws into it pop pop and you are done. Drill starter holes if you need. Mount the subs, you can do that before you do the board if clearance is no issue or temp mount the board. Its easier to install subs if the holes and stuff are there already. Rebuild the top cover. Plug any obvious holes to the cabin from trunk that are near subs. Check for rattles once running.

The issue for me with IB is I get TONS of deep bass I like with IB. It makes the hassle so worth it. It is certainly easier for me to whip up a sub box than make a baffle and install IB. But IB takes only the basket of subs out of your trunk, it is much less weight than a box, and thunders like a low tuned ported. Generally you can run larger or more subs for better or equal output to any box you can fit in your trunk with 1-2 subs. Sure you can go high dollar/high wattage subs in a box and really blast, so do it that is great, but my 15s do more than I need most of the time and they do it at 30Hz. Trunk is empty and I don't have to mess with anything. I have a box I can unplug/remove in another car and it is way less pleasing all around. But yes, I worked on it for weeks here an there, it was a project to install. Now I'm pissed as its getting time for a new car.


----------



## fcarpio (Apr 29, 2008)

seismicboom said:


> Its a base model chevy sonic sedan no factory amp thing dosent have rear door speaker or a fade option on the headunit.
> 
> Just looking for input


IB mounted on the rear deck with the subs inverted (magnet up towards rear window), no trunk space used at all. Your car is like this, right?










Like this but with the magnets facing the other way.











You could use shallow subs so they don't stick out too far out.


----------



## seismicboom (Jan 25, 2011)

Yes thats my car I dont want to cut the deck ,is why im thinking just unstall the subs ontop in a shallow sealed box


----------



## Swaglife81 (Oct 15, 2016)

Some of the king cab, quad cab, 4 Dr truck guys build rear seat hump enclosures or rear console enclosure. Pics below to give you some ideas. I use alot of my trunk myself and debated this type enclosure in my G35 Sedan


----------



## fcarpio (Apr 29, 2008)

seismicboom said:


> Yes thats my car I dont want to cut the deck ,is why im thinking just unstall the subs ontop in a shallow sealed box


Seems like you already know what you want. What about a passenger footwell enclosure?










This is in a Miata. You would have to protect the sub a little better than that.


----------



## TallTexan (Dec 14, 2007)

My Impala has a bench like seat in the back enough for three people, but really for two. The bottom cushion is just a big blob of covered soft foam that can easily be removed. Mine measures out approx 55" long by 18" wide by about 6" high with some additional height carved out of the center/middle.

My first idea was to replace the whole lower seat with a FG box leaving just an inch or so at the top for padding and covered in vinyl with two shallow subs on either side ported out slots in the front (behind ones calves when you sit). The top begin solid/padded so I can still put groceries (and people) in.

Now I've some more thinking and redesigned it as a push/pull (isobaric) with one of the 10" in the middle with the other hidden below it leaving the two side seats pretty much alone. This way I can also put a slight hump in the middle and a metal grill on the top most exposed sub and not loose back seat relative comfort and room. The middle area measures roughly 13" x 18" x 8" which is roughly 1 cu ft. Its also not a permanent modification and I can always take the sub out and put the old seat back in.

FYI my current FG sub is in the rear corner similar to fcarpio's pic above.


----------



## seismicboom (Jan 25, 2011)

Yea was just tryng to see if anyones done this and could tell me how and what it compares to ..


----------



## Bnlcmbcar (Aug 23, 2016)

I have 2 SI BM mkV subs i want to mount in a Civic Sedan.

These are SQ subs that favor sealed boxes and fear I will lose valuable SPL placing them in the trunk.

So I have been thinking about ways I can place them as close to me (driver) as possible. It seems like the most unused place in my cabin is the rear bench middle seat...

I am contemplating a sealed enclosure that fits on the middle seat with whatever remaining cuft needed extending back through a ski hole passage. Each sub would be firing out from the middle seats towards each passanger door..

It would be a challenge to secure it but acoustically doese this sound like a good idea or no? Any input or feedback?

*I attached a rough sketch (I really can’t draw) of what I’m trying to describe.


----------



## Bnlcmbcar (Aug 23, 2016)

Change of plans, anyone have experience using a sealed encloser like the pics attached:


----------



## Jroo (May 24, 2006)

Ive seen the rear seat done two ways in a sedan. First sedan had a ski pass and fold down arm rest in the rear seat. That person pulled the arm rest out and built a sealed enclosure in that space leading to the ski pass. I think it was a single 10 sealed. 

The other I saw, same concept, but didn't have a ski pass or arm rest. That person basically cut the foam out of center of the seat down to the seat frame. They built the box and had it tied into the seat frame and then had it reupholstered to make it match up. It was either an 8" or 10"


----------



## Bnlcmbcar (Aug 23, 2016)

Did they sound good in your opinion?


----------



## Jroo (May 24, 2006)

both sounded good. Same output you would get with a normal 8 or 10. Obviously the one without the ski pass took more work. Ive looked at something similar in my car but space would not give me enough box volume. I could only fit a 6.5 sub in the space. Wouldn't be enough output for me. I am currently looking at doing IB in my car


----------



## WilliamS (Oct 1, 2016)

Take a look at the rear deck, there might be cutout for speakers there already. If so what size and put a couple of sub based speakers in there. I did that with my 76 monte carlo back the 90's. It had 2 6x9 cutouts, I put the best at the time in those spots and a small 200watt amp and it was more than enough to make the music clean and a little rumble in the seats.


----------



## mcgsxr (Jul 19, 2018)

I built a small sealed box for a JL 10TW1 for my CLK cabriolet. I put it in the passenger footwell directly behind me.

It lacks a little output in my convertible (I miss cabin gain), but when I tested it in my Ford Fusion, it was the output equal of my old Orion 12 in a 1 cubic foot sealed box.

Worth considering, if you don't often move 4 people in your car. It also helps if you're short like me!

My woodworking is solid. My carpet work (even when assisted by my daughters) leaves a LOT to be desired. Thankfully it all blends well with the black interior of the car, and only looks brutal when removed!


----------



## Bnlcmbcar (Aug 23, 2016)

mcgsxr said:


> I built a small sealed box for a JL 10TW1 for my CLK cabriolet. I put it in the passenger footwell directly behind me.
> 
> It lacks a little output in my convertible (I miss cabin gain), but when I tested it in my Ford Fusion, it was the output equal of my old Orion 12 in a 1 cubic foot sealed box.
> 
> ...


I’m liking the idea of this. My enclosure for each sub would be .5 -.7 cuft. Each rear foot well can work. I’m even the type that would provide myself enough wire slack so that I can quickly/temporarily move a box to the the trunk in case of having rear passengers.

Thanks for the input JRoo. I’m also tempted to do a faux IB install as well. Since the BM’s don’t like IB, I was considering making a dual chamber sealed box that is forward firing but sealed to the cabin like an IB baffle would be. The rear deck would also be sealed off.


----------

