Sub in Jack Location
- Thread starter billyrohm
- Start date
fourthmeal
Banned
I too know that its been done in that jack location. Also, I was reasonably successful working on another wasted area of the car, and that was the space taken up by the foam blocking under the carpet. With fiberglassing, you can use this space to form a 10" slim-style sub box, all under the factory carpet for a truly stealth look.
I eventually gave up on this idea and stole the spare tire well, in an attempt to put a much more low-reaching 10" sub known as an LMT sub. This means I have the equivelant of a home theater sub in my spare tire well, and it works damn well. I just stuff the spare tire on top of the trunk area in a bag, if I am going on a long trip. You figure that this car has low pressure tire sensors, and therefore will provide you warning that a tire is low before it has reached a critical situation. This means you can add air, or get home and get your spare, in daily driving situations.
I'll be changing this eventually to work on a different solution, because I overbuilt the box and it weighs too much despite being mostly fiberglass. The sub itself weighs 40 lbs, and the box another 40 or so. I've gotta find a lighter sub that still gets close in performance. My tube amps are also a bit heavy, but wonderful to use, so I got to work on that too...
Oh, anyway, back on topic...
If you want, you can fab up a fiberglass box under the factory cover, flowing along the lines of the spare tire well. This would let you access the spare tire, have your sub, and have room for your amps on the other side. I can post pics if this is interesting to you.
I eventually gave up on this idea and stole the spare tire well, in an attempt to put a much more low-reaching 10" sub known as an LMT sub. This means I have the equivelant of a home theater sub in my spare tire well, and it works damn well. I just stuff the spare tire on top of the trunk area in a bag, if I am going on a long trip. You figure that this car has low pressure tire sensors, and therefore will provide you warning that a tire is low before it has reached a critical situation. This means you can add air, or get home and get your spare, in daily driving situations.
I'll be changing this eventually to work on a different solution, because I overbuilt the box and it weighs too much despite being mostly fiberglass. The sub itself weighs 40 lbs, and the box another 40 or so. I've gotta find a lighter sub that still gets close in performance. My tube amps are also a bit heavy, but wonderful to use, so I got to work on that too...
Oh, anyway, back on topic...
If you want, you can fab up a fiberglass box under the factory cover, flowing along the lines of the spare tire well. This would let you access the spare tire, have your sub, and have room for your amps on the other side. I can post pics if this is interesting to you.
Re the pics from CaSHMeRe...
There is MUCH more space back there than that picture indicates. I have the panels off in my car right now. The opening in the panel to the jack is deceiving. Remove the panel and you will see that there is easily enough room in there for a 10" sub. This is probably true for the passenger's side too. However, on the pass side the fuel filler neck is surrounded by metal, so it decreases the available space between the taillights and the "wheelwell". Probably enough airspace though. On both sides, there is room above the wheelwell and beneath the plastic support for the cargo cover.
If a person was willing to cut up the factory side panel(s) of the trunk, one could make an enclosure for a larger sub. Now, to get a guinea pig...
My other thought was an enclosure that fit inside the spare tire. Remove the crappy foam that elevates the spare tire and invert the spare so the wheel faces up. You will see that the inner diameter of the wheel is about 15-16" across and the wheel is roughly 5" deep. Fiberglass this and you have roughly 0.5 cubic feet. Given that the tire now sits lower, you now have some additional volume between the tire and false floor that you can use. If you assume a conservative 3" additional depth, you just gained another 0.3 cubic feet. So, at a minimum, you have about 0.8 cubic feet if you put a "box" in the spare and fire it up. Completely hidden from view and it can be removed for when you need your spare. Not to mention, the large magnet of your sub would set in the tire and not raise the floor a single inch. If you need even more volume, the space that fourthmeal mentioned could also be utilized.
If you are having trouble envisioning what I'm talking about take a look at this link.
http://ydant.com/subwoofer_construction/
Also, take a look at JLaudio's stealthbox design for the mark4 jetta/golf and new beetle. It is a sub that fires down into the spare tire well. The spare sits on top of it. Something similar would work in the Mazdaspeed3 too and the floor wouldn't need to be raised an inch.
-Mark
There is MUCH more space back there than that picture indicates. I have the panels off in my car right now. The opening in the panel to the jack is deceiving. Remove the panel and you will see that there is easily enough room in there for a 10" sub. This is probably true for the passenger's side too. However, on the pass side the fuel filler neck is surrounded by metal, so it decreases the available space between the taillights and the "wheelwell". Probably enough airspace though. On both sides, there is room above the wheelwell and beneath the plastic support for the cargo cover.
If a person was willing to cut up the factory side panel(s) of the trunk, one could make an enclosure for a larger sub. Now, to get a guinea pig...
My other thought was an enclosure that fit inside the spare tire. Remove the crappy foam that elevates the spare tire and invert the spare so the wheel faces up. You will see that the inner diameter of the wheel is about 15-16" across and the wheel is roughly 5" deep. Fiberglass this and you have roughly 0.5 cubic feet. Given that the tire now sits lower, you now have some additional volume between the tire and false floor that you can use. If you assume a conservative 3" additional depth, you just gained another 0.3 cubic feet. So, at a minimum, you have about 0.8 cubic feet if you put a "box" in the spare and fire it up. Completely hidden from view and it can be removed for when you need your spare. Not to mention, the large magnet of your sub would set in the tire and not raise the floor a single inch. If you need even more volume, the space that fourthmeal mentioned could also be utilized.
If you are having trouble envisioning what I'm talking about take a look at this link.
http://ydant.com/subwoofer_construction/
Also, take a look at JLaudio's stealthbox design for the mark4 jetta/golf and new beetle. It is a sub that fires down into the spare tire well. The spare sits on top of it. Something similar would work in the Mazdaspeed3 too and the floor wouldn't need to be raised an inch.
-Mark
Last edited:
fourthmeal
Banned
This was using an amp I later removed. But the idea is the same:
This was my orginal idea, a 12" slimline sub. I got very close to completion when I ended up winning an LMT sub on ebay. And then, I scrapped the box design to make the new LMT work.
This was my orginal idea, a 12" slimline sub. I got very close to completion when I ended up winning an LMT sub on ebay. And then, I scrapped the box design to make the new LMT work.
fourthmeal
Banned
synthetic suede, found at jo anns. I also put Ensolite (Raamaudio's soft closed-cell foam) under the faux suede, to add a slight padding to it. What you see here is actually scrapped, and I'm working on something else. Still, the suede stuff is sweet.
Thanks as always, guys.
Sounds like me. Finish something and then decide to redo it. I think I ended up having 8-9 different sub installs in my previous car. I was never quite happy. Then I just got tired.
fourthmeal
Banned
I can't recall any system I'd been able to leave alone. I learn a new trick, or want to try a lighter, or more space-saving way to get the same acoustic performance, and off I go.
To people wanting to use the sides as a sub location...If you REALLY want to capitalize on this, you should consider using the entire inner area. I didn't want to do it because I felt like it was the wrong place for the car to take on extra weight (the sides, and up high), but it would be very stealth.
You see, most good subs, the ones that play low (which is what a sub should be doing) also take a fair amount of space. All these subs that play in .5 cubic feet simply can't swing a low-frequency repsonse that will really give the music the depth that it demands. If you are after the airspace you will need to get the extension in range (out of a ported or sealed box), then you have to consider using a lot of room hidden inside the side panels.
Hoffman's Iron law: You can get low airspace, fast response, but weak bass output / high airspace, fast response, deep bass output / low airspace, slow response, but deep bass output. You can't get all three.
To people wanting to use the sides as a sub location...If you REALLY want to capitalize on this, you should consider using the entire inner area. I didn't want to do it because I felt like it was the wrong place for the car to take on extra weight (the sides, and up high), but it would be very stealth.
You see, most good subs, the ones that play low (which is what a sub should be doing) also take a fair amount of space. All these subs that play in .5 cubic feet simply can't swing a low-frequency repsonse that will really give the music the depth that it demands. If you are after the airspace you will need to get the extension in range (out of a ported or sealed box), then you have to consider using a lot of room hidden inside the side panels.
Hoffman's Iron law: You can get low airspace, fast response, but weak bass output / high airspace, fast response, deep bass output / low airspace, slow response, but deep bass output. You can't get all three.
If I could do an IB setup in this car, I'd be all over it. Ended up with an aperiodic 10" sub in the rear deck of my Passat. It wasn't overpowering, but reached really low due to the massive enclosure space. Not to mention, low Q.
fourthmeal
Banned
Yes, AP is the shiz.
Personally, I'm dying to try a 1/4 wave trans line.
Personally, I'm dying to try a 1/4 wave trans line.
I wouldn't do a 1/4 wave in a car. For a subwoofer your would need something like a 10 foot long enclosure with an output about 2/3 the surface area of the driver. Not really practical considering we have the benefit of cabin gain in a car.
I did a folded 1/4 wave for my 6.5" two-way home speakers. I tuned mine to 1/4 wl of the Fs. It extends very low, but the output isn't that high.
My buddy and I built a set for him too. In his case, we shortened the line. It sounds better to me. If you assume the tline is a sealed box, it will have an Fb, or resonant frequency in that box. The line length should equal 1/4 of the wavelength at Fb. The one thing with t-lines is that there are so many variables. So, you kind of what to pick a tuning frequency and make the length and volume of the line match up. Also, you want the exit port to be close to the surface area of the driver in question. So, this will also dictate what tuning frequencies you can choose.
Check out http://www.t-linespeakers.org/ it will answer lots of questions and also leave you with more.
-Mark
Did you see the IB setup on that Golf at diyma? What do you think of that? Think it would work in an MS3? Maybe it wouldn't be perfectly sealed, but the enclosure would be "light". Just imagine replacing the cargo cover with a stealth subwoofer baffle. Of if a true AP was desired, with two small fiberglass enclosures behind a pair of subs. Would be lovely. I'm just wondering if the cancellation or leaks would be too great.
-Mark
fourthmeal
Banned
I was talking about home use for t-line. BOSE proves to us that car T-lines just aren't practical. Interesting (Ala RX-7 waveguide) but not practical.
Now, IB in the MS3...too many air leaks IMO, and with today's subs and today's efficient amps, it is easier to get a decent sealed box in the car (stealthily.) Sedans like BMW and such excluded, of course because they come pretty tightly sealed out of the box.
Now, IB in the MS3...too many air leaks IMO, and with today's subs and today's efficient amps, it is easier to get a decent sealed box in the car (stealthily.) Sedans like BMW and such excluded, of course because they come pretty tightly sealed out of the box.
