Tommy B

I was looking to put a small sub into the car and realized that the back seat is cramped enough and the trunk is useless. Except for the amp. The other day while i was driving i noticed a large mount of wasted space in the passenger footwell.

I remembered an audiofile show winning BMW that had subs in the front wheel wells and the idea clicked.

I'm thinking of building the sub right into the well and covering it such that the passenger can put their feet right onto it. For the box itself i was going to fabricate it in fiberglass so that it will fill the contours of the space most effectively. It would resemble the JL "Stealth Box" concept.

For the covering i was thinking a plexi cover over the sub for looks and diamond plate over the rest. Then i could make a snaller diamond plate footrest for the drivers side to balance the look.

I'm on the fence though, that may be too flashy, so i may just make it black and thow my floormats right over it.

What do you guys think? Flames welcome.

JBrown

Tom have you worked with fiberglass before? what you want to do is not that hard. As long as you have had exsperiance with molding a box with fiberglass. Remember you still have to make the box to a certain cubic footage for the woofer you are going to use. i am not a big fan of diamond plate unless it is for a truck but not in a porsche. do it in fiberglass and rap it in vinyl. They make all kinds of vinyl in colors or carbon fiber tecture. I did my own 911 door panels in black carbon fiber look vinyl. Good luck any questions www.soundfxny.com

Tommy B

i did a very similar fiberglass box for the hatch of my golf. i basically molded it into the area behind the wheel well.

in regards to cubic area, i will oversize the depth of the box and when it's dry fill it with water to get an approximate volume measurement. for a sealed box, most 10" only need a little more than a cubic foot.

I built the one in my golf with a 12" and it wasn't quite as tight sounding as i would have liked. I figure the 10" or maybe even a ported 8" will be fine since the box will be so close to the listeners

2002M3Drew

There is an ad in Panorama for a company that sells replacement rear decks, one of which effectively holds two 6x9 speakers. I would guess you could put subs in there and put separates in the sides to round out the sound, or just use the fronts to set the soundstage. Even good full-range 6x9 units have pretty decent bass by themselves...that might be enough for you. The box came in vinyl or leather.

Russ L.

Tommy;


Congrats' on your new purchase... I hope you got what you were looking for in a "p-car"!
Anyhow... There are a few things to keep in mind if you're going to even install a sub in ANY vehicle: 1] Can your alternator hold up to the stress of something pulling big amps from it... You may think about a "cap" installed in the trunk as well as the amps. to kind of buffer the abuse.
2] Vibration from a sub can/ will "shake up the entire car...meaning that if you look at your fuse box you will see that the wires are held down by "screw blocks". I know from my own cars that these will loosen up without the extra vibration of a sub resonatiog @ 30/125 cycles...and if you like to "THUMP" YOUR MUSIC ... Be raedy to "loose certain items in your elec. system at ANY given time! Sure it sounds GREAT when you feel the bass more than you hear it...but is the tradeoff to your liking?
If you're mechanically inclined... just tweek the setscrews on ALL the posts to insure they are making good contact,and go from there!
3] I have a shop that was going to put an 8" JL right where you're thinking about doing yours... They are Classic Audio in Bohemia N.Y. I've been the automotive trade and have known Henry and Jason for the better part of 25 years...and I would not bring my car to anybody else for audio.
Threr are other ideas that we've toying around with but E-mail me if you have any other ??? RUSS

jlkline

I have a bazooka cannon that I bungee (?) mounted to the inside of the luggage compartment pointed at the cabin. All the bass you really need plus still plenty of storage in the boot. I have a set of connectors there as well in case i ever need to temporarily disconnect it for additional storage, which I haven't needed yet. 200 W amp is mounted under the driver seat with channels 3/4 driving the sub.

Russ L.

B.T.W. Tommy my e-mail is FLOYD1960@OPTONLINE.NET
Also I just saw the post about a 10" .... If you're going with a "top of the line" JL ...the depth of the sub itself mat be a concern.... unless your pass. has 2' long legs lololol!
The guys @ classic and I were bumping heads about this and figured that the back seat is nothing more than a large cargo tray anyway so if we made a box that resembled the seatbacks folded down [mine is a cab.] and set twin 10's or 8's in the "wells" where the seats were! I think it would still look stealthy...and still give you the same room as if the seats were down in the first place!
The way I'm going with the fronts : JL 3-way 6.5" in the door panels if the depth is good behind the panels, 4.5" mids mounted on the inner panels just below the ends of the dash oneither side...and 1" tweeters mounted on the upper front dash. This will seperate the frequency ranges well as well as use the windshield to reflect the highs to your ears much better than keeping all of the sound in the door panels.
If you're thinking about the add-on panel in the back...it should work ok...but use a REAL good set of 6x9's. I'd go with MB Quart myself. I have a set of these in my old Jeep Cherokee all the way in the rear hatch with NO amp and they will kick my back when I Turn it up....and they DO NOT DISTORT!!!! I listen to anything from Yanni to Pink Floyd to Blues Traveler...to Frank Zappa !!! and all in between. These will not let you down. Good luck ! Russ

JBrown

tom most 10 woofers reqiure about .5-.75 qft. 1ft is to big and will be sloopy. depending on what sub or subs you use will determaine how much power you will need to drive them. If you are going modest with power like 200-400 watts rms that will not be a to hard on your alternator. as long as your electrical system is in good shape. a capacitor is good to add it charges and discharges very quickly so it is always nice in any system to help keep the volatage steady. I have did systems up to about 160dbs which is crazy. you also say small sub if you are going with 8 or 10 and you are using 1 you should have no issue with loosening anything up in the car. Unless you are talking w7 or comparable speaker by other manufacture. by the way i have 21 yrs exspieiance and i was out in rockford fosgates manufacturing plant in arizona last yr and went thru a Top gun training with Mark Fakuda. Who is probably one of the top 5 installers in the world

Tommy B

I'm using an old fosgate i have that is bridged to 250W. Nothing too crazy. I'm gonna take some measurements this weekend to see how much room i have to work with.

r911

The box needs to be rigid and damped -- don't use fiberglass, use MDF and glue carefully as well as screw. There are books and web articles on making generic sub enclosures as well as calculators - size is critical.

Check out Paris Audio (web site) who make a footwell sub for the passenger side of Boxsters. There or the smuggler's box (search Pelican Bd for "bell" and sub) will not harm th ewt. dist. as much as a back seat one.

Also realize that this thing will be heavy and that does not go well with a sports car.

Tommy B

not sure what you mean by damped? in terms of rigidity, i will first lay fiberglass cloth to form to the contours. once that cures i can pop the enclosure out and build up the inside with bodo with glass fibers in it. i then will cut a piece of mdf fot the speaker mount. first i screw the box to the board and then i fill all openins with more glass putty.

my golf's enclosure was about 1/4 to 1/2 thick and was extremely rigid.

About weight, it weights less than my girlfriend and i take her in the car. if i go to the track, i'll leave her and the box home.

JBrown

you can use fiberglass but you have to no what you are doing, after you make your mold from the floor you are going to have to use fiberglass matting to build up the mold for strength, depending on what woofers you use would. if you are using the rockford amp and it is rated at 250 rms i would say you need to go about 1/4 to 1/2 if you really want to be on the safe side. then you are going to use wood as the baffle plate which is what the woffer is going to mount to and you want to use 3/4 MDF. You can call me at my store soundfx 845-356-8606 (john) and i can step you thru it. there is only one way to do this and that is important , If the box has leeks or if it is incorrect cubit footage it will not sound right

r911

YOu should check into some hifi speaker building books. Damped means the box will not resonate. For best sound quality MDF is used. Check out the expensive home subs -- you won't see any fiberglass because it will have panel resonance. Sure you can use it. But why not do it right.

JBrown

randy i no were you are coming from with using mdf but when you are working in tight spots in cars fiberglass is used in conjuntion with the mdf. JL audio who is the best at making stealth boxes uses only fiberglass in there stealth inclosers. Most car audio pro will tell you that they are supperb sounding boxes. Today there are a number of materials that you can use to dampen the box. If you pick up any car audio magazine you will see that every hi end sub incloser will have fiberglass incorperated into the design some how or another. Buy the way any hi end installer will tell you using fiberglass incorperated with mdf is the right way. maybe you have been out of car audio for a while but it has come a long way in the last 10yrs, as well as equipment.

r911

JB, Actually I am not into car audio at all. I am more into home equipment and like to stop just short of the bleeding edge....

By all means he should try a fiberglass enclosure with some added material to quiet down the fiberglass panels first. It will certainly be lighter. I repeat go visit Paris Audio and look at their subs for the footwells on new 996s.

Also think about using the smuggler's box -- go to Pelican forum and search on bell and sub woofer.

Good luck.