I am SubSam: 15" BtL N2 on 2230K

[SubSam 21]

So I should formally introduce myself, the name’s Sami O., I am a citizen of the mighty (or mightily small) country Finland. I live with my fiance, and my dog.

Im big into fishing, as well as car audio and electronics of all sorts. That’s my dog out on the boat, hes a cool dude, and loves to be in anybodys lap.

I started doing car audio work professionally at the end of high school, and went to college at Rensselaer Polytechnic, before going overseas to begin my military service. I am 26 now, I work as an organic chemist at Connecticut College, and still maintain my car audio career as well.

I served in the Finnish military and am an active U.N. reserve as a mobile light-mortar infantry soldier. When I began my military career I was told I should stick with military police, but as many of you could relate I fell in love with the mortar bass When I say I’ve heard some of the loudest/most ridiculously earth shaking bass in the world, it wasn’t in a car. Now what would a 120mm grenade register on the term lab?

Now that you know a bit about me, I will start my build log; the special thing about this build is that it lacks anything that special. I planned originally to put my gen 2 BtL in this build, but decided to wait on the N2 when I discovered it was being released. I had a MB Quart DSC2000.1 and 450.4 laying around, already had Infinity Kappa 6x9's rear with Infinity Gold 2.5" pillar and Rockford Power 6.5" Coaxials in the front doors. I decided it was time to drop something into this car, make me have some incentive not to trade it in for another Jeep or something. Knew I could get a few batteries in the trunk on a battery isolator to feed my power demands, the rest was just an issue of space. The equipment list checked out, now I knew I was in for some akward, tedious work, just because this car is particularly difficult to work on (who designed that battery compartment? i want to talk to that guy at chrysler seriously) and I had an ambition plan to make a big box and still have easy access to my full spare tire, and still be able to enjoy the way it looks and sounds. Its easy to do anything if your budget/resources are endless, but its hard if you have a tight budget and minimal fabricating equipment. All the work was done in my house (garage/driveway), no work while in the shop or even one bit of helps from a friend (arsehos, they just drink beer and watch ). As you will see, I built the box inside the trunk (mostly), using minimal tools besides a pair of cordless drills, a pair of jigsaws, and some squeeze clamps (and gorilla glue). Without counting the cost of equipment, total cost in wood, fiberglass resin/cloth, screws and glue was only around $250, most of which is some fancy thinned resin I bought down at industrial supply since it was around 45 degrees during most of my fiberglassing. The point I’m making is that you can create very stream-lined, potent sound systems with little cost and few tools, just a general confidence with your hands. Lets begin shall we?

It’s a deep trunk, almost 50 inches deep with 38” width at its narrowest.

This part is the problem; I only have just under 13” clearance… that’s not gonna do for what I have planned.

A quick shot of the 1/0 going to the trunk… I bought 50ft ground and wrapped the pos with blue tape since im cheeeeap. Also spot the 8 ga running to the center console.

Ran the 1/0 under the car and up under the rear seats. Caulked it like crazy later on (I get paranoid about water… a rusted ground caused by a little moisture cost me about $2500 in amps on another build).

Alt wire, some leftover dB link 1/0 cable I had… stiff as hell but nice and thick, did the trick.

This car has the most absurd battery location, with almost no space for my Orbital exide negative terminals to clear, let alone a battery clamp, so I found a slim profile terminal… looks naked in this picture tho

For anybody out there lookin for an easy tip, many will tell you that you can run big wire anywhere and even if it gets hot its no big deal, and though it would be hard to melt the wire without it resting directly against the engine block, the further you can get it from heat the better it will conduct. You wouldn’t believe the difference a couple degrees makes for voltage drop. Im not running crazy big power tho, but its still good practice.

This picture illustrates an important design aspect of this particular setup, in that the power wire split in the above distribution block enables me to run one amplifier off the primary (starting) battery and the battery compartment in the trunk is then isolated to run the monoblock off a separate charge, though obviously both the primary and auxiliary batteries are charged from the same alternator. More pics of that later.

Stinger gold ftw

Test fitting the power inverter, which is going to be mounted above a dual relay housing, which is what all those wires underneath the inverter run to. Another tip for you battery-loaded systems out there run both an accessory powered relay and an ignition powered relay for controlling certain system aspects via both triggers… makes things a lot easier.

Im a big fan of having an inverter in your car. You go two years not buying new cell phone chargers for your car and it pays for itself not to mention running music and a term lab off my laptops

Its really easy to just start cutting up pieces of wood, but I like to have a battle plan. Cut certain pieces in certain ways and you can end up with perfectly even cuts and exact symmetry.

See? Perfect.

Then theres the ‘clamp two pieces together and cut them at once’ trick

It’s the baffle mount, curved to add little fiberglass shunts since theres so few screws going into the wood in this build.

Test fit

Another angle

Bolted in some angle iron to run a straight line… it was later tacked into place right before I bolted the box to it from below.

Warning. Don’t try this at home

Last look at the box before it goes into the trunk for the rest of the build

Another fit test… Now its time for some gorilla glue and big clamps

Got a couple screws in there; gotta keep the ports nice and square.

Lots of gorilla glue and liquid nails… the screws I did put in (where I could fit a screwdriver or drill) end up negated by the fiberglass bracing, but extra never hurt.

And how is that a woofer box again?

Just had to push her in all the way, see how she lines up.

Its always good to keep planning and making to do lists; it really helps the build progress.

Heres what I have left to do at this point:

SolidWorks modeling all the way… really helps especially with the tuning process, and the wood cuts

Now for a couple weeks worth of fiberglassing since its so cold out it literally takes 48 hrs to cure sometimes. I buy more hardener than resin Its satisfying laying down a couple layers tho… really makes the box solid as a rock. Tip from a chemist: heat isnt the only thing to cure fiberglass. The catalyst is a peroxide like benzoyl peroxide can catalyze teflon to arrange itself into one long, hard molecule chain, but in this case just the catalytic energy is necessary. A good source? UV light... shine a UV light on that fiberglass and it takes off fast.

Fiberglass bracing 101: Double double layers on the corners with fewer screws, and plenty more glass to be added inside.

The fan doesn’t help the smell inside the car at all… just keeps me from passing out totally

A shot of the bracing on the back of the box. Its also where the amp rack will secure to, so it’s a vital piece.

Some more glass why not…

Not the perfect acoustic shape, but it thumps so hard who cares.

After the angle iron is tacked in, I needed to raise the box a half inch to flush it with the piece it was being bolted to. I didn’t get a picture, but theres four half inch mdf strips that the box sits on, keeps the moisture from collecting too. After its bolted in the box is officially mated to the car.

View from the drivers seat

Used the ‘angle the box so the resin pools’ trick and got four layers of glass in there to brace the baffle.

[SubSam 21]

And more glass

It just occurred to me I suck at taking pictures

Now theres some serious glass on the other side of the baffle as well. See the spots where I left the baffle mount curved how the resin can be built up and cloth sunken in to make little solid fiberglass shunts for braces… basically along with the screws theres fiberglass wedging it in from all sides. Its solid for a single layer baffle.

Time to fiberglass the box out of the trunk and build the amp rack.

Test fitting the amp housing size.

Of course I fiberglassed the whole rack without test fitting it, only to find out it didn’t fit no matter how I tried, so I cut in half and decided to build onto the right half by building the other half separately and joining them later on.

I like a heavy-duty felt like material for making certain molds that require strength. The felt really absorbs the resin well, two coats of resin with some scraps of fiberglass and sawdust in it and the felt becomes stiff as a board. A couple layers of cloth and resin over that and its good to go.

Amp rack progress

The deer had to come check out my rack drying out in the backyard. There were deer everywhere for a few days, including one bigass buck that sent me running inside like a little girl. Usually deer are scared as hell, this guy stared right at me and headed my way. I was outta there!

With the amp rack attached, I could begin making the skirt to flush the rack to the trunk. Again I used the felt and a few secret tricks to get the shape just right, and laid the resin down heavy.

More resin… amp rack makes a good beverage holder while its not housing the wattage.

Fiberglassing some cloth in there

Some more cloth… thing is hard as nails

I love dynaglass… its really a step where you can correct so many minor imperfections with one well performed sweep of the mud knife. You can build up areas and fill gaps way bigger than bondo, but it’s a real pain to sand down if you lay it on too thick.

Sand it down, fill it back up… x3

Same stuff

Some grey primer shows all the little lumps and divets you can fix with sanding/body filler, if you did a good job with the dynaglass this should all take about an hour tops. Then its on to carpet.

This is about the time I realized my spare tire needed about a quarter inch more clearance to get in and out easily, so I had to halt progress on the trunk until I feel I can shave down the bottom of the rack and put down some more dynaglass and finish the bottom portion of the carpeting. The false floor will be easy enough to build.

So earlier I mentioned the battery isolator. By mounting it in the trunk, inside the battery chamber, and wiring the 4ch to the T-Distro ’above’ it, the isolator keeps the auxiliary and primary batteries separately but adequately charged and the amps are fed by two different charge sources.

Time to close up the battery compartment

Lots of wires ran, the amps are going into their pre-bolted positions on half inch MDF mounts. This allows me to run some RCAs and other wires beneath the amps, while also giving the amps some more breathing room.

So flush and so clean.

Some aluminum battery terminals I cut out in a jiffy. Triangles hot and round for ground. You can get more conductivity from copper or brass, but these will do. Long as theyre smooth.

Building out the battery door.

Now that’s the shape

Close

Gets a little repetitive… but its worth it to get a flush fit

After a quick check on the collective battery/alternator performance, I wired up the relay and powered up the amps.

Wires did a vanishing act.

----THEN I WAITED… sat around for a long time with nothing personal to work on, but built up some car audio business in the meantime. In the back of my mind Im just thinking BtL, BtL, BtL... I really wish I held onto my gen 2, or one of my spare Fi Q's, but its ok I still had my other vehicles to bump around in.

Then on Monday the UPS guy gave me a nice surprise

[SubSam 21]

I was pretty damn excited to wire it up… A big hell yes goes out to Fi Car Audio for making great woofers including this new BtL, I know it was a pain to make this sub for me, but I appreciate it. Then five minutes later:

The most anxious part in the build… I had measured the side-to-side distance to be just capable of clearing the woofer. Lets just say a piece of paper can slide in on one side but not the other Been waiting to predrill the woofer mounting holes so I can carpet the visible portions of this side.

The fact that the baffle was so closely measured side-to-side meant the woofer was automatically lined up in that regard. I cut the mounting hole exactly so that the outer edge of the woofer would be a half inch off the floor of the trunk, so once I shimmed the woofer up with a piece of .5” MDF it was just about lifting the magnet into place with some lumber I had laying around, which in turn brought the woofer flush. I did a poor job leveling the magnet, I guess its hard while looking upside down and backwards at it but its fine. The hole was cut 14 and 3/16 inches, and the woofer sits in there perfectly inverted. With that magnet, how can I not invert it??

You may have seen this picture already, but that’s the only one I snapped before I put the back seat in. I have a few things to tweak in there in the coming weeks, so I will probably wire that up in a prettier fashion. Honestly the woofer has itty bitty clamp terminals, real tough to get full copper contact with one 8ga input let alone two. Its in, its tight, im not touching it for now

Putting my back seat in was a real pain… Its so closely fitted again that the back of the seat actually flexes a bit against the box when I bolt it down, but I wanted that so the seat sits in place tightly and doesn’t get pummeled around by the BtL. I used some adhesive rubber strips, big chunks of closed cell foam, and some carpeted pieces of MDF to keep an airtight seal between the woofer’s “chamber” and the seat. I doubt the seat is rigid enough to allow for a 6th order effect from the seat blow through, but who knows.

I don’t live in the most crime filled area, but around here if somebody peeked in and saw a monster 15” BtL they would probably steal my car. The woofer was bolted in with Torx screws and my father-in-laws 50lb torque drill, into a half inch of fiberglass. Nobody could budge those screws with any cordless drill, let alone a screw driver

And that’s how it has to stay for now, at least until after xmas. I left enough room for mounting a second monoblock, I hope to upgrade to a pair of Rockford bdCPs. The box sounds good so far as it should, very much a similar overall design scheme compared to my previous BtL enclosure (visible next to my name over there <<<<), time will tell if it really bangs like the gen 2. Door panels are also soon to come, though my highs are well suited to the current configuration, I just want a little more flare than the stealth look this car has now.

Thanks for reading, feel free to post comments. Enjoy your holidays, relax like my dog here, just toasting in front of the wood stove

[xAndrew225x 8]

Awesome build man! I love the inverted look and box design.

Great job dude keep it up

[Mac N Cheese 90]

I love the position of the BTL. Nothing like seeing the motor through the ski hole

[Shogen 325]

Looks great!!!!!

[heckvr4 2]

looks like a lot of work...

very nice...

[Kanaworm$ 292]

Welcome ....

Great job on the install!

Love the pics of the northern pike and the pooch!

[TRP 42]

Lots of great work man!! And i completely understand what you are saying about the mortar bass!! I had several drop around me when i was in Afghan and man those things have some punch behind them!!

BTW in the first picture i thought that was your 11 year old son!!! HAHA!!

[bcst86 5]

looks nice. great job man

[aimone 4]

real nice work man.........also are those punch hx2 12's in the second pic and the pic comparin it to the btl? ive got a power hx2 15 and i love it its currently only runnin on 1 coil on my saz-1500 cuz i killed the other coil. hopefully next pay day or the one after im gettin a recone with upgraded coil n soft parts.

[Notorious97200 339]

I did not really understand your box !!! :roflmao:But if it sounds good and you like it : it's cool !

Great work.

[j-roadtatts 1,129]

Awesome job on the whole build SubSam! Your planning and patience shows through on the finished product. That FI sub is gorgeous, definetly worthy of showing off that crazy lookin ass. Good job on keeping the spare also!

[SubSam 21]

thanks to all for the nice words! @TRP yea I look super young... I still get carded for cigarettes and ill get carded for beer probably till im 40 lol

@aimone yea its a punch hx2 im a big fan of the hx2s, both punch and power. Ive been installing them for a decade or more, still have a half dozen 12s laying around. I think I will go lay them out and lay in the middle and flap my arms untill I make a woofer angel lol

Its christmas eve after all lol

[Bob345 39]

Looks great!! And solid works ftw!! I use it for every thing. Very powerful software

[dorian01 0]

if you made the neo magnets vertical instead of horizontal the ports would blow air right on the heat sinks.

awsome box

[aimone 4]

thats awesome man..... i wish i could find more HX2's but there kinda hard to find in great shape and at a good price. if you werent located in finland id try everthing to buy a cpl of them from ya lol, but shipping and customs would probably be a bitch and cost an arm and a leg

[SubSam 21]

Looks great!! And solid works ftw!! I use it for every thing. Very powerful software

I too use it for everything! I will redesign a box like 100 times on solidworks until I get it just right... The software really makes all design processes so fast and time efficient (if ur good at it), and it is an awesome skill to put on your resume. Everyone needs a CAD tech

[SubSam 21]

thats awesome man..... i wish i could find more HX2's but there kinda hard to find in great shape and at a good price. if you werent located in finland id try everthing to buy a cpl of them from ya lol, but shipping and customs would probably be a bitch and cost an arm and a leg

Actually im in CT just a finnish citizen with a green card, but the power hx2 is sold already, I just have to finish the install in my friends civic. Three of the remaining four punch hx2s are going into a single and double woofer install, all three are still brand new in the box. I have one more, and one coming out of my fiances old jeep liberty be replaced by a Fi Q, so I have two up for grabs. I know the one I have out now has 2.1 ohm dvc still, ive really babied it, the other I dont know for sure. If you or anyone else wants a rockin punch hx2 (rfd2112) send me a pm we can work something out I would love to see these woofers in a good home

[sefugi 166]

Great introduction!!! Great pics of the install, and nice work on the fitting of the amp rack!! Love the clean look of the trunk with the panels completed!!

[edouble101 314]

Nice box build

[SubSam 21]

Thanks all for the compliments and friend requests. About the pm regarding the wire covers, i did have better pictures of the sides:

They are made from quarter inch mdf and fitted onto a small central pin. The fit is so tight i could have pressure fitted them, but they would likely fall out when the BtL gets going...

Cheers and good luck with your install. Mimicry is the best form of flattery, im glad to help.

[SubSam 21]

So I have the results of the back seat test, which I suppose I should have predicted:

With the gains set where I want them and the volume mostly as loud as I would turn it up at this point (@28 on alpine cda-105) , its putting up a 145.3 on a 30Hz sine with the back seat off, 145.8 at 70 Hz, and 146.9 at 35Hz. I put the seat back on, and metered about the same (both down .2dB) at 30 and 35, but 144.6 at 70 Hz.

Other data I took (back seat off/on): 25Hz (139.4/138.5), 40Hz (145.8/145.8), 50Hz (145.4/145.1), 70Hz (145.8/144.6), 80Hz (143.1/143.0), and 90Hz (135.9/135.4). Basically it all went down (seats not stiff enough) and was way down at higher freq (same at 40, -1.2 at 70). It's not a huge difference, but I'm hoping for a gain. Key word: hoping.

I have a strong recollection of a 146 number with my gen 2 at 30Hz and 144s at 50Hz, but in my grand prix on a different amp and the box was definitely tuned lower. Hard to compare, I would be really stretched to say anything in terms of a comparison; they are both awesome woofers. I have an inkling that my negative 6th order effect is due to the woofer being inverted and consuming volume in that mounting location. My project for tonight is to take it out, flip it around, and then meter it again tomorrow, hopefully with dB's on the plus side. If not, oh well, I'm not really expecting it to work lol.

Anyways that's the fun I've been having. More soon, maybe even pictures of it non inverted

Edited January 6, 2011 by SubSam

[onebadmonte 235]

Nice install, and impressive scores for a single twelve. I'll definitely be picking up an N2 for my ride.

[SubSam 21]

Well I got it in non-inverted... I really wish I left myself more clearance to get it in there, it really is difficult to maneuver a 40+ lb woofer little by little with your fingers Theres 13" of clearance and a 15" woofer in there for petes sake!

Anyways on to the pics:

See how I left myself a dandy ol' problem?

But there she is, after a monster of a struggle... Now I can watch her dance for me

And just to make sure nothing came loose during the flip it is good practice to check your connections beforehand:

Thats still a .8 across the voice coils... fresh as a daisie

Ill keep ya'll posted on the meter runs tomorrow