Help me spec out 2 car sub boxes

[EndersShadow]

So I am debating building my own boxes for the sub in my car. The goal is to build 2 boxes that will be side by side that are front firing, and front ported (below the sub). I am looking for 2 boxes so that they can be somewhat modular so I can use at least one side of the trunk in my Jetta if needed for storage. The subs I am using will be 2 Treo TE 10.44 4ohm DVC?s (spec?s here). I own one already so I can easily just purchase another. They will be powered by a Sundown 1200D (spec's here) which can provide 1200 watts x1 @ 1 ohm so I am good with power.

The plan is to bi-wire the 2 boxes at the amp so I am providing that 1 ohm load to give each sub ~600 watts. Since the max wattage for each sub is listed at 500 watts I would have to keep the gain down a little bit, but not much. Both boxes will sit side by side with a little bit of a gap inbetween (I envision but am not 100%)

I am hoping to figure out a way that will allow me to disconnect 1 sub easily & quickly so I can move the box to sit in front of the first one in a quick pinch or remove it entirely. I am going to leave myself enough wire so that I can sit them in front of each other while still able to play both. I was figuring on using bananna plugs on the sub box end just to make life easy for disconnection purposes. Am open to other wiring suggestions.


I am looking to know a couple things, and maybe get a couple tips.

1. Whats the average lowest hz frequency most music has. I figured I would tune the box (since I am going ported) to a little bit below that frequency.
2. What thickness of MDF/Plywood should I use? I plan to use screws in addition to a bunch of wood glue and then silicone the seams. Then cover the entire outside of box with rhinoliner (like the brand Pro-Box does) and possibly the port.
3. What programs do you guys use to help you build/spec them out with?
4. Anything else I haven?t covered yet lol?.

P.S. My uncles are carpenters so more than likely I would have them build the boxes for me and then I would pick them up and spray them myself.

[EndersShadow]

bump on day 1

[Drenis]

I really don't like the design of 1 amp running 1-ohm pushing 2 woofers... Here's a link how to wire it for a 1-ohm or 4-ohm load. Might give you some direction how to plan your boxes considering the wiring.

http://www.rockfordfosgate.com/rftec...2&woofer_imp=4

You mentioned a Jetta... hatch or sedan? Would it be possible to consider fibreglassing a single sub in each corner of your trunk (if a sedan)? This would leave all the center of your trunk open even with seats down.

[EndersShadow]

I really don't like the design of 1 amp running 1-ohm pushing 2 woofers...

Thats my only option for my sub amp. This brand is a Car Audio Competition company so I have no doubts its capable of 1ohm loads. The guys I bought it from are running tons of these with those loads.

You mentioned a Jetta... hatch or sedan? Would it be possible to consider fibreglassing a single sub in each corner of your trunk (if a sedan)? This would leave all the center of your trunk open even with seats down.

Can't do anything in the corners. Thats where my crossovers for the db6501's are housed, as well as the distribution blocks for my amps and the grounds. In addition I wouldnt be able to get to my blinkers to change out bulbs due to the depth I would need. It was something I did consider though.

Plus anyway you look at it, I still have to mount the amps somewhere. Currently they are both mounted on the 60 side of my 60/40 split backseat. I dont plan on making this any deeper than my current box (which is 1/2 the depth of my trunk right now) and probably shorter since I plan to go taller than I am right now, so I technically will be reclaiming space anyway.

[EndersShadow]

My current sub box is here. Its W: 20" D: 14.75" H: 11" with an airspace of 1.20 cu. ft.

I only need to go ~7 inches deep if there is nothing behind the sub as the sub is 6" deep. While the enclosure is only 11 inches tall I think I could go another 3 or 4 inches there and then cut that from the width (and possibly depth).

[dcmartinpc]

I will see if I can model something up this weekend or early next week. I would do it sooner, but I am going in for a tonsillectomy tomorrow morning! I think I should be able to come up with something pretty nice. Out of curiosity, what tuning are you looking for? I will try to find the best tuning for those subs to make them shine the best, but I din't know if you had something in mind.

Don

[EndersShadow]

I will see if I can model something up this weekend or early next week. I would do it sooner, but I am going in for a tonsillectomy tomorrow morning! I think I should be able to come up with something pretty nice. Out of curiosity, what tuning are you looking for? I will try to find the best tuning for those subs to make them shine the best, but I din't know if you had something in mind.

Don

The subs frequency response goes down to 25 hz it looks like. Personally I think that is probably low enough for most music, but if its possible to get it lower that would rock.

I know most music doesnt go that low and with doing 2 subs with that amount of power I should get a lot of chest pounding bass at 25 hz.

I am basically open to suggestions, just looking to maximize my setup and really "feel" the bass but I dont want it bloated or loose...

[Drenis]

Thats my only option for my sub amp. This brand is a Car Audio Competition company so I have no doubts its capable of 1ohm loads. The guys I bought it from are running tons of these with those loads.

To be honest I have never heard of this company nor do I have any personal experience with them. But I try to keep up in the industry on most high end brands. I personally run RE Audio & US Amps equipment in my car.

Can't do anything in the corners. Thats where my crossovers for the db6501's are housed, as well as the distribution blocks for my amps and the grounds. In addition I wouldnt be able to get to my blinkers to change out bulbs due to the depth I would need. It was something I did consider though.

You have your crossovers for your front mounted in the trunk?? Strange... even not recommended by most pros. Usually you want crossovers to be as close to the speakers as possible within reason.

Assuming you DO in fact have a sedan Jetta, you could 'glass enclosures in the corners that CAN be removed. I'm currently doing a corner enclosure for my girlfriends Tiburon while mounting the amp on the same side panel wall that runs up the length of the rear strut. Could you build a fake wall on the side or above your wheel wells to mount and manage cable distribution?

I'm very certain you could make something work and be efficient with a custom application. Just have to plan it out.

My current sub box is...

Prefab... in the car audio community, you'll never reach a drivers potential with a prefab'd box. Never. They sell a lot of Bassworx products that make noise but are just generic designs.

Box design is EVERYTHING. Just building a box to spec for your driver will do it wonder. This is in addition to the tune of the box.

The subs frequency response goes down to 25 hz it looks like. Personally I think that is probably low enough for most music, but if its possible to get it lower that would rock.

I know most music doesnt go that low and with doing 2 subs with that amount of power I should get a lot of chest pounding bass at 25 hz.

I am basically open to suggestions, just looking to maximize my setup and really "feel" the bass but I dont want it bloated or loose...

Tuning is all relevant to the driver choice. If you look at the specs for your driver, you'll see the manufacturer has recommended figures for both sealed and ported applications.

I run a single 12" in a tuned ported box. And it's MORE than I need.

[EndersShadow]

To be honest I have never heard of this company nor do I have any personal experience with them. But I try to keep up in the industry on most high end brands. I personally run RE Audio & US Amps equipment in my car.

I am familiar with both those brands. Treo is quite good given its price and its something the shop I got most of my gear at is very familiar with. They recommend it over JL and many other BB products. I have been running mine for 4 years with no problem at all.

With Car audio there are a massive amount of brands that I have never heard of because I am not as into that as I once was.

Just like I didnt know who SVS was for HT subs until I joined a couple forums.

You have your crossovers for your front mounted in the trunk?? Strange... even not recommended by most pros. Usually you want crossovers to be as close to the speakers as possible within reason.

Yes, the door panels on a Jetta leave very little room for anything. They actually install a large piece of foam that fills in the void around the speaker and a couple inches to either side. Then factor in a layer of Dynamat Extreme on all 4 doors and the fact the amps (where the speakers get their power from) are mounted in the trunk and it was easier to run 2 sets of wire from the trunk to the doors and put the crossovers in the trunk, than find a way to mount the crossover in the door panel or on the floor of the Jetta.

Could you build a fake wall on the side or above your wheel wells to mount and manage cable distribution?

I'm very certain you could make something work and be efficient with a custom application. Just have to plan it out.

Most of the cables run on the bottom of the floor of the trunk and are not seen at all. I will try to take some pics later to show better what I am talking about.

I am trying to not build something massive and I also have to be able to access my spare which would be a problem if I built something along the side wall.

I am also trying to NOT make this something that once my Jetta goes I cannot reuse.

Assuming you DO in fact have a sedan Jetta, you could 'glass enclosures in the corners that CAN be removed. I'm currently doing a corner enclosure for my girlfriends Tiburon while mounting the amp on the same side panel wall that runs up the length of the rear strut.

Prefab... in the car audio community, you'll never reach a drivers potential with a prefab'd box. Never. They sell a lot of Bassworx products that make noise but are just generic designs.

Box design is EVERYTHING. Just building a box to spec for your driver will do it wonder. This is in addition to the tune of the box.

Tuning is all relevant to the driver choice. If you look at the specs for your driver, you'll see the manufacturer has recommended figures for both sealed and ported applications.

I run a single 12" in a tuned ported box. And it's MORE than I need.

Fiberglass is a bit more than I want to get into at this point. Plus if its fiberglassed normally its not going to work in another car. The Jetta is a 00 with 165k on it so I dont have more than maybe 3 years on it. As such I cant justify the cost and time/effort of fiberglassing a box.

The box I have while pre-fab is actually much better than most boxes I have used/installed. It is a perfect fit for me right now, I just cant put 2 of them in the car and figured I would try my hand at designing one since I could have it built by someone with some good wood skills.

I have looked at the spec's for my driver but I am not familiar with what means what in them, hence me asking here.

[Drenis]

Yes... given that there are so many brands it's difficult to keep up. None of that mainstream sony crap in my ride...

I've seen people mount crossovers under or behind the dash (glove compartment?) and even under the seats when space was an issue. I know I myself will have fun when it comes time to install my RE XXX component crossovers.

Definitely looking forward to seeing pictures. I'd love to offer any suggestions I can but it's hard sight unseen.

And your last point about fiberglassing, I completely understand. I only recommend it as it can be a permanent or semi permanent solution that CAN accommodate and efficiently utilize space. It sounds like you would benefit from a proper built box that CAN be removed and reused.

If space is a issue for a box, I would look to a sealed enclosure. I also recommend doing 1 single box over 2 smaller ones. But that's my preference. Have your uncles ever built a box like this before? Don't skimp on materials.

[EndersShadow]

If space is a issue for a box, I would look to a sealed enclosure. I also recommend doing 1 single box over 2 smaller ones. But that's my preference. Have your uncles ever built a box like this before? Don't skimp on materials.

Space isnt too much of an issue since I normally dont have anything in the trunk. But since I did just finally get back the 40 part of my trunk (I got new amps that both fit on the 60 side) I would like to be able to move/pull one out for trips with the wife, etc.

That way I can at least fold down ONE part of my backseat to store long items (like floorstanding speakers )

90% of the time both boxes would be in place, but having a modular design so I can pull/move one out of the way if needed would be very much prefered, and is the entire design goal of this project.

One of my uncles who is a carpenter is a big audio nut runs his own custom DJ setup for my cousin to sing at venues, and has a ridiculously loud HT setup. So while he hasnt built a box before, he's got an entire shed of tools to do so (routers, table saw, bandsaw, etc). If I get him the spec's and materials and some blueprints he's fine. He was a Project Manager/Foreman for a construction company.

He also has a bunch of crown amps to test things out before we would get it all installed to ensure it works

[EndersShadow]

Attached are some pics of the install. Note the driver side crossovers are entirely hidden within that compartment. Only the passenger side crossovers are visible, and even then not that bad considering.

As you can see I have a bit of space vertically that isnt getting used, so I am hoping to use that and use less depth. Also since I want the port to be underneath the woofer that will use up some space as well. Currently the port is off to the drivers side.

Also note I have the rears disconnected as I blew a crossover on the passenger rear and then went to a 2 channel amp. I could technically get a new crossover (32 + shipping from Polk) and run both sets off the amp (since its 200x2 @ 2 ohm) but I dont see the point currently.

The last pic is with the seat down showing some of the wiring. Someday I will clean it all up again, but for right now its fine

**edit** I can take more if needed, but the camera died after my last pic lol

[VR3]

1. Whats the average lowest hz frequency most music has. I figured I would tune the box (since I am going ported) to a little bit below that frequency.

30hz and up
2. What thickness of MDF/Plywood should I use? I plan to use screws in addition to a bunch of wood glue and then silicone the seams. Then cover the entire outside of box with rhinoliner (like the brand Pro-Box does) and possibly the port.
3/4 inch is fine - 1.5" for the baffle.
3. What programs do you guys use to help you build/spec them out with? Winisd is pretty good for most things
4. Anything else I haven?t covered yet lol?.

I would design it to where you are running the other sub parallel so you can just disconnect it at anytime...

[VR3]

You could also maybe run a second amp for the sub that way when you disconnect the second one it wont change the ohm load. Just a thought

[EndersShadow]

1. 30hz and up
2. 3/4 inch is fine - 1.5" for the baffle.
3. Winisd is pretty good for most things
4. I would design it to where you are running the other sub parallel so you can just disconnect it at anytime...

You could also maybe run a second amp for the sub that way when you disconnect the second one it wont change the ohm load. Just a thought

1. Good to know since the sub lowest frequency response looks to be 25hz. So I should be covered.

2. Would it be bad to go with 1" and cost a bunch more? Also what are your thoughts about flush mounting the woofer?

3. Winisd doesnt look to work with Win7 which is all I got at home

4. I was planning on running them in parallel as another amp is going to cost me 400+ since I would stay with Sundown. That and also a thicker gauge of wire (I have 4 gauge but would need 1 or 0) for both power and ground.

Thinking about wiring, how should I work that one out? Basically bi-wire from the amp, or wire sub 1 direct and then have sub 2 connect to sub 1?

[VR3]

I use Winisd with Win 7 all the time! :)

Just do 3/4 with some bracing - double up on the baffle and recess the woofer to make it look pro.

I would just have sub 1 connect to sub 2.

[EndersShadow]

I use Winisd with Win 7 all the time! :)

Just do 3/4 with some bracing - double up on the baffle and recess the woofer to make it look pro.

I would just have sub 1 connect to sub 2.

Cool, will have to play with it this weekend then while the wife it out and about.

See what I can come up with.

Just wondering if I want an angle on the front, or just straight square......

[dcmartinpc]

I use Winisd with Win 7 all the time! :)

Just do 3/4 with some bracing - double up on the baffle and recess the woofer to make it look pro.

I would just have sub 1 connect to sub 2.

Sub to sub is what is was thinking too. If you want to be really cool and make it crazy easy to swap out, you could use speakon connectors on the subs. Twist, lock, and done. Reverse to remove. Just a thought. Nice and clean, secure, and avoids bare wire.....

Don

[EndersShadow]

Sub to sub is what is was thinking too. If you want to be really cool and make it crazy easy to swap out, you could use speakon connectors on the subs. Twist, lock, and done. Reverse to remove. Just a thought. Nice and clean, secure, and avoids bare wire.....

Don

I was thinking about using something like this that allows bananna plugs or spades. I got a bunch of Monster quick connects at home I could use along w/ Monoprice wire....

Unless I felt like going crazy and using some Audioquest wire, which I am debating using to wire it internally lol....

I would still need to find some type of fastener to keep the boxes from moving around. My current box slides side to side. I debated getting some velcro tomorrow and just using that lol...

[VR3]

I vote velcro

[cheezeitz51]

Just tune it around 30hz and use 3/4" mdf and double it up on the front and use win isd to model the box.

[EndersShadow]

So I just installed Winsd and gotta admit, I have NO FRIGGIN CLUE how to work this program lol.

I attempted to fill in all the spec's for my sub from the manufacture site but either they all werent there, or I didnt know which ones were which lol....

Hoping someone here might be able to help me out by maybe getting some drawings together.

I am going to try and get measurements of my trunk space here tonight or tomorrow lol.

[EndersShadow]

So talking to a bunch of folks I think going with one massive sub is where I am going to go.

Some generic measurements of my trunk are 39" W x 20" H (this is the lowest point where the seat dips down so I technically have more) x 25 D. My current box is 20" W x 14.5" D x 11" H. Its got 7 inches before I couldnt pull it out the back seat if I wanted. So I wanted to attempt to reclaim some of those 7 extra inches for the new box, and make it a little bit slimmer while not killing its depth.

I am looking at the TC Sounds LMS-R 12 as it can handle 1000 watts RMS w/ 2000 watts peak. Its a dual 2 ohm sub so I can wire it to be a 1 ohm load on my amp. My Sundown 1200D maxes out at 1200 watts @ 1 ohm so its a pretty decent match overall.

Looking at the box I talked to some folks and it was suggested I should put in a 3 cubic foot sealed box which should get down to 30hz no problem.

Doing some basic math interior box dimensions would be 20 W x 16 D x 17 H which is ~3.1 cubic feet. The extra .1 allows me to put in some bracing of some sort. Final exterior dimensions would be 21 W x 17 D x 18 H to account for 1" thick wood. If I would probably need more than 1" thick wood please let me know. I may modify the box a bit so its angled on the back so I can use those couple extra inches at the bottom but I am not sure. I need to make sure my amps have enough room to breath

Also according to some advice porting this would be too much of a PITA. I was wondering if adding a 12" passive woofer (either on the backside of the box, or on the top) would be worth it or not?

[dcmartinpc]

So talking to a bunch of folks I think going with one massive sub is where I am going to go.

Some generic measurements of my trunk are 39" W x 20" H (this is the lowest point where the seat dips down so I technically have more) x 25 D. My current box is 20" W x 14.5" D x 11" H. Its got 7 inches before I couldnt pull it out the back seat if I wanted. So I wanted to attempt to reclaim some of those 7 extra inches for the new box, and make it a little bit slimmer while not killing its depth.

I am looking at the TC Sounds LMS-R 12 as it can handle 1000 watts RMS w/ 2000 watts peak. Its a dual 2 ohm sub so I can wire it to be a 1 ohm load on my amp. My Sundown 1200D maxes out at 1200 watts @ 1 ohm so its a pretty decent match overall.

Looking at the box I talked to some folks and it was suggested I should put in a 3 cubic foot sealed box which should get down to 30hz no problem.

Doing some basic math interior box dimensions would be 20 W x 16 D x 17 H which is ~3.1 cubic feet. The extra .1 allows me to put in some bracing of some sort. Final exterior dimensions would be 21 W x 17 D x 18 H to account for 1" thick wood. If I would probably need more than 1" thick wood please let me know. I may modify the box a bit so its angled on the back so I can use those couple extra inches at the bottom but I am not sure. I need to make sure my amps have enough room to breath

Also according to some advice porting this would be too much of a PITA. I was wondering if adding a 12" passive woofer (either on the backside of the box, or on the top) would be worth it or not?

The external dimensions would actually be 22 W x 18 D x 19 H as you have 1" on either side I do that all the time. You have to count the 1" twice.

With passives, you would really need 2 or a single larger passive, say an 18". The nice thing about dual passives is that they cancel each other out if you mount them opposite each other and keeps the box from jumping around. You would definitely gain output down low at tuning with dual 12" passives, that is for sure. If you do go with passives, I would stick with the TC Sounds passives.

If you can fit it, I personally think you would be happier with a 15" LMS-R.

Don

[EndersShadow]

The external dimensions would actually be 22 W x 18 D x 19 H as you have 1" on either side I do that all the time. You have to count the 1" twice.

DOH! Well gotta tweak the box as thats a little bit too big for what I want.

Would I need 1" thick MDF for this or could I get by with 3/4".

With passives, you would really need 2 or a single larger passive, say an 18". The nice thing about dual passives is that they cancel each other out if you mount them opposite each other and keeps the box from jumping around. You would definitely gain output down low at tuning with dual 12" passives, that is for sure. If you do go with passives, I would stick with the TC Sounds passives.

Yeah, 2 passive 12's are a bit more than I was looking at, so debating adding them at all. Realistically may not need the output down low. Will do some WinSD modeling tonight to see whats what.

If you can fit it, I personally think you would be happier with a 15" LMS-R.

I have the room for it in that box, just trying to keep costs low.

[EndersShadow]

Ok, revised dimensions:

Interior: 19 W x 16.5 D x 17 H
Exterior: 21 W x 18.5 D x 19 H

Just need to check if I could still get the sub out of the trunk if needed, as well as the spare lol......

Will probably build a cardboard box template box this weekend to test it out....

[dcmartinpc]

For the 12" I would think 3/4" would be fine. If you were planning a possible upgrade to the 15" sometime in the future, then I would go with 1" just to be safe. The box should work for both, you could just cut the whole larger later.

I think even sealed, that you will be very happy with the performance of that sub. Running them sealed they are SO clean!

Don

[EndersShadow]

For the 12" I would think 3/4" would be fine. If you were planning a possible upgrade to the 15" sometime in the future, then I would go with 1" just to be safe. The box should work for both, you could just cut the whole larger later.

Yeah, I think I will stick with 1" just so I have options. Going to mess with the box dimensions in WinSD tonight when I get home and maybe mock up a template on Sunday while the wife is at work.

I think even sealed, that you will be very happy with the performance of that sub. Running them sealed they are SO clean!

that sub being the 12" TC Sounds one right?

[EndersShadow]

Was bored at work so decided to see if we had the stuff to make a mockup. We did but man is cutting corrugated cardboard a PITA.

Have all 4 sides cut and will be taping together and post pics after work tonight.

One thing I can say, this box is friggin ridiculously big...

[EndersShadow]

Ok, so I saw this box below and it gave me an idea and a question.

Question: Does it matter the orientation of the sub within the trunk (i.e. does it need to be facing back, front, sideways, etc.





If it doesnt matter how the sub is mounted, I could do something similar using the rear passenger side of my car, as originally mentioned by Drenis.

I wouldnt do anything fancy with fiberglass, but I could run it the full length of the trunk (23 inches internally volume), the full height (18 inches internally on one end, 23 on the other), and then make it as shallow as possible (~11 inches internally). I would also use the current trunk floormat as a template and build a double hinged access to the spare tire.

A box as long as that would allow me to take my wiring and put it all on one side, and hide it in a box similar to what the pictures above have on the floor.

I would then get back a bunch more trunk space.

BUT this is all assuming orientation of the sub doesnt matter.....