Gauging Interest: Rear Custom-fit Sub Box

[Gridikal]

http://www.bcae1.com/

has a bunch of different formulas and ideas that can be very helpful when desigining enclosures as well as alot of other very good 12v electronics info.

Polyfill does actually work, not exactly sure how, but it does. I know theres some science behind it, but if a box is too small, adding some polyfill does help...an educated ear can easily hear the difference, but definately you want the enclosure to be as close as possible, only using the polyfill to "fine tune" so to speak ie: don't build a .65 enclosure when your sub needs 2 cubes and just stuff the hell out of the .65.

The sound waves get bent around the strands in the polyfill- slowing the waves down.

If you plan to use polyfill (or fiberglass insulation), it always is a good idea to make the box slightly small in volume so when you add polyfill it will make up for the slight lack in volume. (i.e. if 1 cu. ft. is required, and the subs displacement is say .25 cu. ft.- you would built the box to 1.15 cu. ft. which would give you a volume of .90 cu. ft.)
Polyfill is generaly required in sealed boxes as they tend to generate more high frequency resonance than say ported boxes- also you can use a tar-based spray to get the same effect without having to reduce the enclosure volume.

 

[Drake00XJ]

This thread got a little off topic. Are we going to be seeing these things produced on a by order basis?

 

[BoXJer]

This thread got a little off topic. Are we going to be seeing these things produced on a by order basis?

The thread is about rear custom-fit sub boxes... how'd we go off topic, we're talking about how they are made...

Anyway, just finished mine this weekend and will post pics when the big game is over. All I have to say is that it was A LOT of work and for anyone interested in this type of enclosure, pay a couple hundred bucks to have dothedew make it. It will be worth it.

 

[Gridikal]

Are we going to be seeing these things produced on a by order basis?

I will probley make one of my own design to begin with. Then, take detailed pics to show mounting, size, and just give a general idea of it. Then I'll open it up to whoever is interested.

 

[Drake00XJ]

Okay, I'll be waiting. PM me when you have all of that done.
Thanks.

 

[BoXJer]

Just finished it and posted some pics. Dothedew, I hope this helps sell your idea, cuz it would totally be worth it. I mean it was fun to do, but it was a pain in the A$$. I dunno if mine will hold up forever, but it sounds great and from what I can tell, there are no air leaks. Haven't measured volume yet, I think it's a bit big...

Anyway, heres the link to the pics:http://www.chalacha.com/chadsjeep/jeep.html

 

[Rand McNally]

Just finished it and posted some pics. Dothedew, I hope this helps sell your idea, cuz it would totally be worth it. I mean it was fun to do, but it was a pain in the A$$. I dunno if mine will hold up forever, but it sounds great and from what I can tell, there are no air leaks. Haven't measured volume yet, I think it's a bit big...

Anyway, heres the link to the pics:http://www.chalacha.com/chadsjeep/jeep.html

DAMN NICE!! You did a very nice job. Thanks for the write up also. What is the cubic size of this box? Again...looks way cool! I was thinking about building a box that looks like the spare tire. But this one really has me thinking. With this one I could keep my spare inside and still have a sub.

 

[BoXJer]

DAMN NICE!! You did a very nice job. Thanks for the write up also. What is the cubic size of this box? Again...looks way cool! I was thinking about building a box that looks like the spare tire. But this one really has me thinking. With this one I could keep my spare inside and still have a sub.

Thanks.

Dunno the volume yet. I'm guessing it's a bit bigger than I wanted. I wanted about .65 but I think it's about .85, which is still kind of in my range of "acceptability". If it turns out to be too big I'll fasten a 2x4 in the bottom of the box to reduce to interior volume. I was aslo considering using the spray foam to reduce volume, but I'm unsure if that will affect the acoustic integrity of the enclosure.

I still have my spare inside too!

 

[Rand McNally]

Thanks.

Dunno the volume yet. I'm guessing it's a bit bigger than I wanted. I wanted about .65 but I think it's about .85, which is still kind of in my range of "acceptability". If it turns out to be too big I'll fasten a 2x4 in the bottom of the box to reduce to interior volume. I was aslo considering using the spray foam to reduce volume, but I'm unsure if that will affect the acoustic integrity of the enclosure.

I still have my spare inside too!

How is it held to the interior wall? I wouldn't want that thing flying around in there...

 

[BoXJer]

How is it held to the interior wall? I wouldn't want that thing flying around in there...

It's just held in by virtue of the shape itself (almost like an airtight seal - it has no space to move). It takes some effort to pull it out. I was planning on using industrial velcro or a single bolt into the wheelwell, but I think that'll be uneccessary.

 

[Rand McNally]

It's just held in by virtue of the shape itself (almost like an airtight seal - it has no space to move). It takes some effort to pull it out. I was planning on using industrial velcro or a single bolt into the wheelwell, but I think that'll be uneccessary.

Personally, I would figure out a way to hard mount it in there. That way even if someone breaks in they can take it. In my Wrangler I had my sub box bolted to the floor with all the amps, CD changer, caps and what-have-you under the seat. The rear seat was chained and locked down so there was no way of getting under the seat or moving the box. They could get in, but they couldn't take anything. I am going to rig up a similar thing to the Cherokee, but my idea needs some fine tuning. Basically it will hold the rear seat from moving with a lock. Again, they can break in, but the can't take anything. Again, it looks great. I will be sure to post when I finally get my Jeep done. Slowly but surely things are coming together...

 

[xjfrank]

Can you make one for each side?

 

[BoXJer]

Can you make one for each side?

Do you have a spare on the driver's side??? Cuz I had plans to make an enclosure for an 8" sub WITH the spare. It was gonna go between the spare and the back seat. Just enough room for an 8" sub in a .5 enclosure. If you want a larger sub and box, I'm sure you could make it work.

Personally, I would figure out a way to hard mount it in there.

I certainly will figure out a way to do it, but it isn't going to fly around back there unless I take a roll.

 

[xjfrank]

No spare will fit there for me. But if you could make matching enclosures for both sides that would be a pretty sweet setup. Looking at 10s. Boxes would each get 500w at 1ohm to the subs.
...Frank

 

[Drake00XJ]

From what I unserstand, you should not put two subs facing eachother. While you can, it does not make for the most effecient set up as the two subs will cancel each other out. In other words, it will work but won't sound that great.

 

[BoXJer]

From what I unserstand, you should not put two subs facing eachother. While you can, it does not make for the most effecient set up as the two subs will cancel each other out. In other words, it will work but won't sound that great.

Which is exacly why I only built the one for my 10" and didn't make the one for the 8". Thanks to DotheDew, I saved myself some time and Money$$$.

 

[scoobyxj]

I have been thinking of making one up after the weather warms up for the side like you are preposing. I have two 10's and was thinking of removing the pannel to make use of the whole space. Coming acrost from the bottom of the window to the vertical line of the wheel well hump. I was planning on trying [I have never worked with it before] fiberglass, and finishing it with carpet. I may just try to make it MDF though if I have no luck with the fiberglass. My biggest problem will be keeping the rear from resonating, and vibrating the quarter pannel. If you end up doing thiss in the neer future I would be interested in in one for two Solobaric 10's [old style that are round]. If you don't want to do a possable just one for the two 10's. When you get the single woofer design done, and I see it mabey we could work somthing out for the two small displasment 10's. PS I also have a ZJ that is in need of a similer design box for two 12's.

 

[Rand McNally]

Hey BoXJer,

That brings up another question: Did you line your box with anything? Since fiberglass doesn't absorb sound like MDF does, do you notice any resonating? Does it rattle the back of your Jeep or does it sound pretty tight?

Before I go through with the building, I want to sound proof the whole cargo compartment with either Peel N Seal or something similar. Hopefully that will keep it from sounding like a coffee can full of bolts rattling around.

Also, what do you think of your Infinities? I need to get some new door/soundbar speakers and was looking at those. Thanks for the help!

 

[xjfrank]

Fire one out of phase with the other?

Those are the spots I have open, can you overcome any problems with locating the speakers there. I like fast, tight, clean bass. I'd even be stoked with 8s.

...Frank

 

[BoXJer]

Fire one out of phase with the other?

Those are the spots I have open, can you overcome any problems with locating the speakers there. I like fast, tight, clean bass. I'd even be stoked with 8s.

...Frank

DotheDew can chime in on this, I have no idea about reversing polarity on one of 'em. I know that's how isobaric boxes/chambers work, but I dunno about having the cargo area act as an isobaric chamber.

Rand McNally, as far as any rattles and unwanted resonance... none yet, but it's only been in action for a few hours driving to and from work since Sunday. The bass is clean and tight, but the sub isn't even broken in yet. Not getting the real low frequencies with it just being a ten, but most of my musical preferences don't go that low anyway.

The Infinities are much better than the 3 way pioneer 5.25"s I replaced with them. The mid-bass is very nice - the hair on my legs can feel it, but the soundstage isn't perfectly reproduced up front. It's just not aimed at my ears. The Infinity 6002i speakers have rotating tweeters that I aimed up and towards the opposite seat (drivers side speaker towards passenger headrest and vice versa), and that's really cool but the highs, although very nice - not too bright, are still not perfect. I wish I had gone with components up front with both a midbass driver and a seperate tweeter. Put the tweeters in the upper door panels. Or get kickpanels to accomodate the tweet and driver.

All in all though, I would recommend these Infinities...