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Thu Dec 28, 2006 3:21 pm

I'm building a box for the subs behind the backseat. dimensions are 36" wide by 12" deep by 12" high...do I need to seperate the enclosure for each 10" sub or can I install both subs in the same box? Sealed enclosure, no ports.
Thanks

Thu Dec 28, 2006 3:33 pm

Pretty sure you would need to separate each sub. I don't believe they need to share the same air space.

Thu Dec 28, 2006 3:38 pm

You can learn a lot from this guide:
http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/reviews/20030701/build_box.html

Thu Dec 28, 2006 3:50 pm

It depends on how you're running them but generally you will get better sound if they are seperated. The only way to run them together is if they are running on the same channel and moving together. Even then, they should still be seperated. That will allow you to run at least one if the other blows up or something. If they are running on different channels, that can damage the subs since they are not exactly moving together (IE the left channel has more bass output than the right)

Thu Dec 28, 2006 4:06 pm

not true. read the "speaker cookbook"

Thu Dec 28, 2006 4:10 pm

Erik G wrote: not true. read the "speaker cookbook"

What's not true about it. If you run 2 speakers in the same box on seperate channels they are more likely to interfere with eachother than if they were seperate. If they are run on the same channel it's ok but you can't really use even just one if the other blows because then you'll have twice the needed speaker box size.

Thu Dec 28, 2006 4:19 pm

2-subs in one enclosure will be fine. Run you amp mono or both speakers to a bridged amp if possible. Most low bass is recorded mono, so there probably won't be much difference between L and R channels anyway. A box behind the seat will have just about the right volume for 2-sealed 10's. Better yet, here's some good software that I use for speaker design. It will allow you to design a single box with 2 or more drivers - assuming you have all your speaker parameters available.

http://www.linearteam.dk/default.aspx?pageid=winisd

Thu Dec 28, 2006 4:44 pm

Running two subs in 1 sealed, first order enclosure will work just fine. As Chad1376 pointed out, wire the two subwoofers in a parrallel configuration to yeild a lower ohm load. This in turn will allow your amp to be bridged and allow the greatest efficiency from your amplifier.

Thu Dec 28, 2006 4:58 pm

Another tip (can you tell my mind is wandering at work today)...

Build the box out of birch plywood (good plywood, not the cheap stuff). Birch is lighter, and alot easier to cut, drill, and drive screws than the particle board / medite crap. It's worth the extra $$.

Thu Dec 28, 2006 6:42 pm

Well the box has already been started and it is made of 3/4 MDF..jus waiting for the glue and silicone to cure before installing the top piece and the subs, and possibly the "divider"
The subs are 10" KICKER dual voice coil 4 ohm. Each sub is going to be driven by a KENWOOD 8452 4 channel 800 watt amp. I can bridge the "B" side of both amps and they have the built in low pass filter on that side.
If I have read the specs correctly I "can't" wire the subs in parallel, that will give me 2 ohm configuration and the specs on the amps warn specifically against doing that. The tech where I got the subs said that 2 ohms will damage my amps. If I wire them in series it will yield an 8 ohm configuration.
Still have to figure out where to install 2 6x9's and 2 6 inch seperates in the back also. Anybody have any pictures of something similar???

Thu Dec 28, 2006 7:46 pm

JOKER2RIDE wrote: The subs are 10" KICKER dual voice coil 4 ohm. Each sub is going to be driven by a KENWOOD 8452 4 channel 800 watt amp. I can bridge the "B" side of both amps and they have the built in low pass filter on that side.
If I have read the specs correctly I "can't" wire the subs in parallel, that will give me 2 ohm configuration and the specs on the amps warn specifically against doing that.

DO NOT wire all 4 voice coils in parallel then. Use 1 voice coil per speaker to yield the 2ohm load. If you had a high current amplifier that was stable down to 1ohm, then you can wire all 4 voice coils in parallel.
But if you insist on wiring all 4 voice coils, it can easily be done. Wire the two voice coils per sub in series, then wire both subs in parallel. That will yield the 4ohm load that your amplifier will "see"

Thu Dec 28, 2006 8:56 pm

in my chevy i have 2 twelve inch JL 12w0s in a JL power wedge box.

They are wired together and are bridged to a 500watt power akoustic

works great and sounds sweet. I have set off many car alarms with it - i love it

Nick

Fri Dec 29, 2006 11:59 am

I ran two Soundstream DVC 10s with the coils wired in parellel and the speakers wired in series and the amp bridged. 1 ohm. Old Rockford Fosgate amps can handle it, even though the manual says not to. I never had any problems with them sharing volume in my sealed box.

Mon Jun 14, 2010 4:00 pm

JOKER2RIDE wrote: I'm building a box for the subs behind the backseat. dimensions are 36" wide by 12" deep by 12" high...do I need to seperate the enclosure for each 10" sub or can I install both subs in the same box? Sealed enclosure, no ports.
Thanks Use 3/4" mdf home depot about $8.00 for a 2'x5' sheet you might need a sheet and a half.I'd try to get subs with a higher spl that way you don't have to amp them up too much.
If each sub requires 1 to 1.25 or so cubic ft. you should be fine run them in mono on the amp.you can always get two dual voice coil subs and get 4 ohms out of them. if not just use both channels.I staple fiberglass insulation(the pink or yellow stuff home depot they have small bags of it) to the inside walls of the enclosure.
In my 74 bug,I have two 10" JL audio 8 ohm subs wired in parallel= 4 ohms to the amp. I have a 500W CRUNCH with a 25 amp fuse for my bug I also have two 5.25" coaxials on each side of the subs. two more in the front with another CRUNCH amp a four channel 600w with another 25amp fuse. and a capacitor. I didn't want to mess up my alternator
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The formula for cubic ft. is inside inches lenght x width x hight divided by 1728 this gives your box 2.32cu.ft. you can always go smaller if your box is already built by piecing up the inside of the box. If your box is a little small the fiberglass will make it sound like it's in a larger box.

I also built a ported fiberglass box for my brothers bug with a single sub the enclosure volume is 1.35 cu.ft in both types of these enclosures the coaxials are on the outside the sub box.
The fiberglass box really wasn't that hard to build. My port is removable so I can use a different lengths of 3" port in case I use a different subwoofer.
Here's the process the fiberglass cloth is applied to the underside.

Oh yeah, If your looking for sound deadening material instead of paying alot for dynamat($10.00 per sq.ft.) Go to the roofing section of home depot or lowes there is a product called Quick roof. It's pretty much the same thing.w/foil on one side. It's about $17.00 for a roll 25'x 6".

Mon Jun 14, 2010 6:40 pm

As was said before multiple bass drivers in a single enclosure is fine as long as they get the same signal ($75,000 home loudspeakers can't be wrong). But you have a mismatch of componets. Your bridged amps can only handle a 4ohm load. The only way to do that is wire the two drivers into a 4ohm configuration and run off one bridged output of one amp. With two 4ohm dual voice coil drivers your impedence options are 8, 4, 2,and 1 ohm. Wiring them at 8ohm each will yeild only about half the speced bridged rating, very easy on the amp, but not what you're after i'm guessing. I would suggest selling one of the amps and getting one of Kenwoods mono class d subwoofer amps and wire your drivers for 2ohms, they can be found fairly cheap online. I would also bridge the other amp 2 channel to power the front speakers and be done. Rear fill is only a volume booster and does nothing but interfere with stereo imaging and soundstaging. When was the last time you were at a concert and the band played behind you?
Good luck with your set up. Audio is a fun hobby!!

Wed Jun 16, 2010 3:13 pm

To be quite honest, a single 10" QUALITY driver is probably all you need. I recently redid the system in my GLI and i have a single P3S in a tiny tiny box that sits behind the wheelwell and with a good amp, its enough to piss off the neighbors quite easily.

Wed Jun 16, 2010 8:22 pm

I would go with one 12" dual voice coal speaker...IMO

Thu Jun 17, 2010 5:18 am

Major Woody wrote: I ran two Soundstream DVC 10s with the coils wired in parellel and the speakers wired in series and the amp bridged. 1 ohm. Old Rockford Fosgate amps can handle it, even though the manual says not to. I never had any problems with them sharing volume in my sealed box.

Actually lower than that, but not for very long :wink: Worked in an install shop ages ago. Got a Punch45 to what we could estimate to 1/4 ohm. With in a couple minutes it melted! Beat the crap out of everything hooked up to it until it did. Looking back I wish I still had one of those!

Sat May 12, 2012 4:44 am

JOKER2RIDE wrote: I'm building a box for the subs behind the backseat. dimensions are 36" wide by 12" deep by 12" high...do I need to seperate the enclosure for each 10" sub or can I install both subs in the same box? Sealed enclosure, no ports.
Thanks
I got off subject.....No you shouldn't need to separate the the subs if you run your amp in mono. My two JL subs are in the same box undivided, my full rages on the side of them are divided from the subs though. You will need to find some subs that are good for smaller perimeters, as it is you have roughly 2.5 cu.ft to work with (that's inside of the enclosure) and that is a fair amount of room for 2 ten inch subs. Many subs today are made for smaller enclosures, flat subs are made for small boxes also.
If you feel that your enclosure is possibly too small fill it with either dacron fiber (pillow stuffing) or staple fiberglass insulation to the inside of the box. It makes a huge difference than just keeping it empty and makes your box sound bigger than it actually is.

I'd try to get a sub with a higher spl rating also maybe around or greater than 90db, that way you don't need to have a huge amp to drive them. also your amp should have a spl rating of greater than 95db also. Don't forget a capacitor also, you can pick up a 2 farad cap.(1 farads=1,000 watts....2 farad=2,000 watts and so on) on Amazon for about $30.00. it will save your alternator/ generator.
I would consider getting an equalizer with a subwoofer control on it also, doesn't have to be expensive but check the specs first off for decent spl and thd levels, mine is a Boss audio eq1208 it cost about $40.00

Sat May 12, 2012 11:13 am

i had a box with 2 10s with no separation in the box sounded like crap subs fought each other defiantly separate.