want to down size, 12'' woofers

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=113742
Printed Date: May 15, 2025 at 8:12 AM

Topic: want to down size, 12'' woofers

Posted By: rlemere
Subject: want to down size, 12'' woofers
Date Posted: May 11, 2009 at 8:58 AM

Hi everyone, I am a newby here so be easy. I recently bought a 2007 Ford Expedition and it came with a sub box with 3 Polk / Momo MM2124DVC woofers. The box measures 47.5" W x 11" D x 14" H, They are in a custom built box that runs across the back end of the SUV and I would like to either have one 12" sub on each side in a wedge type box or was thinking of building a sub box for two 12's to sit in the middle of the floor next to the 2nd row of bucket seats.

The current box is around 2.2 c.f. with 3 subs and the one I am considering to build is around 1.5 c.f. My question is will this smaller cubed box work for two 12's? I have a Polk C-500.1 Carbon Series amplifier running the bass and it hits hard and loud like I like it. Thanks in advance for the advice and or help

Roger

Replies:

Posted By: vibrationcustum
Date Posted: May 11, 2009 at 9:46 AM

box is to small for even one of the speakers.
here is the specs for one sub
Recommended Enclosure      Sealed / Ported / Bandpass
Resonant Frequency      31 Hz
Qms      6.06
Qes      0.61
Qts      0.55
Vas      2.249 cu.ft. / 63.71 L
Sd      80.4 sq.in. / 518.7 sq.cm.
Xmax (linear)      .37 in. / 9.5 mm
Xmax (mechanical)      .75 in. / 19 mm
Le      2.29 mH

but if you give me LxWxH between the seats I make you something for the 2-12' let me know.

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Can't be loud then don't have it.

(power acoustik system)
Head unit- TID-896 7" TOUCHSCREEN
ovn1-5500d 09 and another one coming soon
4-12" mofos 12ft3 box to 40hz (wall)
2 batterys, 1 power

Posted By: rlemere
Date Posted: May 11, 2009 at 3:08 PM

Thanks for your input, what if my dimensions of the box were 24" W x 14" H x 11" D? That is what I have started with, would it work if I go with the Isobaric method? This is something I can build just need help with the size.

Roger

Posted By: vibrationcustum
Date Posted: May 11, 2009 at 4:05 PM

well if you want to put them between the seats I got something the I can design if you want them there. Just need to know LxWxH posted_image

this will hold 2 subs

Got the design done with a stealth look to it. No one will see the subs but will hear you and you will have the full back for things.

-------------
Can't be loud then don't have it.

(power acoustik system)
Head unit- TID-896 7" TOUCHSCREEN
ovn1-5500d 09 and another one coming soon
4-12" mofos 12ft3 box to 40hz (wall)
2 batterys, 1 power

Posted By: rlemere
Date Posted: May 12, 2009 at 12:31 AM

Dimensions are in my second post, would isobaric work with this dimension?

Posted By: vibrationcustum
Date Posted: May 12, 2009 at 11:44 AM

I dont thank so because it is still using the same air space but there is one why to find out is to do it.

ok there are 2 of the first one is the stealth design and the out dims are 24w x 14h x 30d with a port of 1.5 wide so if you have room each sub is tuned to 35hz and 1.5ft^3per side and no one see what you got.
posted_image

number 2 simple but that the dims are that you gave me it would have to be sealed or the port will go into the seat.
posted_image

need any more help let me know

-------------
Can't be loud then don't have it.

(power acoustik system)
Head unit- TID-896 7" TOUCHSCREEN
ovn1-5500d 09 and another one coming soon
4-12" mofos 12ft3 box to 40hz (wall)
2 batterys, 1 power

Posted By: aznboi3644
Date Posted: May 12, 2009 at 12:14 PM

middle row is no optimal for cabin loading...but if you must than there is no choice

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Custom Enclosure Design

Posted By: vibrationcustum
Date Posted: May 12, 2009 at 12:39 PM

I am just the designer, just asked me to make something to the specs that I got. With that truck it would he hard to cabin load with the subs anyways so if he would want really hard bass he would have to upgrade anyways. I might be wrong but I thank he is looking for a bump but not to take up so much room in the truck. Both boxes and even the box that he has now is to small for the subs. Who knows

-------------
Can't be loud then don't have it.

(power acoustik system)
Head unit- TID-896 7" TOUCHSCREEN
ovn1-5500d 09 and another one coming soon
4-12" mofos 12ft3 box to 40hz (wall)
2 batterys, 1 power

Posted By: aznboi3644
Date Posted: May 13, 2009 at 12:51 AM

Yeah...IMO best way to load the subs/enclosure is downfiring with the port firing down if there is enough room to port.

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Custom Enclosure Design

Posted By: rlemere
Date Posted: May 13, 2009 at 11:13 AM

Thanks for the info guys, not sure what is cabin loading? I am just looking to move my subs to open up the back of my SUV. My current box blocks the access in the rear with the 3 12's in it. Vib you said that my current box is not the correct sixe for these woofers? It measures 47.5" W x 11" D x 14" H and does sound really good to me. C.F. on that box measures 2.212. I would like to do this once and have at least close to the amount of bass I currently have. I suppose it would be best to downgrade to 2 10" woofers for the size box I want to put in the middle console? I would like to stick to the smaller dimensions and could seal the box (second pic) Would the woofers have to sit on top of the box or could I put one in front and one in back?

Even if I had to only run one 12" sub that would be okay, but I was under the impression that the more woofers you have the harder they will hit?

Posted By: aznboi3644
Date Posted: May 13, 2009 at 8:09 PM

We are just saying that middle console of an SUV is not the optimal location for the best transfer function. Cabin gain sucks in the middle basically.

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Custom Enclosure Design