Question about Alpine Type-R SWR-1242D Car Subwoofer

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What size enclosure (sealed)for Alpine 12"1242D(METAL Music)

Have 12"1242D Alpine sub. Car is a Mitsubishi Eclipse. How many cubic ft. of air space should I have for best sound with an sealed enclosure. I don't listen to rap or country, Just hard rock and heavy metal. Any suggestions?

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  • Josh Murphy May 11, 2010

    I have designed many boxes in my years. 30 years old now. I have found by far, the best sound is sealed with a hatchback type car for rock. What year and model eclipse so i can see the rear hatch style. I can draw out some specs for you.



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  • 12" subwoofer with dual 4-ohm voice coils
  • Kevlar reinforced pulp cone with Santoprene™ rubber surround
  • cast aluminum frame with perimeter venting
  • frequency response: 25-500 Hz
  • power handling: 200-500 watts RMS (250 watts per coil)
  • peak power: 1,500 watts
  • sensitivity: 85 dB
  • top-mount depth: 7-5/8"
  • sealed box volume: 0.57-1.0 cu. ft.
  • ported box volume: 0.75-2.0 cu. ft.

  • For rock, i actually have 2 seperate 12's in slot port boxes i built facing forward. Facing forward reduces a little resonance and spl, but keeps alot of that annoying rattle off your tag lol

    Hope this helps :)

    Posted on May 05, 2009

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    What size box is best for 2 alpine type r's

    Posted on Nov 21, 2010


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    I have a alpine 6013 sub, what should i tune the port to? i listen to mostly rap if that makes a difference.

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    This really depends on the subwoofer. All subs are NOT alike. I would recommend visiting the manufacturers website for more information. Typically 1-1.5 cubic feet works with most 10 in subs. But again, please check the manufacturer for more specific instructions.

    Sep 06, 2011 | Panasonic Car Audio & Video

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    You have a lot of choices for this. First, unless you are tuning the sub to a specific frequency you have options. You didn't specify the size of sub so it's difficult to say specifically, but if it's a 12 inch sub, you need about 1.5 to 2 cubic feet. Of course the performance of the sub depends on the music you listen to. If you listen to rock, pop, classical, or country, I recommend a sealed box. A sealed box gives you better control over your sub. The air acts as a cusion and decreases the return time of the cone to rest position. This gives you tighter bass. If you listen to rap or hip hop, I recommend a ported enclosure. This type of enclosure allows for more cone excursion, thus allowing the sub to recreate lower frequencies. Hope this helps.

    Aug 12, 2011 | Pioneer TS-W304C Car Subwoofer

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    I have a 15 inch legacy sharp steel 4000w subwoofer. how much air space does the enclosure need to have? and does it matter if it's sealed or ported?

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    Feb 25, 2010 | Car Audio & Video

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    I need to know the demensions for 10 inch subs

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    Jan 30, 2010 | Koiiler XM-6715 Car Subwoofer

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    Box recomendations

    It depends on the size of the subs- 8z 10z 12z 15z? whether or not you port the box is up to you- a ported box is generally louder than a sealed box -as you are coupling and tuning the sound from the rear of the driver with the sound generated from the front of the sub- but the box is also generally larger as well.Then aside from your preference of ported/sealed you have to account for the recommendations of the manufacturer as to whether the sub/speakers are meant to be placed in a ported or sealed enclosure. Most 10 inch subs do well in a box that yields .75 cubic feet to1.0 cubic feet.most 12z do well in 1.0 cu feet to 1.5 subic feet and 15z do well in 1.5 to 2.5 cubic feet. I have a set of 15z that require 4.25 cubic feet per sub-so its important to look into the manufacturers recommendations. The easiest box to make would be a sealed enclosure-and the sound quality generally yields a tighter more accurate bass sound along with increased power handling capability- try going to rockford fosgate .com and look into the woofer box wizard its a program that calculates air space for whatever size box you have room for-hope that helps you-good luck

    May 11, 2009 | Car Audio & Video

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    What type of enclosure for audio bahn aw1000x

    I used to be an Audiobahn dealer and can help you with the box. However I can't find specs on that model in my records or on Audiobahn's website. If you email me ( the Theile Small parameters for the subs I can give you more exact specs. The box should be ported (Audiobahn doesn't recomend a sealded box) with about 2.5 cubic feet, made of 3/4" MDF. Here are some generic specs that should go well with that particular sub.

    Air Space (Cu. Ft.) 2.4

    Port Size (Inches) 4 x 6.25

    Tune Freq. (Hz) 39

    Mar 31, 2009 | AudioBahn AW1000X Car Subwoofer

    1 Answer

    Size of boxes

    Wow you are in luck, I used to be an Audiobahn dealer. Designing sub enclosures is my fulltime job. So here you go.-
    If you are looking for sound that is very smooth, and has a very low end shaking everything setting off car alarms. You will need a PORTED BOX that is 3 CUBIC FEET FOR EACH SUB WOOFER. It actually calls for 2.7cu.ft but after you add speaker displacement and bracing it should be at least 3 cu.ft. The port can be either round or square made of plastic or 3/4" wood respectively. My port suggestions are dependent on how much space you have. The shortest round port might make some noise (too much pressure!). So think about that first. Anyway the short port is 3" diameter and 15.5" long. The longer port is 4" in diameter and 28.25" long. The rectangular wood port can also be either (port measurements are inside diamensions) 3" w x 3" w x 18.5" long (short port) or 2 w x 10.5 h x 48' long. The second longer wood port is recommended most but will take up a lot of space. The fact that you have to subtract the port volume from the box makes for space issues in cars. Also the second wood port sounds better and won't make much wind noise, but takes up .75 cu.ft worth of space. So in plain english your box will have to have an internal volume of 3.75cu.ft. An example of this could be made of 3/4" thick MDF, have 1" x 1" internal bracing and measure (box dimensions are external and assumes the use of 3/4" MDF) 12" h x 18" w x 30" deep. The port is an integral part of the box fitting inside. I'm sorry I can't provide any drawings to make things easier. Now this box size is one that I ran through a computer program I use. So it is not the same as the manufactures recommendations. I will list those as well.
    The second box is an example using a round short port and also uses 3/4" MDF, 1 x 1" bracing, the 3" dia x 15.5" long port, and measures 12" x 18" x 24" externally.
    If space is an issue try checking out the information below. -I got it from Audiobahn-
    If for some reason it doesn't show up or you need assistance let me know. Good luck and enjoy your new setup-I'm sure you'll be happily disturbing the peace soon!
    Model # AW1006T
    Air Space (Cu. Ft.) 0.65
    Port Size (Inches) 2 x 6.5
    Port Vel. (%) 48.31
    -3dB (Hz) 31.5
    Tune Freq. (Hz) 40
    Sub Disp. (Cu. Ft.) 0.21
    Port Disp.(Cu. Ft.) 0.01
    Total Vol. (Cu. Ft.) 0.75
    Air Space (Cu. Ft.) 1.4
    Port Size (Inches) 3 x 6.75
    Port Vel. (%) 24.19
    -3dB (Hz) 30
    Tune Freq. (Hz) 39
    Sub Disp. (Cu. Ft.) 0.21
    Port Disp.(Cu. Ft.) 0.024
    Total Vol. (Cu. Ft.) 1.5
    Air Space (Cu. Ft.) 2.4
    Port Size (Inches) 4 x 6.25
    Port Vel. (%) 14.39
    -3dB (Hz) 29
    Tune Freq. (Hz) 39
    Sub Disp. (Cu. Ft.) 0.21
    Port Disp.(Cu. Ft.) 0.04
    Total Vol. (Cu. Ft.) 2.5
    EBP 74 80 80

    Sealed NR NR NR
    Minimum (Cu. Ft.) 0.5
    Maximum (Cu. Ft.) 1
    SPL (dB) 80
    All sealed boxes already include the displacment for the subwoofer. NR = (Not Recommended)

    Mar 08, 2009 | AudioBahn AW1006T Car Subwoofer

    1 Answer


    According to MTX they need 1.25 cubic ft per sub sealed and 2 cubic feet vented. Most pre-fab boxes will work for those subs.

    Jan 06, 2009 | MTX Dual 12" Subwoofer Enclosure (Bs212s)

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