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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