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  1. #1

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    Default Am I Missing Out On Anything

    Hey All,

    I have a Polk Momo MM2154-DVC (Hope that code is correct) It' the dual VC 4Ohm 15" Sub,

    I currently have it in a 2.5cuft Single 4" Round Ported enclosure tuned at 35hz. While it does sound pretty awesome at the lower frequencies I fear I may be under utilising it's potential by not having it in a sealed enclosure?. Polk does state they can be used in any type of enclosure but were designed for small sealed.

    My question is what do you guys think? should I ditch the ported box and buy a prefab sealed?

    If so can you please state the pro's and con's of doing so

    Thanks in advance.

    (PS this sub is being driven by a Fusion Class D Monoblock amp which puts out 500rms @ 2Ohm)

  2. #2

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    Polk speakers are designed with SQ in mind. Therefore, most of the subs are designed around a sealed enclosure. Going sealed, you will lose volume for tighter bass. If you do go prefab, do a little math and figure out the volume of the box and make sure it is close to the recommended volume for the sub.

  3. #3

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    Quote Originally Posted by DSkip View Post
    Polk speakers are designed with SQ in mind. Therefore, most of the subs are designed around a sealed enclosure. Going sealed, you will lose volume for tighter bass. If you do go prefab, do a little math and figure out the volume of the box and make sure it is close to the recommended volume for the sub.
    What are the consequences for discussions sake of using the sealed box that maybe twice the capacity of recommended?

    Also generally how significant is the loss in volume compared to ported?

  4. #4

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    Perhaps someone out there might have been through a similar dillema? problem is i love the low notes therefore sceptical about moving to sealed, and I'm quite concerned about the loss of "volume" i mean will it be like 50% quieter?

    But on the flip side to that, I would hate to find out I'm missing out on so much more (better) performance by having it in a sealed unit.

    It feels like such a huge decision

  5. #5

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    Your not missing anything with a ported enclosure. One problem with your enclosure is that you do not have enough port area for that subwoofer. Another may be build quality. Did you have it custom made or is it a pre-fab unit? If you go with sealed then your box volume drops to 1.5 cubic feet. I think that is small for a 15" subwoofer. Even though it is designed to work in this cabinet sometimes going larger will yield better results. The volume you will lose is about 3db. That is what you usually pickup from the sound from the port. What that means is you will hear a difference but maybe only about 10 to 15 percent. Personally I would try the woofer in a ported enclosure tuned to 29 hz and see how you like it. Some of this also depends on the type of vehicle it is in. What do you drive?

  6. #6

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    Quote Originally Posted by Installer4life View Post
    Your not missing anything with a ported enclosure. One problem with your enclosure is that you do not have enough port area for that subwoofer. Another may be build quality. Did you have it custom made or is it a pre-fab unit? If you go with sealed then your box volume drops to 1.5 cubic feet. I think that is small for a 15" subwoofer. Even though it is designed to work in this cabinet sometimes going larger will yield better results. The volume you will lose is about 3db. That is what you usually pickup from the sound from the port. What that means is you will hear a difference but maybe only about 10 to 15 percent. Personally I would try the woofer in a ported enclosure tuned to 29 hz and see how you like it. Some of this also depends on the type of vehicle it is in. What do you drive?
    Hi, thanks for you input that does indeed clarify things allot more, my enclosure I had custom built 2.5 cubic foot with a 4" internal diameter circular port (single port) which is about 6" long from memory (I saw the ported construction on the polk website) from memory I'm pretty sure it was tuned at 35-38hz the box was made from 3/4 mdf and all joins internally were sealed with some dark brown/black sealer (don't ask me what it is haha) as for the vehicle it's in I'm not sure you will know what it is (I live on the opposite side of the world) New Zealand none the less its a 2006 Holden VZ Commodore (Australian General Motors Holden with a Chev LS1 engine), from memory I believe you have the equivelant 2 door model in the US called the Chevolet GTO? (mine is a 4 door sedan) I think your GTO is a 2 door coupe from memory?

    It's a pretty big sedan however, maybe slightly smaller than the Chrysler 300C?

    Hope that helps alittle.

  7. #7

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    If you have the ability try the following enclosure. 23.75" by 17" by 18.125" (width X height X depth). The port will be 1.5"X15.5"X36.25. The area of the port is 23.25 square inches which is twice what you have and what Polk reccommends. This enclosure volume is 2.5 cubic feet (net) with a tuning frequency of 25hz. With that large of a car you should be fine. I have used this enclosure several times and it is designed for a subwoofer with similar specs to the Polk you own..
    Last edited by Installer4life; 07-28-2010 at 02:43 AM.

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