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Tuning a ported Sub enclosure.

Discussion in 'In-Car Entertainment' started by Jay, Aug 10, 2008.

  1. Jay
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    Jay Member

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    [Aug 10, 2008]
    I have an Alipine 12" type R sub in a ported Alpine enclosure. I was wondering if it could be tuned to around 30hz? and how i would go about doing this?
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  2. Simon Singh
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    Simon Singh BMW Expert

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    [Aug 12, 2008]
    How do you mean tuned to? To cut off after 30hz?
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  3. dualmono21
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    dualmono21 Well-Known Member

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    [Aug 12, 2008]
    depends on what you mean ?
    do you mean so as the port itself is tuned so as its peak effiecency is at 30hz ? or do you mean you only wish to play music which is above or below this frequency ?
    to stop music below this frequency with a ported enclosure you will need to use a subsonic filter (most good amplifiers have them built in )
    i cant imagine why you would want to ... but if you mean you only wish to play music upto and including 30hz then youll need a low pass filter set to 30 hz
    the box the port and the speaker interact and work as a team it will really depend on what tuning frequency its tuned to now if its fairly high
    then the only way youll be able to achieve a tuning frequency of 30 hz will be by re-designing a new box and port
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  4. Jay
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    Jay Member

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    [Aug 14, 2008]
    thanks, looks like it would be easier to buy a sealed box than to redesign a box and the port.

    Next question is would my Mono Alpine M605 amp be able to run 2 12" 1242 type R subs wired in parallel or would I need to buy a new amp?
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  5. dunk
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    dunk Member

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    [Aug 14, 2008]
    if its already in a ported alpine enclosure, why do you want to change things?

    if its the swr 1242d sub, then it should live in a sealed box of around 38L, or a tuned box between 45-85L for each sub - quite a big box.

    the 45L tuned box would have a f-3 i.e. -3db point at about 25hz, but its a very peaky boomy box and would only play bass at 1 note (my opinion only) according to the calculations
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  6. Jay
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    Jay Member

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    [Aug 15, 2008]
    Exactly...with the new HU I find that its drowing out the music from the fronts. I tested a 12" in a sealed box and it sounded so much better.

    Any ideas on my problem

    "would my Mono Alpine M605 amp be able to run 2 12" 1242 type R subs wired in parallel or would I need to buy a new amp?"

    cheers
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  7. AndyMac
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    AndyMac Moderator Staff Member Moderator

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    [Aug 15, 2008]
    That amp should be fine as it kicks out 600wrms at 2 ohms. Your 2 subs in parallel will provide a 2 ohm load.
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  8. dualmono21
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    dualmono21 Well-Known Member

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    [Aug 15, 2008]
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  9. Jay
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    Jay Member

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    [Aug 15, 2008]
    #9
  10. two
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    two New Member

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    [Aug 15, 2008]
    custom box which is design to work with your speakers specs
    bass box pro is a great piece of software that does the maths for you
    (also winisd)
    bass box pro help file give a good commentary about different speaker box designs
    i'm about to pop out.. but could work out a box size at some point over the weekend
    #10

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