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Joe X

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Posts posted by Joe X

  1. You have 2 different issues that you should not confuse:

    1) what enclosure is better for a particular sub.

    2) what type of enclosure is better for a particular cabin

    For question 1 you calculate the following as a general rule:

    EBP = Fs/Qes

    <50 sealed.

    >100 Ported.

    between 50 and 100 you could use in either.

    For question 2 sealed will usually give you better transient response and lower group delay plus this:

    Since sealed has a roll-off of 12dB/octave and cabin gain raises at 12db/Octave starting at 50-90Hz you can get to cancel each other giving you a perfectly flat low frequency response. So properly used sealed is best for SQ. If your cabin is huge you can't get that and then ported is the better way to get bass.

  2. 9cuft@30Hz port area should be 90 sqin, it will be a huge box!

    10 sq inches of port per cube... wow :No: but 32-35 is good for daily like fmedina said and box will also vary with power you plan to run

    I know it's 12-16 but I went by the Alpine manual multiply Vb x 4 and Port area X4, I mean I am hoping alpine knows what they are doing.. right??? Also they suggest to tune to 30Hz look it up...

    ok so where did you get 90sq inches of port from? im confused here

    Download SWR-1542D.pdf from somewhere look ay optimum ported enclosure and find that the recommended vent area per sub is 22.5 multiply that x 4 and you get 90 sqin, of course you have to calculate the lenght by formula.

  3. 9cuft@30Hz port area should be 90 sqin, it will be a huge box!

    10 sq inches of port per cube... wow :No: but 32-35 is good for daily like fmedina said and box will also vary with power you plan to run

    I know it's 12-16 but I went by the Alpine manual multiply Vb x 4 and Port area X4, I mean I am hoping alpine knows what they are doing.. right??? Also they suggest to tune to 30Hz look it up...

  4. The PVC pipe can stay inside with one cap to each end no need for it to come out, obviously the reduced Vb will increase tuning frequency, you can just keep taking up more Vb until you get the 30Hz.

    If you have the full dims of the port (cross-sectional area and centerline lenght) I could better estimate or you can do it if you know the equation.

  5. I think im going to go with the aq 1200 . Hoping to see a major improvement !

    Expect greater efficiency easy on your electrical system and will not run hot, of course better output, regarding SQ not everyone likes it that much, if you care or even can listen a JL will still be better.

  6. You are not going to get any true bass from 6x9s, you get midbass at most, no matter how many you put, those speakers will not perform well on boxes, are designed to work in infinite baffle settings like your rear deck, will loose low end. 3 way will pickup earlier midrange frequencies which the big oval driver can't reproduce accurately.

    There are very good and inexpensive subs to choose from that will get you real bass (30-40Hz). Take a look:

    MB-Quart-FWA-304D

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