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ported or sealed 2 15 inch subs 1000 watts each

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  • ported or sealed 2 15 inch subs 1000 watts each

    whats up!!!! well its not a car question but ive got two jbl 15 inch woofers and i want to make a subwoofer box for it... i want a THUMP i dont care about the throw its going to be for like home theater kinda stuff and small parties... ive got a 1800 watt qsc rmx1450 dj amp to push it at 900 watts each help me :-D im going to use 2 layers of 3/4 inch mdf

  • #2
    well

    ported gives you dirtier louder bass, larger box, more time to build (only slightly)

    sealed gives you cleaner, more responsive bass, smaller box, quicker to build

    simple as that, you have to decide which one you want
    Jan Bennett
    FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

    Please post on the forums! Chances are, someone else has or will have the same questions as you!

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    • #3
      from what my audiophile friends tell me ported is a bit more sloppy, as afore mentioned.. but better frequency response .. (most in home theater systems use ported) .. I use ported. and only run 100W to each ..

      hey I'm gonna be a dad here soon .. I can't run lots like you young kids!
      Shawn



      Check out my web company Minneapolis Web Designer | MODx Web Design - Himmelberger Design

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      • #4
        Ported boxes loose subwoofer control around tuning, so just tune it LOW, like 17Hz or so... i've never heard any early 20Hz tones that needed punchiness Above tuning, the ported box wont sound any worse than sealed, and actually in some cases can sound tighter, it all depends on the drivers Qts

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        • #5
          don't forget resonance chambers.
          http://jupiter.walagata.com/w/djpm05/sig.jpg

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          • #6
            For sealed enclosures you need more powerfull amps than with the ported ones, but the sound is cleaner. Basicly, the difference between the two, or at least how I see it is, with the ported enclosures, you get the bass that's really ****ed at your lungs, when with the sealed enclosures the bass just hits you in the back of the head, really hard. I for one, like the ported ones...
            Renault Megane...the OEM look

            The Lost in Europe Ford Escort

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            • #7
              What is the model of the subs?

              I really doubt that you need to double MDF everywhere... MAYBE on the face of the box, but that would be it. It takes a pretty good sub to require more than 3/4 everywhere, especially if ported.

              Originally posted by Blackrazor
              Ported boxes loose subwoofer control around tuning, so just tune it LOW, like 17Hz or so... i've never heard any early 20Hz tones that needed punchiness Above tuning, the ported box wont sound any worse than sealed, and actually in some cases can sound tighter, it all depends on the drivers Qts
              You should never tune below the Fs from what I have heard.

              For movies, you want a sub with a Fs below 20hz, and tune it as low as you can, but for music, tuneing to 30-35hz is typical. True, some songs have notes below 30-35 hz, and it isnt a good idea to play under the tuneing frequency, but as someone once said to me "just as long as you dont play 20hz sine waves for 30 seconds straight, you will be fine"

              Matt

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              • #8
                one thing to keep in mind - if youa re looking to compete you will want the box tuned higher (like 50-60Hz), but it won't sound nearly as good as if you keep it tuned around 30 Hz...just something to consider
                Jan Bennett
                FS: VW MKIV Bezel for 8" Lilliput - 95% Finished

                Please post on the forums! Chances are, someone else has or will have the same questions as you!

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                • #9
                  hmmm well wow thas some awsome input :-D ive attached the specs of the subs and the amp here they are...

                  SUB
                  Low Frequency Driver: JBL M115-8A
                  Frequency Range (-10 dB): 38 Hz - 16 kHz
                  Frequency Response (3 dB): 50 Hz - 12.5 kHz
                  Sensitivity (1w/1m): 98 dB SPL
                  Nominal Impedance: 8 ohms
                  * Power Capacity: 250 watts
                  * Peak Power Capacity: 1000 watts

                  the woofer is being taken out of a full range jbl jrx 115 speaker
                  http://www.jblpro.com/JRX/JRX115.htm

                  amp
                  http://www.qscaudio.com/products/amps/rmx/rmx.htm
                  im using the qsc rmx 1450 amp

                  THANKS GUYS!!!

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                  • #10
                    I would just take the dimensions from this to make your box
                    http://www.jblpro.com/JRX/pdf/JBL_JRX115%20final.pdf

                    To me, it looks like its about 3 cubic feet in that box, maybe a little less, but a box like this should be alright

                    W: 17 1/2
                    H: 28
                    D: 10.5

                    Might wanna make it a little smaller, so this might be better (2.5 cubes)

                    W: 16 1/2
                    H: 26 3/8
                    D: 10

                    All measurements in inches, and inside diameter.

                    Doesnt appear to me to be ported, but maybe I missed somethign on the picture. I am sure if it sounded better ported, it would be ported for their setup.

                    Matt

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                    • #11
                      Since you don't know the speaker's TS specs, you want a sealed box. Randomly picking a tuning frequency for a ported box when you don't know the speaker makes for blown subs and crappy sound.

                      DJ speakers are NOT subs. They will not play the 30-40 Hz stuff like you're hoping they will. I'd stick with your JL 12's. Also, at 8 ohms they'll be cutting your power in half, unless you wire them in parallel on a bridged amp that can support only 4 ohms. If it can do 2 ohms, you're missing half your power.
                      2005 Subaru Legacy GT
                      Status: 40% - starting install

                      AMD Sempron 3100, Biostar K8NHA PRO mobo, 512 meg DDR, WD 200 gig SATA, Opus 150, Xenarc
                      JBL GTi 6.5 fr, JBL 5.25 rr, (3) JBL 75x2 & 1 1200x1 amps, PA MOFO 12 sub

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                      • #12
                        oh naw john m its not for the car :-D i do mobile sound ive got two dual 15 inch speakers right now and i dont use these single jbl 15s so i wanted to run em off my seccond amp as a dual box of subs the jls are staying ofcrouse :-D haha

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                        • #13
                          hey mbuchman there is two little ports in the main speaker box and it has a HORN also which im not going to be putting basicly im looking for the kinda sound that u FEEL in a hall but cannot hear from far untill you get like within 25 feet range... and i know for sure that these speakers can push bass like no other ive ran em off a xover on the subwoofer output and it sounded awsomeeee... or my other option is leaving it in the same case i got it in and just not using the horn on it and pushing only the lows to it .... so yeah keep em comin thanks for the help guys! u rock!

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                          • #14
                            Ohhhhh - makes more sense now!!!

                            You'll want to duplicate the dimensions of the cabinets they're in now (can make one with internal divider). As long as they have the same cubic ft. and the same ports (copy the diameter & length of the ports) it'll sound good without risking damage to the speakers.
                            2005 Subaru Legacy GT
                            Status: 40% - starting install

                            AMD Sempron 3100, Biostar K8NHA PRO mobo, 512 meg DDR, WD 200 gig SATA, Opus 150, Xenarc
                            JBL GTi 6.5 fr, JBL 5.25 rr, (3) JBL 75x2 & 1 1200x1 amps, PA MOFO 12 sub

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                            • #15
                              :-D woohoo that was helpful lol its 9 30 in la right now im going to guitar center at like 11 30 and buying 4 speakers and 2 amps :-P two jbl jrx 12 and 2 crown xls 602 amps ;-) each speaker is rated 2000 watts peek and each amp is rated 1600 watts mono! haha

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