Ludachris5150 Posted September 9, 2012 Report Share Posted September 9, 2012 I have 2 4" Precision ports laying around from PE. Their the full length that they came, Thinking about building a 2nd box tuned to 28hz just to use them and see how I like it. Question I have is, Is it possible to get a tune of 28hz with just the 2? More important is that enough port area? Oh yea subs are 2 12" sa12s, Going in an suv so the box could be pretty damn big Rebuild in progress... Link to comment Share on other sites More sharing options...
Jessica Posted September 9, 2012 Report Share Posted September 9, 2012 From what i've been told you need 3 4" aero's to get enough port area, you want 9 -12 sqin/ft for round ports. And their total length is like 18.5 so i think the lowest you can tune and still have enough airspace for the subs is around 33-34 hz with those ports. Maybe someone with more knowledge has better info. Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
certifiednut Posted September 9, 2012 Report Share Posted September 9, 2012 their total length is 18 but once you figure the flares length in, the useable length is 17 inches these orphans aren't going to feast on themselves Link to comment Share on other sites More sharing options...
Jessica Posted September 9, 2012 Report Share Posted September 9, 2012 their total length is 18 but once you figure the flares length in, the useable length is 17 inches They are 18.5", i have one right next to me here. The spec sheet is wrong. Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
certifiednut Posted September 9, 2012 Report Share Posted September 9, 2012 their total length is 18 but once you figure the flares length in, the useable length is 17 inches They are 18.5", i have one right next to me here. The spec sheet is wrong. yours may measure 18.5 but the 4 i have here measure 18. but that doesn't really matter, you subtract 1 inch off of total length to get the length you need, so if you need 17in. you would want a 18in port total length. for precision ports anyways. these orphans aren't going to feast on themselves Link to comment Share on other sites More sharing options...
Joe X Posted September 9, 2012 Report Share Posted September 9, 2012 I have 2 4" Precision ports laying around from PE. Their the full length that they came, Thinking about building a 2nd box tuned to 28hz just to use them and see how I like it. Question I have is, Is it possible to get a tune of 28hz with just the 2? More important is that enough port area? Oh yea subs are 2 12" sa12s, Going in an suv so the box could be pretty damn big It is possible to use them, a 4 cubes enclosure with two 4" ports will tune to 28.3Hz, if it is going to be enough port area or not depends on power you are giving, if you are only giving rated is likely that you will only experience some efficiency loss. It's good to have a lot of space to work with but the size of the box is related to the subs. I would recommend a slot port if you are going to drive them above rated, if you want a box drawn for you post your max dims and model of your amp and SUV. @strangeduck: A fraction of the flare length does not belong to the port, the manufacturer determines by tests which is the effective length of the flared port, I guess the only way to prove them wrong is to install it properly and see where it tunes. Link to comment Share on other sites More sharing options...
Jessica Posted September 9, 2012 Report Share Posted September 9, 2012 So much for the precision part lol. My tubes must be cut longer for some reason. Rest in peace, walled 87 accord build log 03' Corolla build with AA Mayhem inside. My super random youtube channel and terrible camera work. Wiring comparison by CaptainzPlanetz Wire and fuse guide by Guest SyKo13 Link to comment Share on other sites More sharing options...
Ludachris5150 Posted September 9, 2012 Author Report Share Posted September 9, 2012 I have 2 4" Precision ports laying around from PE. Their the full length that they came, Thinking about building a 2nd box tuned to 28hz just to use them and see how I like it. Question I have is, Is it possible to get a tune of 28hz with just the 2? More important is that enough port area? Oh yea subs are 2 12" sa12s, Going in an suv so the box could be pretty damn big It is possible to use them, a 4 cubes enclosure with two 4" ports will tune to 28.3Hz, if it is going to be enough port area or not depends on power you are giving, if you are only giving rated is likely that you will only experience some efficiency loss. It's good to have a lot of space to work with but the size of the box is related to the subs. I would recommend a slot port if you are going to drive them above rated, if you want a box drawn for you post your max dims and model of your amp and SUV. @strangeduck: A fraction of the flare length does not belong to the port, the manufacturer determines by tests which is the effective length of the flared port, I guess the only way to prove them wrong is to install it properly and see where it tunes. Well Im going to be running them off a crescendo bc2k. Right now my box is about 3.8 cubes, 32hz... Its a slot port, And it sounded ok in my cadillac but it was built for that car not my current, Its port and subs back. Just wanted to tune a little lower, And I was going to try a subs up port back box. Not competing, Just want to smash the lows. Im pry only going to run somewhere around 8-900 watts per sub so a 4 cube box is pry to big? Then again the box I have now may be to big Rebuild in progress... Link to comment Share on other sites More sharing options...
Ludachris5150 Posted September 10, 2012 Author Report Share Posted September 10, 2012 I can post my max dems tomorrow tho Rebuild in progress... Link to comment Share on other sites More sharing options...
bkolfo4 Posted September 10, 2012 Report Share Posted September 10, 2012 The great 12" challenge a few years ago was done using a box with a single 4" aero. One of the subs was a 12" BTL with several thousand watts. Put up some really good numbers with that single 4" aero. . . Current system: 1997 Blazer - (4) Customer Fi NEO subs with (8) American Bass Elite 2800.1s Previous systems: 2000 Suburban - (4) BTL 15's and (4) IA 40.1's = 157.7 dB at 37 Hz. 1992 Astro Van - (6) BTL 15's and (6) IA 40.1's = 159.7 dB at 43 Hz. Link to comment Share on other sites More sharing options...
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