a_steezy Posted January 17, 2009 Report Share Posted January 17, 2009 so i got in some new subs... four memphis pr 12's, i need some help on the port size/depth, i'm clueless here box will be 44"x24"x15 roughly 9ft^3 before anything, i'm aiming for subs up, port back (pic) i kinda wanna do a port in the center like steve so it works inbetween the subs, doesn't have to, we can go under the subs also with a wide port roughly how much port area should i go for the four 12's? i'm aiming for 32-34hz, i'll go a lil over Quote '98 Dodge Durango 5.9L 5% front windows, 2.5% on all backs Alpine CDA-9883 Kicker ZX350.4 Kicker KS650's in all doors Kicker 1/0 hyperflex Link to comment Share on other sites More sharing options...
eliassami5 Posted January 18, 2009 Report Share Posted January 18, 2009 http://www.carstereo.com/help/Articles.cfm?id=31 input your dimensions and it tells you your port size, i would do aero ports but you can do a slot port if ya want. I put in 9ft^3 with 4 4" round ports tuned to 32 hz and they will each have to be 11.77in long or 2 6" round ports at the same freq and they will have to be 12.15" long each or 6"x12" port tuned to 32 hz and it will have to be 8" long there are many different combo's, just play with it and see what works with your box. Oh and you might wanna learn how to work with google sketchup..makes your life much easier. Quote 91' Jeep Cherokee - The Heep Just Empty Every Pocket 96' Volvo 960 - The B◘x [sPL_4_U] HiFonics - Alpine Pioneer - Clarion Infinity - Kicker KnuKonceptz Link to comment Share on other sites More sharing options...
eliassami5 Posted January 18, 2009 Report Share Posted January 18, 2009 might look like this or this Quote 91' Jeep Cherokee - The Heep Just Empty Every Pocket 96' Volvo 960 - The B◘x [sPL_4_U] HiFonics - Alpine Pioneer - Clarion Infinity - Kicker KnuKonceptz Link to comment Share on other sites More sharing options...
Boon Posted January 18, 2009 Report Share Posted January 18, 2009 Don't put the port in the middle of the face. Unless you're moving a hell of a lot of air relative to the box size it makes it less effective, you have high pressure on the walls around the port but very low pressure at the actual port mouth. Quote 10.x volts fo' life! Link to comment Share on other sites More sharing options...
a_steezy Posted January 18, 2009 Author Report Share Posted January 18, 2009 Don't put the port in the middle of the face. Unless you're moving a hell of a lot of air relative to the box size it makes it less effective, you have high pressure on the walls around the port but very low pressure at the actual port mouth. why would that make a difference? does the placement really matter, the air is gonna move in and out regardless where the port is? 6"x12" port tuned to 32 hz and it will have to be 8" long and that is awesome, thanks alot, kinda with going with what's ahead, how would this be if it was facing back right inbetween the subs? i know the sub up port up isn't as great Quote '98 Dodge Durango 5.9L 5% front windows, 2.5% on all backs Alpine CDA-9883 Kicker ZX350.4 Kicker KS650's in all doors Kicker 1/0 hyperflex Link to comment Share on other sites More sharing options...
a_steezy Posted January 19, 2009 Author Report Share Posted January 19, 2009 ttt Don't put the port in the middle of the face. Unless you're moving a hell of a lot of air relative to the box size it makes it less effective, you have high pressure on the walls around the port but very low pressure at the actual port mouth. any other opinions on this? if not box is being built tomorrow with sub in the middle Quote '98 Dodge Durango 5.9L 5% front windows, 2.5% on all backs Alpine CDA-9883 Kicker ZX350.4 Kicker KS650's in all doors Kicker 1/0 hyperflex Link to comment Share on other sites More sharing options...
Boon Posted January 19, 2009 Report Share Posted January 19, 2009 why would that make a difference? does the placement really matter, the air is gonna move in and out regardless where the port is? Think about the pressure (actually pressure variation but hey...) inside your box. It's going to be highest in the corners because that's where the waves meet. In terms of on-face pressure it's going to be lowest in the middle of the face unless you have some funky design directing the pressure. Unless your box is really small relative to the displacement of the cones moving it's more efficient to have it on an edge. There's some technical BS like laminar airflow but I won't go into it. Suffice to say that the exact same box metered very differently when we moved the port from the middle of the face to the bottom of it. Quote 10.x volts fo' life! Link to comment Share on other sites More sharing options...
eliassami5 Posted January 19, 2009 Report Share Posted January 19, 2009 (edited) moved the port to the bottom and added 45s on the corners and some dowel supports here are some dimensions: oh and the port it 8" deep Edited January 19, 2009 by eliassami5 Quote 91' Jeep Cherokee - The Heep Just Empty Every Pocket 96' Volvo 960 - The B◘x [sPL_4_U] HiFonics - Alpine Pioneer - Clarion Infinity - Kicker KnuKonceptz Link to comment Share on other sites More sharing options...
m4a3master Posted January 25, 2009 Report Share Posted January 25, 2009 (edited) What about Port Area? 9ft^3 of volume, and 4 12's? Wouldn't he need 12-16 square inches per 1ft^3 of volume? ... thats like 108-144 square inches of port area needed. Edited January 25, 2009 by m4a3master Quote Link to comment Share on other sites More sharing options...
IAMBUMP Posted January 25, 2009 Report Share Posted January 25, 2009 not to highjack your thread, but does anyone have the equation for port length if you have port area and all? Quote If you've been doing something for 20 years, does that mean what you do it right??? __________________________________ Want: 2x Phoenix Gold RSD65CS Comp Amp Undecided AA Havoc AQ 1200 knu wiring set scew lugs for all connections Alpine IDA-X303 2v preout --this goes under the seat. Have: Alpine tape deck w/ Benzi Box and 6 disc changer Check out my Toyota build Link to comment Share on other sites More sharing options...
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