lilrezy50 Posted July 2, 2017 Report Share Posted July 2, 2017 I am wondering if someone would be willing to check my math on this enclosure for 2 sa 12's 14.25" h 30.25w 12" depth 1 15" depth 2 (wedge enclosure) 3/4" material = 2.55 ^3ft internal air space Sa's will displace .28^3 leaving 2.77^3 To achieve 35hz tuning, aero port will be 4" diameter by 9.25" long port displacement V = radius x pi x length = 4^3 x pi = 50.26 x 9.25 = 464.9 ( 465 cubic inches) - converted to .269 cubic feet rounded to .27 so remaining displacement of 2.77 will end up being 2.0^3 after port displacement Link to comment Share on other sites More sharing options...
Jessica Posted July 2, 2017 Report Share Posted July 2, 2017 1 4" aero is not enough. try 3 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...
Jessica Posted July 2, 2017 Report Share Posted July 2, 2017 i ran 4 sa'12's in 9cuft with 126" of port area. it was pretty nasty. 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...
lilrezy50 Posted July 2, 2017 Author Report Share Posted July 2, 2017 I might consider that, but how does that math look Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted July 2, 2017 Report Share Posted July 2, 2017 I get 2.21 cu ft net after sub and port displacements. That's too small for a pair of SA-12s and like strangeduck said, no where near enough port area. Here is a port area calculator to help you get a better idea how much port area you should have: https://goo.gl/STAv4p "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
lilrezy50 Posted July 2, 2017 Author Report Share Posted July 2, 2017 What I am thinking is a new design that is 4.243 net volume 3.96 cubes after woofers I need at least an 8" port for 50 cubic inches roughly as my minimum port area is 47 with 1600watts, and tuned to 35 My question is, if I have 3.96 cubes to work with, an 8 inch port internally will take up 22 inches and displace too much can I mount two 4 inch aeros internally to make that 8" area up? they will only be roughly 4 inches long and take .11 cubes of displacement each leaving 1.87 cubes per woofer or I can mount the 4 inches externally to leave 1.98 per woofer Link to comment Share on other sites More sharing options...
Jessica Posted July 2, 2017 Report Share Posted July 2, 2017 Two 4" ports is not the same as 8". I'm going to ask you to find the area of a circle. Once you know how to do that you can figure out to achieve your port area 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...
lilrezy50 Posted July 2, 2017 Author Report Share Posted July 2, 2017 Area = pi * r^2 so 8" port = 16 sq in * pi = 50.26 sq in Link to comment Share on other sites More sharing options...
lilrezy50 Posted July 2, 2017 Author Report Share Posted July 2, 2017 I see as well, 4" port = 4 sq inh * pi = 12.56 x2 = 25.12 sq in for both ports where as 50.26 for the single 8 inch Link to comment Share on other sites More sharing options...
lilrezy50 Posted July 2, 2017 Author Report Share Posted July 2, 2017 Here is where I think I land best Height 14.25 Width 30.25 Depth1 22 Depth2 25 4.66 cubic feet = 4.38 after sub displacement (.28) Port Diameter (D) 8 Box Volume (Vb) 4.38 Tuning Frequency (Fb) 35hz Port Length 19.4 Pi(r)^2(height)/1728 3.14 * 16x19.4 = .56 displacement 4.38 - .56 = 3.82 = 1.91 per woofer How does that look? Link to comment Share on other sites More sharing options...
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