Sheena Posted December 28, 2011 Author Report Share Posted December 28, 2011 could you give me an example on how to get the proper port volume? 14" tall 3.5" wide 32" long displaces how many cu ft? in torres you agreed on 1.04 cu ft, but my question is, what were the calculations to get there, i spent a few good hours guessing on how you got it, but i never found out :/ and the box is 20.25" deep 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
Sheena Posted December 28, 2011 Author Report Share Posted December 28, 2011 what i did.. and i got 1.05 cu ft.. is.. 14*3.5*32 = 1,568 20.25-1.5-1.75 = 17" (this is how long the port is, leaving 1.75" in the back) 17*14*.75*.75 = 133.875 7.5*14*.75*.75 = 59.0625 59.0625*2 = 118.125 (at this point i have no idea wtf im doing, im literally just guessing. to get 7.5 i halved the port width in the back because this is a separate chamber box, so 3.5"/2 = 1.75") 1,568+133.875+118.125 = 1.05324074 cubic feet 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
Joe X Posted December 28, 2011 Report Share Posted December 28, 2011 Ok just take the physical port length that Torres lists = 27.75 so two pieces of wood installed in an L shape will need to have that length, therefore: L1 + 0.75 + L2 = 27.75 in Since I only care about the length of the pieces of wood I solve for L1 + L2 L1 + L2 = 27.0 And then I calculate the volume of both parts together: 14 x 0.75 x 27 = 283.5 cubic inches. That's for the wood displacement, for the airspace displacement you take the 32 and take away 0.75 which is not part of the internal volume: 14 x 3.5 x 31.25 = 1531.25 cubic inches. Adding both displacements together = 1814.75 or 1.0502025 cubic feet. Quite frankly I couldn't figure out how Torres came out with the 1.2 cubic feet. Link to comment Share on other sites More sharing options...
getlocivic Posted December 28, 2011 Report Share Posted December 28, 2011 wouldnt that freak you out when u wake up and your ride is gone... frankly i dont care what the excuse is,, id never let some1 "take" or borrow my car.. learned the hard way on that 1.. also i run 2 skar vvx 12s in 4 cubes net with 16per cube tuned loww.. and they freaking love it..they laugh at my saz 1500 at 1/2 ohm too.. you should be very happy with thtem Link to comment Share on other sites More sharing options...
Sheena Posted December 28, 2011 Author Report Share Posted December 28, 2011 wouldnt that freak you out when u wake up and your ride is gone... frankly i dont care what the excuse is,, id never let some1 "take" or borrow my car.. learned the hard way on that 1.. also i run 2 skar vvx 12s in 4 cubes net with 16per cube tuned loww.. and they freaking love it..they laugh at my saz 1500 at 1/2 ohm too.. you should be very happy with thtem they are already installed in a 3.78 cu ft @ 32 box.. but with 10.99 sq in of port per foot, so anything under 32 and they choke HARD, it sounds like im play in a 20 hz note when it hits a 28 hz one lol. so i'll be correcting that with this new box and getting rid of some loading issues for one of the subs. originally this box was for a pair of jh 55-12 04's (mtx 400wrms 4 SVC) and honestly, i had them both for about 2 years, ran clipped music to them, clipped signal, clipped everything and the coils wernt all that bad imo. well its my dad that took it, wasnt like a friend or a girlfriend, and he took it up the road to get it inspected. i thought it was nice of him 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
Sheena Posted December 28, 2011 Author Report Share Posted December 28, 2011 Ok just take the physical port length that Torres lists = 27.75 so two pieces of wood installed in an L shape will need to have that length, therefore: L1 + 0.75 + L2 = 27.75 in Since I only care about the length of the pieces of wood I solve for L1 + L2 L1 + L2 = 27.0 And then I calculate the volume of both parts together: 14 x 0.75 x 27 = 283.5 cubic inches. That's for the wood displacement, for the airspace displacement you take the 32 and take away 0.75 which is not part of the internal volume: 14 x 3.5 x 31.25 = 1531.25 cubic inches. Adding both displacements together = 1814.75 or 1.0502025 cubic feet. Quite frankly I couldn't figure out how Torres came out with the 1.2 cubic feet. thanks for this, and thanks for being an understanding guy :] explained very well. i know i said i'd start the box build, but christmas came by and i was left with a few extra $, so i went a bought a HU. (ive been running a stock one off a line level converter) 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
Torres Posted December 28, 2011 Report Share Posted December 28, 2011 im not sure what the calculations are on this type of box.. but did you take them into account? this will be the type of box that will be built, because a typical slot port (3 common walls) with a 33" long port creates some nice loading issues. (correct me if im wrong) that would be 2 common port walls for future reference Ok just take the physical port length that Torres lists = 27.75 so two pieces of wood installed in an L shape will need to have that length, therefore: L1 + 0.75 + L2 = 27.75 in Since I only care about the length of the pieces of wood I solve for L1 + L2 L1 + L2 = 27.0 And then I calculate the volume of both parts together: 14 x 0.75 x 27 = 283.5 cubic inches. That's for the wood displacement, for the airspace displacement you take the 32 and take away 0.75 which is not part of the internal volume: 14 x 3.5 x 31.25 = 1531.25 cubic inches. Adding both displacements together = 1814.75 or 1.0502025 cubic feet. Quite frankly I couldn't figure out how Torres came out with the 1.2 cubic feet. there may have been a miscalculation that has since been fixed, but i did notice that you did not calculate end correction into the equation for port displacement. it will be a very minute, probably inaudible difference. but still a difference regardless Link to comment Share on other sites More sharing options...
Sheena Posted December 28, 2011 Author Report Share Posted December 28, 2011 i know the picture posted was 2 common walls, but i was saying a typical box/most common/most used which is 3 common walls. would love to know where the fixed miscalculation program is ;x 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
Joe X Posted December 29, 2011 Report Share Posted December 29, 2011 Hi, Torres, I have read that the volume belonging to the end correction length also belong to the port not to Vb but I have found no actual research documents supporting those claims. If you think about it, there are friction and turbulence losses mostly in the port turn, which are different with a wedged corner but if you see the JL Audio document referenced above those are not accounted for, just keep below the 9:1 ratio rule. Regardless of the insignificant effects of the displacement you mention I would love to see some document that may exist regarding that if you know of one. Link to comment Share on other sites More sharing options...
Sheena Posted January 4, 2012 Author Report Share Posted January 4, 2012 Today i'll be getting my kenwood-X395, so i'll post pics when it arrives. i still need to buy the dash kit and the antenna adapter (i already have the harness). probably order those today. box is still on hold due to my dad being sick, and we build these things together. 09 Civic EX KDC-X395 (2) SKAR Audio VVX-12 Skar Audio SK-1500.1 4 cu ft @32 (new box and more port soon) Firing Forward not sealed off Stock 80 Amp Alt Big 3 In 1/0 Knu 2 Runs To The Back 1 Pos 1 Neg In 1/0 Knu DD-1'd 13.8v drop Link to comment Share on other sites More sharing options...
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