beanbo12 Posted August 11, 2015 Report Share Posted August 11, 2015 Iv decide to design a box for 2 sound integrity ht18's. The plane is 11 cbft @ 32 Hz With 160 sq inches of port. My port size internal dimensions are 4 x 39.5 x 27.5 long( the 27.5 is the length according to 12volt.com please correct me if I'm wrong). I want to fold the port to keep the box the less depth as I can so I still have some room in the trunk of my 2001 suv explorer. Q: The internal port (4x39.5x27.5) comes out to be 2.514 cubic feet, when I fold the port keeping it the same width (4") do I try to keep the same cubic feet of the port as if it was straight to keep the same tuning. I know the length changes when you fold the port I'm just want to make sure I'm going the right direction. thank you Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted August 11, 2015 Report Share Posted August 11, 2015 The volume the port take up doesn't matter, what matters is the length of the port measured down the center. As long as you keep that at 27.5" your tuning should remain the same. A port that is 4" x 39.5" has a pretty high aspect ratio (almost 10:1). High aspect ratio ports aren't the most efficient. How much power are you going to be putting to these subs? "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...
beanbo12 Posted August 11, 2015 Author Report Share Posted August 11, 2015 I have a Ss rubi 1600.1 for right now but will upgrade to a solid 2k eventually. The box I want to build is going to basically look like a truck tool box because the back of my explorer has a hump on each side measuaring 6" high by 5" wide. By using some of the bottom portion as the port I can build the top piece bigger to accomadate volume for the subs. What would be a more effecient size port or ratio for the box? Link to comment Share on other sites More sharing options...
beanbo12 Posted August 11, 2015 Author Report Share Posted August 11, 2015 Uh ok I get where your getting the 10:1 port ratio. 39.5/4= 9.875. So by decreasing the port ratio let's say 5:1 or 3:1 the more efficient the port. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted August 11, 2015 Report Share Posted August 11, 2015 Yup, you got it. You could orient the port vertically, which will let you have a lower aspect ratio. "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...
beanbo12 Posted August 11, 2015 Author Report Share Posted August 11, 2015 If I port it vertically I would have to split the port at the end one going left and the other right to keep the depth shorter. Just and exp. Say my port is 8 by 20 and 27.5 length and my box is 20 deep. Staying on center line from the front of the box back would be 16(1/2 of port - d 20) would I then just subtract 27.5 from 16= 11.5 and then dived that in 1/2 = 5.75 and add to each side of the center line 16 to keep the same tuning. 16 +5.75+5.75=27.5. Sorry I'm not the best at explaining this try to bare with me. Also will having the subs close to the port cause more turbulance or I guess I would say loading issues on the port. (port noise etc.) Link to comment Share on other sites More sharing options...
beanbo12 Posted August 11, 2015 Author Report Share Posted August 11, 2015 Bumpski Link to comment Share on other sites More sharing options...
ChevyBoy95 Posted August 11, 2015 Report Share Posted August 11, 2015 Here is the whole inefficiency/port ratio deal.... say you have a 100 sq in of port and 12" long. Option 1: (1:1) 10" x 10" opening 12" deep.... which would be 4 10" x 12" internal surface areas for a total of 480 sq in of inner port surface area, along with a perimeter of 40". Option 2: (100:1) 1" x 100" opening 12" deep... which would be 2 100" x 12" internal surface areas and 2 1" x 12" internal surface areas for a total of 2424 sq in of inner port surface area, along with a perimeter of 202" See the difference, more surface area equates to more drag aka inefficiency, in theory and generally in practice. Best Score to Date : 160.5 dB Outlaw (47Hz)[4 XM 15's & 2 Taramps Bass 12k's] BL : http://www.stevemeadedesigns.com/board/topic/147800-chevyboy95s-4-15s-7krms-wall-1533-db-on-half-power/YouTube: http://www.youtube.com/hitemwiththeflex/ Link to comment Share on other sites More sharing options...
beanbo12 Posted August 11, 2015 Author Report Share Posted August 11, 2015 Thanks for the info on the port ratio. Still trying to figure out how to split the port in the back of the sub box. Seems that all the side port extensions are a smaller port width then the port width from front to back. Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted August 11, 2015 Report Share Posted August 11, 2015 Yup, that's right. If your port is 5" wide before it gets to the back, it would be 2.5" wide going to either side. That way your total port area remains the same. "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...
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