TRON Posted June 25, 2014 Author Report Share Posted June 25, 2014 I can't even recreate your number of 185 with multiple different attempts. Either way, the math was wrong and you're severely under on port area. Ports are actually 5 inches long. Okay: Volume of a cylinder = (pieR^2)H. So (3.14 x 2)^2 x 5 = 62.8 cuin. 62.8 x 3 = 188.4 cuin. This is where I'm totally confused now: I've never built enclosures using "port area" as my guideline, software tells me the size to make it. So when you describe port area, you literal mean the surface area and not the volume of the port? So if I do the math for the surface area: 2(pie)RH + 2(pie)R^2 I get about 87.9 for one so a total of 263 sqin. So too much port in that case. Avalanche Alpine Type S comps Alpine Type S 10'' Alpine MPR-F300 Alpine MRX-M50 Mechamn 270 XS Power d3400s Link to comment Share on other sites More sharing options...
k3n12ock Posted June 25, 2014 Report Share Posted June 25, 2014 Not enough port! You need at least 4 6" ports or 2 8" ports for 18s! That's just from experience. I cant tell you where the port area is though since I'm dumb. 05 xB - (2) EVIL 18s - (2) BC3500s - NO WALL Channel 1: http://www.youtube.com/k3n12ock Channel 2: http://www.youtube.com/MrK3n12ock2 Link to comment Share on other sites More sharing options...
TRON Posted June 25, 2014 Author Report Share Posted June 25, 2014 Not enough port! You need at least 4 6" ports or 2 8" ports for 18s! That's just from experience. I cant tell you where the port area is though since I'm dumb. Google can do the math for you! I'm going to try both sealing it up and increasing the port area. Avalanche Alpine Type S comps Alpine Type S 10'' Alpine MPR-F300 Alpine MRX-M50 Mechamn 270 XS Power d3400s Link to comment Share on other sites More sharing options...
bigsausagepizza Posted June 25, 2014 Report Share Posted June 25, 2014 Port area = Surface area of the port exit 2^2 x pi is the area of one 4" port, you have 3 so 3*2^2*pi = 37.7 sq in. So one 4" port gives you ~12.6 sq in of port area, to get to 170-180 you'd need 14 of them. This is why everyone is telling you to go with a slot port, it will be much easier to get the necessary area than using 14 4" aeros. 2008 Subaru WRX STI K&N Typhoon Intake Invidia Polished Stainless 3" turbo back with cat Cobb Accessport Dyno tune from Kaizen Tuning 320awhp 330ft-lb awtq MTX 421D Sub amp American Bass SQ900 Highs/Mids amp Sundown Audio SD-2 10 D4 JL Audio XR653-CS 3-way Components 3sixty.2 Second Skin Damplifier Pro Custom fiberglass wheel well enclosure Transmission Line quasi-floor enclosure http://www.stevemeadedesigns.com/board/forum/13-member-rides-builds-show-off-your-whip-show-off-your-system/ Bill Fitzmaurice TLAH line-array hifi towers 9 Goldwood 4" mids (each) 12 Goldwood 1/2" tweeters (each) NAD 1020 Preamp MiniDSP 2x4 Balanced processor Thorens TD166mkII Turntable Hafler DH-200 Amplifier http://www.stevemeadedesigns.com/board/topic/192638-line-array-hifi-tower-build/ https://www.facebook.com/HolyMountainGlass Link to comment Share on other sites More sharing options...
TRON Posted June 25, 2014 Author Report Share Posted June 25, 2014 Port area = Surface area of the port exit 2^2 x pi is the area of one 4" port, you have 3 so 3*2^2*pi = 37.7 sq in. So one 4" port gives you ~12.6 sq in of port area, to get to 170-180 you'd need 14 of them. This is why everyone is telling you to go with a slot port, it will be much easier to get the necessary area than using 14 4" aeros. Okay, I misunderstood what "port area" meant then, scene is that a port is 3 dimensional like the enclosure so naturally I assumed surface area of a cylinder, not a circle. Avalanche Alpine Type S comps Alpine Type S 10'' Alpine MPR-F300 Alpine MRX-M50 Mechamn 270 XS Power d3400s Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted June 25, 2014 Report Share Posted June 25, 2014 Okay, I misunderstood what "port area" meant then, scene is that a port is 3 dimensional like the enclosure so naturally I assumed surface area of a cylinder, not a circle. Don't worry, you are hardly the first person you make this mistake. Let us know how things sound once you get the box sealed up. I imagine it will be a lot better. "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...
CleanSierra Posted June 25, 2014 Report Share Posted June 25, 2014 I was thinking about it and realized I don't want you simply to plug the ports up. If you've got 10 cubes in a sealed box, on that kind of power, I don't know hope the subs will like it. If you want to add something inside of the box to displace more air, like around 4 cubes, then do it. Otherwise, get yourself some big 6" ports and use 4 of them. Someone can help you with a design sure tart point to get you the right amount of port length to get you the tuning frequency you desire. Sorry I didn't lay the math out for you, I should have given you the formula port area. Port area is the cross sectional area of 2 dimensional space that the port opening occupies. Im not the one you want to try to troll. Just a fyi for you. Link to comment Share on other sites More sharing options...
DylanBunch Posted June 25, 2014 Report Share Posted June 25, 2014 i had 1 x 18 in 6.3cbft at 32hz with 90" of port and it played 25-45hz very well, kinda wish i shrunk the port more cause it was originally tuned to 35 with 100" of port. Aim for 12-12.5cbft with 170-180" of port at 30hz and i bet youll be happier, unless its just your truck?It may very well be my truck. What style of port did you use? Slot? I've got 3, 4" areo-ports. slot port 2006 Ford Explorer 2 Team AA/Sundown 15s 6th order Ct Sounds 7k 4 PRV Mr500 8s Rockford p1000-2 Team Subsonic Lows Link to comment Share on other sites More sharing options...
Robert8252 Posted June 25, 2014 Report Share Posted June 25, 2014 Just from the dozen boxes I've built now, if your port isn't 20-30 inches long to get the tuning you pick you don't have enough port area. Now, aero ports don't need this much for the same performance but thats my rule of thumbs. 2013 F150 Crew Cab Old Build Log Feedback 2013 F150 Equipment - Some Awesome Stereo Sound Making Stuff Link to comment Share on other sites More sharing options...
TRON Posted June 25, 2014 Author Report Share Posted June 25, 2014 So I took out the ports and plugged up the holes, definitely increased the frequency range but still sounds weak. I'm going to work up a design tonight and post it for feed back. It's sucks because almost all of my enclosures I've never done the port by the opening area and they turn out great. Avalanche Alpine Type S comps Alpine Type S 10'' Alpine MPR-F300 Alpine MRX-M50 Mechamn 270 XS Power d3400s Link to comment Share on other sites More sharing options...
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