Jeffdachef
5,000+ posts
Gunz That Turn on Nunz
Need to know your dimensions(depth x width x height) and sub you are using.
fasfocus00
5,000+ posts
doITdaWHITEwayORdoITtwice
seriously man, pi * r * r
- Thread Starter
- #4
11x15x13 hds208 with a cm1 amp I understand the pi deal but it doesnt make sense to me..i am trying to tune to 32hz with calculations from various web calculators using my 2" flared aero port from parts express it calculates it should be 9.14 inches long, but how much volume of the enclosure is the port taking up?
3.142×2×2×9.14
- Thread Starter
- #7
thank you sir I appreciate your help I am reconfiguring 13x16.75x11 external size, sub displacement of .06 and 2"x8.32 aero port (.06 displacement), that should give me a final volume of .85 after all displacements I think
Jeffdachef
5,000+ posts
Gunz That Turn on Nunz
Torres' Box Tuning Calculator - Updated 8/18 - Subwoofers / Enclosures - SMD Forum
download this program and plug in numbers. There's tutorials on how to use it properly on that site too.
Buy a pvc pipe from home depot, its a lot cheaper and you can always remove it and try out different tuning to see what you like. Flares are easy to do since its only a 2/3 inch port, get a metal ladle, put it over the kitchen stove top upside down and heat it up, let the pvc heat up and start flaring out.
You do need a lot more port area than a single 2 inch aero.
- Thread Starter
- #9
hmm I am lost then on a .85 enclosure I am looking to get down to 32 all of the beginner calculators are pointing towards around 8.324inches in length ..what am i doing wrong
- Thread Starter
- #10
Jeffdachef
5,000+ posts
Gunz That Turn on Nunz
you see that little spot where it says port area per foot? needs to be 9 - 13(soundqubed subs are designed to work better with a lot more port area so keep iit on the higher side, go with 13). At 3.57 you are choking out the subwoofer which results in loss of output and horrible sound quality due to port noise.
- Thread Starter
- #13
how the hell do i do this then..good thing I didnt start production yet..is there an easy way to explain the port area per foot?
Jeffdachef
5,000+ posts
Gunz That Turn on Nunz
Calculate your square inches of port area so for example a 6 diameter port would be radius^2xPI (3x3x3.14) which is 28.26 square inches of port area. lets say your enclosure is 2.5 cubic feet AFTER port/sub/bracing displacement. you divide 28.26 by 2.5 = 11.304 sq inches of port per cubic foot. (another note: Most of these websites use the cubic feet BEFORE sub/port/bracing to calculate the length of the port which is completely WRONG, they assume you know to subtract all the sub/port/bracing displacements before using the online calculator)
Generally slot ports require 12-16 for that value and for aeroports, you can get away with 9-13 port per foot. The more Xmax your subwoofer has, the more port per foot its going to want since it will be moving a lot more air through high excursion. (some crazy competition subs are an exception to these general rules)
The number you have right now will cause a lot of port noise which is a nasty chuffing noise from bottle necked airflow though a tiny port. Results are bad sound quality, greatly reduced output and annoying noise.
Also with aeroports, you'd want one bigger one rather than 2/3/4 smaller ones to keep high efficiency.
Just change the numbers around for the port diameter until you land in the acceptable range.
Just be glad you have a software to auto calculate everything, people used to do all the math by pen and paper.
Radius of a 2" port is 1 so its 1x1x3.14 = 3.14
what you are doing is for a 4 inch port, however the math is incorrect too 3.14 x 2 x 2 = 12.56
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