General Discussion General discussion about all things car audio, from pioneer, orion, alpine and eclipse.

quick port question

Old 06-11-2006, 11:33 AM
50 Watt CAFz'r
Thread Starter
Join Date: Mar 2003
Posts: 191
quick port question

for one 15 what would be better one single 4 inch port or 2 3 inch?
kirk tarrant is offline  
Old 06-11-2006, 07:31 PM
50 Watt CAFz'r
iTrader: (1)
Join Date: Jul 2002
Posts: 399
IMO I think you'll need more port area...a slot type port would be easier to fit a bigger port.

But to be sure, there are a couple of factors that determine the necessary port area. i.e. What sub? Size of enclosure? Tuning? Power?
gleepoy is offline  
Old 06-11-2006, 09:07 PM
500 Watt CAFz'r
GrizZz's Avatar
Join Date: Apr 2004
Posts: 756
I dunno a lot about boxes, but from what I do know, you're gonna want two 6in. ports or four 4in. ports.

The big SPL boys are running that kind of setup...

And I just built a new SQ box, with dual four's. They're so long, they're half an inch from the sub basket.

She's tuned to 31hz.

GrizZz is offline  
Old 06-11-2006, 11:33 PM
Dukk's Avatar
Join Date: Feb 2006
Posts: 16,855

I vote (2) 4" diameter vents or more.
Dukk is offline  
Old 06-11-2006, 11:58 PM
50 Watt CAFz'r
xxPunk0Ramaxx's Avatar
Join Date: Nov 2004
Posts: 167
pretty hard to say without knowing what speaker it is.

you can also use the more traditional way to determine the minimum port diameter.

Sd = pi*(D/100)^2/4
Vd = Sd*Xmax/1000
MinimumDiameter= 100*(20.3*(Vd^2/Fb)^0.25)/Np^.5

this is with xmax in mm, diameter in cm, Fb=resonant (tuning) frequency of port, and Np=number of ports you will use.

Last edited by xxPunk0Ramaxx; 06-14-2006 at 09:55 PM.
xxPunk0Ramaxx is offline  
Related Topics
Thread Starter
Last Post
Enclosure Design & Construction Help
05-05-2014 01:11 AM
Enclosure Design & Construction Help
08-27-2004 01:13 PM
Enclosure Design & Construction Help
07-02-2004 07:44 PM
General Discussion
06-15-2004 12:34 AM
Install related
10-15-2003 09:34 AM

Thread Tools
Search this Thread
Quick Reply: quick port question

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to and affiliated sites.