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View Full Version : where do i place the port??



95Prober
01-03-2005, 12:29 PM
hi. i have subs that ask for a sealed enclosure of 0.7 cuft. i am going to experiment on making a sealed and ported box then decideing on which one is better. it may my a waste of wood, but im new at this so i wanna at least try. now my first question is, if i went up to 1.0 cu.ft in stead of the 0.7 just for the sake of it , would it make a diference? the rason i ask is becasue i see a lot of people just using 1.0 cu.ft boxes. would it matter? also, i plan to make my boxes seperated to give each sub its own space. now i think the sealed is pretty straight foward to build, but if when i make the ported one of the same size, whichever size i choose, where would i decide to place the port , on the front besside the sub, on top top, etc. and at what lenth and diameter?? here are the subs i have :

http://pioneerelectronics.com/pna/product/detail/0,,2076_4061_37598_tab=B,00.html?compName=PNA_Prod uctDetailComponent

and here is the specs , you have to scroll down the page:
http://www.caraudio.com/vb/showthread.php?t=19817&highlight=TS-W1041DVC

any help would be great!!!

squeak9798
01-03-2005, 12:45 PM
now my first question is, if i went up to 1.0 cu.ft in stead of the 0.7 just for the sake of it , would it make a diference? the rason i ask is becasue i see a lot of people just using 1.0 cu.ft boxes. would it matter?

Well, yes and maybe no :) Yes, the larger box will make a difference in the responce and resonance of the system (because it affects what is called the Qtc (http://www.carstereo.com/help/Articles.cfm?id=29) ).......but this change may or may not be audible (atleast not audible to you). Best way to get a general idea of the difference is to pop it into a box program and look at the changes in the response curve and group delay.


but if when i make the ported one of the same size, whichever size i choose, where would i decide to place the port , on the front besside the sub, on top top, etc. and at what lenth and diameter?? here are the subs i have

Well, generally ported boxes need to be bigger than sealed box....so I hope you weren't talking about making the ported box the same size as the sealed. Generally you want to put the port on the same side as the subwoofer. General rule of thumb is that the port needs to be atleast half it's diameter away from the sub (IIRC). So, just don't put the port RIGHT next to the sub and you'll be OK.

As for lenght and diameter.....for port diameter I would use around 3" to 4"....or you could try using a slot (rectangular) port. And the length is going to depend upon 1) The internal volume of the box, 2) The port's diameter (or cross-sectional area) and 3) The frequency you want to tune to.