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debutis
07-03-2003, 10:14 PM
Well, I finished the box today and now it's all sealed up... Now I need to know the port diameter and length of the port that I need to have to tune my 5.994 cubic foot box to about 30hz. What will I need to do??
Thanks in advance

MikeofTulsa
07-03-2003, 10:54 PM
slot or round port?????


not sure on the slot port....but i got 6.27968" long x 4" round for a round port

debutis
07-03-2003, 10:59 PM
thats exactly what i needed! Thanks

paikiah
07-03-2003, 10:59 PM
do you mean to say that you're fine with any diameter of round port(s), or slot port size?

debutis
07-03-2003, 11:00 PM
would like a large diameter round port so less port noise.. just need it tuned to 30hz tho

MikeofTulsa
07-04-2003, 02:40 AM
figured so...thats why i went w/ 4" diameter

debutis
07-04-2003, 04:38 AM
Ok, now that I have the info on how to tune it to 30hz.. what dimensions on the 4" port do I need to raise the tuning to about 48hz for comps?? Where can I buy removable/swapable ports??

paikiah
07-04-2003, 05:01 AM
If you remove the port and put in another one, the net volume will change.

DO be aware :)

debutis
07-04-2003, 05:03 AM
Ok.. I still need the length of a 4" diameter port that will give me a tuning of 48hz.

paikiah
07-04-2003, 05:09 AM
TO be honest, I dunno how he came up with 6"+ length...

i input the data onto winISD (5.994cubes @30Hz) and came up with 3.32" length with a 4" diameter port.


with the vents tuned to 48Hz, you might as well not put a tube in there, cause winISD says it's too short. The thickness of the wood would already be the peak figure.

debutis
07-04-2003, 11:17 AM
hmmm can anyone confirm either of the final port lengths?? Is there any way I can run 2 ports?? Is there any website that gives nice detailed info about how to port a box with pvc? I'm not really sure how to mount the pvc to the box.. Does the port stop at the inside edge of the box or does it extend to the furthest post outside of the box??

paikiah
07-04-2003, 11:43 AM
Originally posted by debutis
hmmm can anyone confirm either of the final port lengths?? Is there any way I can run 2 ports?? Is there any website that gives nice detailed info about how to port a box with pvc? I'm not really sure how to mount the pvc to the box.. Does the port stop at the inside edge of the box or does it extend to the furthest post outside of the box??


You can go the old-fashioned and accurate way by calculating port length manually. Search for it and you will find it. It's been talked about recently.

As for the ports, it doesn't matter if the ports are inside or out. It will depend on whether you calculated port displacement into the box or not. Heck, a 50" port requirement CAN be outside of the box, but it won't look too good unless you are ULTRA-creative.

debutis
07-04-2003, 12:16 PM
so basically from port end to port end, is the port.. So this means I could have half inside and halfoutside?? Just so long as the port is connected to the box?? However, I need to take into acount all the air inside of the port to figure out tuning due to the port and it's volume taking up space?? How do people usually attach their pvc port to the box itself??

paikiah
07-04-2003, 12:20 PM
i think you've got the right idea. The volume of the port does not contribute to the volume of the box.

How to attach? Usually silicone. If the port is relatively long or has bent pipes with elbows, some choose to have braces that also hold up pots. It needs a bit more accuracy in calculations and wood-cutting, but shouldn't be anything at the "Einstein" level.:)

debutis
07-04-2003, 12:52 PM
Hmm I still need someone to verify my port length however.. I tried the equation and somehow must have messed up because I came out with 16.472.. Wether thats in inches or cm i'm not really sure... If it is infact cm, then I got right about 6.48 inches.. Thats not taking into account the volume of the port however.. How do I figure that in???

debutis
07-04-2003, 12:57 PM
when attaching the port, dont people use some sort of flange or something?? I mean, if you have a 4" port diameter, and you cut your hole to be 4.2", you've just made the hole to big and now the pvc just slides right through the hole... How do they connect it to the box?? They cant just hope the pvc fits in there nice and tight..

paikiah
07-04-2003, 01:04 PM
There are those who swear by reduced port noise with aeroports.

As for attaching the PVC to the box, unless you have a better idea, mine is simple silisone. Just makin sure that the hole is as tight as possible. Or you ucould mesh up some MDF and wood glue togehter, then apply it like silisone. I'm sure it will be more rigid than silicone alone.


If you do use a flange or mouthpiece, you can screw the mouth of the port itself onto the box (like how so many has been done here)

:)