Port Help :)

[ssh 924]

First time building ported enclosure, I would have someone build it but I'd cost too much to ship and sounds like a fun project, sorry Argent hmm, scratch that

the box volume is going to be 7.66cuft

I used the port calculator at 12volt,

port width: 30"

port height: 2"

port length: 13"

tuning: 33hz

I drew up this pic so that someone could tell me if "B" is part of the port length or what (p.s. picture is not in proportion to dimensions, just general.)

So would A+B=13" or is A 13" and B is?

Edited June 16, 2010 by stefanhinote

[NB50 206]

B would be part of the port length but you have to measure down the center of the port for port length. So in other words you can't just take A + B. Really it would be A + port width + wood thickness + B = port length.

[ssh 924]

thanks bromo

[NB50 206]

Just an easy visual for you of how the port length is measured.

When I say port width I meant the width of the port making the turn (I noticed you had 30" listed as your width.) So if the 30" was making the turn ( which I don't imagine it is) it would be 30", if the 2" was making the turn it would be 2".

A little tip you may want to reconfigure the port a little, a general rule is to keep a port ratio of 9 to 1 between your height and width other wise you could get some port noise.

[imhungnurnot 9]

DON'T BUILD THAT, YOU'RE BUILDING A DAMN WHISTLE.. LOL THATS ONLY 3.4 SQUARE INCHES OF PORT PER CUBEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

How many subs do you have? and what size?

[Duran 387]

DON'T BUILD THAT, YOU'RE BUILDING A DAMN WHISTLE.. LOL THATS ONLY 3.4 SQUARE INCHES OF PORT PER CUBEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

How many subs do you have? and what size?

That is just a rule of thumb and does not always apply, I actually HATE that little "rule" because the port MUST be designed to suit the woofer, not the enclosure it is in.

[imhungnurnot 9]

DON'T BUILD THAT, YOU'RE BUILDING A DAMN WHISTLE.. LOL THATS ONLY 3.4 SQUARE INCHES OF PORT PER CUBEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

How many subs do you have? and what size?

That is just a rule of thumb and does not always apply, I actually HATE that little "rule" because the port MUST be designed to suit the woofer, not the enclosure it is in.

He's using 7.6 cuft.. he's gonna have a lot of cone area.. he isn't building this for a 6 inch woofer.. more like an 18.. and for high excursion woofers that rule of thumb is necessary. At the very least he'll need to flare the port on both ends

Port Area Calc.

Edited June 16, 2010 by Im Hung N ur Not

[Duran 387]

DON'T BUILD THAT, YOU'RE BUILDING A DAMN WHISTLE.. LOL THATS ONLY 3.4 SQUARE INCHES OF PORT PER CUBEEE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

How many subs do you have? and what size?

That is just a rule of thumb and does not always apply, I actually HATE that little "rule" because the port MUST be designed to suit the woofer, not the enclosure it is in.

He's using 7.6 cuft.. he's gonna have a lot of cone area.. he isn't building this for a 6 inch woofer.. more like an 18.. and for high excursion woofers that rule of thumb is necessary. At the very least he'll need to flare the port on both ends

Port Area Calc.

With an 18" high excursion woofer the "rule of thumb" is not enough. That's the point, it's a bad recommendation in most cases because it's normally not sufficient port area for the given woofer. That was the point of my post, not to argue but to clarify.

[ssh 924]

thanks everyone for your input. Didn't steer me away from building but Argent's gonna make a long ass drive from CA to AZ, so I'm just gonna have him build it haha

thanks bromo for the write up, always nice to understand something you didn't know before.