Port Construction Question

[4DMAN00 10+ year member]

I figured out that with a 1.5 cu ft box tuned at 32hz and port area of 24 sq in, I will need a 37" length port for my box which will not fit a single bend in the port. Will having a multiple bends cause any problems with port. (I think the way ED box suppestions are.)

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[RMKrider1 10+ year member]

Multiple bends will be fine. Is that 1.5 after sub and port displacement? That port will take up about half a cube of airspace!

 

[Trixter 10+ year member]

Multiple bends are ok to use if you carefully measure them out and keep them square. You can either do it back and forth like a the first pic. Or you can run it along the back side and possibly even come up the opposite side. The second and third one are the ones I like because it gives you less chance for error in measuring and keeping you 90's tight. Just to give you some ideas....

 

[swimfreak26 10+ year member]

As trixter said, they'll be fine as long as you keep them square.

In other words, make sure that every section of the port has the same cross sectional area and you will be great. Make sure, too, however that you are accounting for port displacement in your calculations or it will not come out tuned right.

 

[4DMAN00 10+ year member]

Thanks for the replies guys, i have one more question:

Can you have the port mount on the outside and then enter into the enclosure (see attachment = Blue outline on outside). or does the port have to be a part of the net air space.

 

[pj_chevy03 10+ year member]

TRixter u figured for me how long me port should be and it was 3.76 in> right?? the guy in this thread has even a smaller box but why is his 37 in. long/???? am i missin somehting

 

[4DMAN00 10+ year member]

I've remember your thread but i just can't remember what your sq in of your port. On this one the port is 24 sq in (8x3) tuned to 32 Hz. That might be the deal or i could of screwed on the JL audio equation (this is close to what WINISD shows).

 

[4DMAN00 10+ year member]

Ok on PJ's other thread brings up a question for me, will the 24 sq in port area be better than say a 16 sq in or smaller port area. because if i can get away with a small port area my box can be smaller.

 

[4DMAN00 10+ year member]

should i use the min port area according to the sub using. because i been to one site that gave me a min port area for RE SE 10 is like 23.??? sq in. And it sounds like a trail and error to build boxes. i know a spl competitor rebuilds his box like changing a pair of shoes. if it don't work right or not loud enough try again.

 

[Trixter 10+ year member]

TRixter u figured for me how long me port should be and it was 3.76 in> right?? the guy in this thread has even a smaller box but why is his 37 in. long/???? am i missin somehting

Because the smaller the box the longer the port needs to be to maintain the tuning freq. When you make a sealed box, the larger the lower the freq., the smaller the higher the freq. In a ported box, generally, a longer port will make it lower freq. and shorter port will make a higher freq. So a way to make a small box have a low freq. is to have a long port.

 

[Trixter 10+ year member]

should i use the min port area according to the sub using. because i been to one site that gave me a min port area for RE SE 10 is like 23.??? sq in. And it sounds like a trail and error to build boxes. i know a spl competitor rebuilds his box like changing a pair of shoes. if it don't work right or not loud enough try again.

It would be safe to go with the min. that is recommended. You shouldn't have to build multiple boxes to get it right....unless you plan on competing with it. Remember that is the min. recommended. You can go more if it is easier depending on how your box is set up. (ie: box is 12" tall so make a port that is 2.5" x 12" and get you 30sq".)