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Port Length vs. Physical Port Length

1K views 28 replies 5 participants last post by  nicholask1993 
#1 ·
I'm lost on how long the wall in red needs to be to give me 36" of port length...

Torres says I need 33.75" of physical port length what exactly does that mean. I'm confused as to how the bend will effect the length of the port...

Help?!?
 
#14 ·
ur long port piece will b 24inches deep, n then the red piece should b 12inch deep then screwed into the first piece, just look at how ur screwing piece 2 into piece 1 to make sure u keep that 1.5" gap throughout the port, i will play with ur dimensions to make sure im right, im just going based on quick thinking :thumbsup::rofl:
 
#3 · (Edited)
can you put the port on the side going vertical? like 11x 4 and 27 inch long? 1.5" X 25.5 seems offly narrow. also 28hz tuning is way to low. im tuned at 33hz and kille 27 hz all day. you might run into some noise issues. esp since its so long. maybe someone with more knowledge can chime in
 
#4 ·
It gives me almost 13" of port area per foot which is enough according the the general rule of 12-16" per foot. Albeit on the lower end but it's for a single 15" running on 500w and maybe in the future 800w...
 
#7 ·
yeah your port area is OK but your port ratio is 17:1 ive heard that 8:1 is pushing it before you run into issues. 11x4 port is 2.75:1 ratio and its more port area
 
#10 ·
The physical port length is just the length of wood, since ur port bends, its just measured along the port in stead of manually measuring inside the middle of the port following in the bend, if u dont get it then i can draw a pic, im just dropping a duece right now
 
#13 ·
also do not make it the 1.5"x27 or whatever, you will have issues
the dimentions should not be more than 1:9
so its its 1" wide at most make it 9" tall, but that is still on the close side

if you want it on the bottom make it like 4" tall and 16" wide, will be some extra work but it will work properly
 
#16 ·
nope, just bend the port again lol, its only a small bend, i could b wrong about the physical port length, but when u measure ur port length i think u just measure from the middle of the port all the way, try it ur way first, u could always just make the port a hair smaller, that way ur tuning goes lower, plus u can shorten the length by a couple inches, will b a win win
 
#18 ·
Yup, cut ur port down in ur box calc by .75" n run a piece straight through the middle, for bracing the port, being that wide u will have nasty port flex
 
#21 ·
i just learned about the 9:1 ratio of width to hight ratio on the port (or vise versa)

but i made a port 2.5" x 38" and i had terrible loading issues, wasnt very loud, basicly didnt act as a port at all. i redid the port within the 9:1 rule and presto made it alot louder, sounded better and didnt have the loading issue
 
#23 ·
What if I have a port like this?

Say I wanted my port to be 12x3.5x24

All I would have to do it make each opening 12x2.75 and each port have a length of 12" and that would be the same, right?

Picture isn't to scale just to show what I'm talking about...
 

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#29 ·
Ok I finally get it lol



So the blue line equaling 18" would give me 36" of port total since there is 2 ports right?

If so I have finally designed a box and know how to measure port length correctly
 
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