Port length, 1.5 Cubes, 32Hz

[Rc 415 10+ year member]

Ok, so I have the box built, its 1.5 cubic feet, and I need to tune it to 32 Hz, so I plugged the numbers into the calculator below, and I get right around 36". Is this 36" the length of each port or is it like the statement below? (I have three 3" Aeros)

http://www.psp-inc.com/psp-inc.com/public_html/..%5Ccgi-bin%5Cport_length_calculator.cgi

Its def. like i said before,this is the combined length for all 3 tubes.I went through every formula i have bookmarked,and they all come out the same.

3 3in ports@roughly 12in long will give you 32hz tuning.

Can anyone verify this statement? I always thought diffrent.

Click to read more...

 

[bjfish11 5,000+ posts]

Length Per Port

 

[bimma85 5,000+ posts]

if you enter 2 4" ports and it says 20" long....that means 20" long for each port...not 10" long each port.

 

[Rc 415 10+ year member]

So each port needs to be 36 inches then?

 

[bimma85 5,000+ posts]

So each port needs to be 36 inches then?

if that is what it said....yup

 

[bjfish11 5,000+ posts]

So each port needs to be 36 inches then?

Yes

 

[Rc 415 10+ year member]

Ok, thanks guys.

 

[Rc 415 10+ year member]

My last question is, will I notice a big diffrence between having flared ports and non flared ports?

 

[xluben 10+ year member]

you also have to take port displacement into consideration, since your box is already built.

so with 3, 3" dia, 36" long ports that's about 0.4 ft^3 of displacement, which put the box at 1.1 ft^3 and the tuning at 37Hz!

 

[ruger 10+ year member]

i been wondering that also, is this right ?

3cu. box with 4, 4" flared tubes 13 in long would be 55hz

if i plugged up one port, the closest i get would be

1 port pluged around 47hz

2 ports pluged around 39hz

3 ports pluged around 28hz

basiclly trying to make 1 box for a 10" that i dont have to remake.

for comp. and dd. so is that right?

 

[Rc 415 10+ year member]

you also have to take port displacement into consideration, since your box is already built.
so with 3, 3" dia, 36" long ports that's about 0.4 ft^3 of displacement, which put the box at 1.1 ft^3 and the tuning at 37Hz!

You dont have to worry man, I got that under control, the box currently is extremely close to 2 cubes.

 

[Rc 415 10+ year member]

My last question is, will I notice a big diffrence between having flared ports and non flared ports?

Now...back to my question.

 

[Decipha 10+ year member]

you won't hear as much port noise with a flared tip... thats about the only difference

 

[bimma85 5,000+ posts]

you also have to take port displacement into consideration, since your box is already built.
so with 3, 3" dia, 36" long ports that's about 0.4 ft^3 of displacement, which put the box at 1.1 ft^3 and the tuning at 37Hz!

you positive? I was thinking the same thing, but jntar said they already figure the port displacement in the calc. Said he wasnt 100% sure, though.

 

[Rc 415 10+ year member]

you won't hear as much port noise with a flared tip... thats about the only difference

How bad will the noise be in reality though?