Port length question with WinISD

[GregU 10+ year member]

I'm designing a box with WinISD and I've never had to build a box with more than one port, brings me to a question.

I have to have 2 ports to keep the mach down, port dimensions are 2" x 5" ID. WinISD says that the port length would need to be 39" long. Now, does that mean that each port would need to be 39" long or 19.5" long for each port to total 39"?

This is for an IDMAX 10" = 1.75ft3 @ 27Hz

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[RAM_Designs 5,000+ posts]

for each

 

[GregU 10+ year member]

for each

That's fu*ked up:verymad:

So whats the advantage of multiple ports?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[RAM_Designs 5,000+ posts]

That's fu*ked up:verymad:
So whats the advantage of multiple ports?//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

None, it's better/easier to do a single larger port that doesn't have to be quite as long as two smaller ports.

 

[GregU 10+ year member]

None, it's better/easier to do a single larger port that doesn't have to be quite as long as two smaller ports.

Well, shiet.......

Kinda hard building a box so small with such a low tune.

On ID's website they say on a 1.68ft3 @ 25Hz to make a port 3" I.D. x 17.75" long....... which is WAAAAAYYYYYY off from what WinISD says.//content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

Well, not way off but the mach is like .24 which would whistle pretty **** bad