WinISD Port length calculation for 1 or multiple vents

[Marzo]

Hi all,


I have been snooping around the forum for quite a while now but this is my first post. I am new to building but have been researching quite a lot and getting a lot of info from this forum, so thank you all! I am now at the stage that I am designing my first speaker from scratch.

I have searched the better part of the past two hours on this forum and others, but haven't been able to find an answer to my question.

Build details:
I am designing a vented speaker with a round port and have been playing around with WinISD. I am using two parallel Dayton Audio TCP115-8 4" drivers that I got from a friend who is upgrading his kit. I am still messing around with the box sizes but am trying to keep it as small as possible. Ports are at the rear mounted.

What I want to know:
in WinISD, I am playing around with 1, 2 or 3 vents. If I am looking at 1 vent, it gives me a length X. When I look at 2 (or 3, 4, etc.) vents, it gives me a length Y. What I want to know is, is this the total length for the combined vents (i.e., for 2 vents, do I divide the length it gives me by 2), or is this the length for each individual vent?


Thanks a lot!

Regards,

Marzo

 

[ernperkins]

That's for each port, no dividing necessary.

 

[Marzo]

Thanks so much! Really a duh question but better safe than sorry 🙂

 

[TMM]

When you have multiple ports it's the same as having single port of the same total area, hence why they have to be longer, just the same as when you increase diameter of a single port.