I'm making a triple chambered box and each chamber is 2.2cf tuned to 31hz. Port dimensions are 1.57"x11.16" and when I use this calculator if I select yes or no on the slotted port option I get different results.
This box will be using a slotted port, but other calculators I have which don't have the option to choose a slotted port all say closer to 18.8" (like winISD).
Using your calculation methods or reasoning could anyone tell me what port length I'd need to get the tuning frequency I'd like.
edit: this website also gives me the two same options, 13 or 18