Originally Posted by Taproot
I have seen people mention ports. Maybe port every other one? All of them? Suggestions on port size/type?
Do you want to tune them to a specific frequency with a port? I am on the wrong computer to pull up my archive, but I have a reference for a calculator for a ported panel-faced enclosure that's sort of like this: Port Length Calculator
In practice, it is typical to buy a longer port tube than you need, then during testing, cut its length sequentially until you get the required tuning. OTOH, if you want this to function as a pressure-based absorber, I'm pretty sure it needs to be air tight. If you want this to function like a Helmholtz absorber, search GS for Boggy's ported HH design. I just don't have time right now.