Last nite I redownloaded WinISD and entered Fi IB18 data via the recommended proceedure from a thread on this forum. It worked perfect, one of few times I entered driver data with almost no unknows before clicking save and it was accepted.
But, I plotted the recommended/suggested sealed and vented and then my vented to compare all 3. The suggested vented has a completly flat FR to 0. I wish.
under box, it has 0 for tuning freq, and vent it has 0 for length
group delay is flat 0 as well, so on and so on