Hi Pete I ran a quick simulation on WinISD for you for the 206E and it looks like it really doesn't want to fit a 45liter cabinet smoothly without quite a lot of series resistance to raise the qts. from .18 to .40. I have tried this trick in the past and it works but I think that it robs some of the detail from the mids and highs but it should produce good bass. My results are a port tuning of 40Hz with a 3"ID tube 5.15" long.This will give a port velocity of Mach 0.15 . This alignment will require at least a 6 Ohm audio grade resistor in series with the driver. You should be happy with this combination unless you are expecting to use a low powered amplifier at which case your efficiency will suffer terribly especially if you intend to install a baffle-step correction circuit. Good luck with your project Ron Brady