Originally Posted by
walpurgis
Right.
Done a bit of research and working out. The cabinet volume is just under 18 litre. Taking the bass driver resonance as 60 Hz, it may be wise to tune the port slightly below that to avoid the box resonance overlapping that too much and creating larger than desirable 'hump' (there wiil be a slight one), so I'd aim for 50Hz, that will also allow the bass to extend down a bit further, there will certainly be sufficient output from the driver at that frequency to excite the reflex action. This will require a tubular bass port of 6 inches length and 2 inches inside diameter. There will be roll off below 50 Hz, but you should still get some output at 40Hz, maybe even lower if you're lucky.
I use usually use cheap plastic waste piping from places like B&Q for ports, but as Grant says, there are custom ports available that can be adjusted for length, allowing cabinet tuning to be played with.