I wouldn't know, the amp was blown when I got it.
the port exits the enclosure through the bottom front, below the forward facing driver. It is a large oval at the exit, reducing port diameter as it extends diagonally up into the enclosure.
I watched another movie last night at moderate volume levels and it makes the sound pretty consistently across lower frequencies. It really seems to be a fluttering sound the air is making as it squeezes through the narrower port opening inside the box.