In an effort to work with a smaller ported box, could you save on space/displacement by using a round port instead of a typical slot port? And it seems that the smaller your port's diamater the shorter it needs to be to stay at a certin frequency, when does it become too small? Can someone explain porting to me a little bit? I've looked around and have yet to really understand it.
Yes, you can use round or flared ports to save volume in the enclosure. Also, flared ports will reduce turbulence and you can use less port area.
For example, Say you have a 1.5cuft net box and you want to used around a 20sq inch slot vent. That will take up quite a bit of space in the box. But in most cases, depending on power, a single 4" port will do the trick and not have port noise. It will both be shorter and have a smaller cross-section area. Meaning you save on port displacement.