However, as to the actual point, I had done some experiments with reticulated foam in the ports of subwoofers to see if it could reduce port noise. I looked at two things, a reduction in port resonances, a reduction in port chuffing. I got the idea from Earl Geddes and he directed me on how to conduct the tests. I did all the tests with a low noise calibrated measurement microphone and nearfield measurement of the port itself. Ultimately, I didn't find it worked very well for either. Port resonances were only marginally reduced, not enough to matter in many cases. Good port design in the first place turned out to be more important. It also didn't help port chuffing. In fact, best I could tell from this crude method of measuring chuffing, it made it worse.
What I've continuously found is that the port is hardly ever the real culprit; it's simply that the internal resonances of the enclosure are leaking out of the port. I've tested this numerous times (sometimes sharing the data, sometimes not) by stuffing the port and re-measuring the speaker to see if a mid-to-upper-midrange resonance remains in place and the majority of the time it does. As reviewers/viewers of the data, we typically jump to "port noise" because of the high amount of energy escaping through the port but it's almost always enclosure resonance(s) that are the real culprit.