Thanks erik,
It's been a very long time since I have been the details of speaker design. I burned out on the technical side of this hobby years ago and don't follow it near as much (that's one reason it's taking me forever to get around to setting up my subwoofers. To do it right is such a hassle I never get around to it. I just sit down and listen to my system as it is...)
I'd always noticed, though, that plugging the ports of a speaker seemed not only to tighten up the lower response, but also seemed to reduce the sense of dynamics, making it a bit more lifeless. So that seemed to at least subjectively ratify that myth. Perhaps that was just due to the loss of lower bass...(though I have both the larger and the slightly smaller version of the Thiel 3.7 and 2.7 speakers, the only difference being a 2" smaller woofer on the smaller speaker and not as deep bass, but it certainly sounds as dynamic or more than the bigger speaker with the lower bass....)