Ok, 2nd reply...
I went out and tuned in a rap station, and cranked the bass to max. FAR more bass than I'd ever want in real life. I didn't even have it particularly loud - and tried the "thumb test" over the ports. I could REALLY feel air moving in and out of them, and when I covered them, there was a rattle/resonation that wasn't there when I uncovered the ports. But as for a subjective difference in sound, I couldn't detect any whatsoever - but again, "not my music" and I'm not a real audiophile. But for 98 cents each, the pair of tubes are obviously doing *something* - the air pumping in and out was pretty significant. Which was what I'd expect.