Boy, does the English language never stop changing? Years ago no one ever referred to a regular old ball shaped foam pop filter as a wind screen. They certainly wouldn't keep out a 30 mph wind blast. That wool wind screen I posted a pick of will though and it'll block out highs a little too but not so much as you might think. But I've never been able to tell the difference between a foam ball and a filter made of mesh/nylon. Both are completely transparent to my ears. By the way, google, "foam pop filter" and you'll get 1,200 hits. Apparently I'm not the only one who remembers that foam filters used to always be referred to as "pop" filters. I would never refer to one as a wind screen because they simply will not keep out wind. As far as I'm concerned foam and nylon are still both pop filters. You can debate all day as to which is better at keeping out pops. But I've never been able to hear any loss of sound quality with either of them.
Also, I may be wrong but, as I recall, both foam and nylon filters block out lows--not highs. Any of you guys know John Beale? He's pretty well known in the video world. Anyhow he has a web page showing some spectral graphs of measurments he did of a speaker playing a 1khz test tone with his Sony VX2000 Camcorder 12" in front of it using the built in stereo mics while he had a fan off to one side of the mic blowing toward it at both 6.5 and 7.5 mph speeds. Obviously the higher the speed, the higher the fan noise in frequency. He measured the frequency changes between using no pop filter against using a foam one and then a foam one with a sock over it. He the took the Camcorder's sound file into Cool Edit afterwards and graphed out the difference in sound between them all. It shows the foam pop filter and with the sock cutting lows by 6 to 7db depending on whether the sock was on over the filter or not. The fan at 6.5 mph had a pretty high center curve at 42hrtz or so while the 7.5 mph fan speed centered the frequencies at around 60hrtz. The pops generated by speach would be even lower I would think. But anyhow, if you look at the graphs you'll see that the foam filter by itself didn't effect the 1khrtz tone or anything above at all. It just brought down the lows where it was supposed to. You can see the web page here:
Wind Test Obviously there wasn't much high end to lose in his test but still, do you really think you can hear a loss of anything with a foam filter? It doesn't sound any different to me really. An actual wool wind screen--yes--you can hear a loss of highs, but I can't imagine anyone hearing any difference between a mic with a foam pop filter and one without except for the loss of pops. And pop filter or no pop filter, I still have to talk/sing off axis a little if I'm close to the mic.