I've read that windscreens do affect the sound quality...not much mind you but....where did I read that?
Yeah, manufacturers do sometimes spec the attenuation. Here's one from Neumann:
"Wind Screens
Windscreen WNS 100
Close range sounds, wind, and fast movements of the microphone boom, all may cause interfering noises. To avoid these unwanted sounds, windscreen accessories are available.
Typically, they are made out of open-cell polyurethane foam. These windscreens do not cause interfering resonances and do not influence the directional pattern. Only in the upper frequency range is the output level slightly attenuated. The wind noise attenuation was measured without electrical filtering in a turbulent air stream traveling at 20 km/h, generated by a noiseless wind machine.
Windscreen for KM 100 and Series 180. Diameter is approx. 45 mm. Suppression of the wind noise approx. 18 dB. Attenuation at 15 kHz approx. 2 dB. Supplied with initial purchase of the microphone." Personally I can hear a difference between using them and not using them, but just barely.
Drew