I bought these for use in my Jeep. They do a terrific (and very noticeable) job eliminating wind noise from my soft top (and my usually open windows).They also have terrific sound compared to regular headphones in this price range. I hate hiss, but the tiny amount they add is unnoticeable when the are being used for their intended purpose. (In a quiet environment, I go back to my Philips Surround Sound earbuds.)If you look at the specs for noise cancelling headphones, you'll see that the active cancellation handles low frequencies (50-1500Hz). Higher frequencies are eliminated primarily by the earphone/headset physical design itself.