Apparently, from what I heard, it's illegal in the US to sell headsets that block sound in the 1k Hz to 2k Hz frequency range. The problem is that human speech is in that range and I want to block human speech so I can study. Normally, the product description reads something like this: Noise-cancelling headphones don't work for human speech and while I can drown out them with white noise, I feel like I'm going to go deaf from white noise. Does anyone know of any products designed to reduce human voices? I am OK with purchasing it from the black market or sketchy stores if necessary.