I use a pair of these ear muffs almost daily; they pretty much block out all sound well for me. Here are a few reviews for the product that address your concern

I use a pair of these ear muffs almost daily; they pretty much block out all sound well for me. Here are a few reviews for the product that address your concern: "you cannot hear what anyone is saying unless they shout, and even then, it is difficult to understand them." http://www.amazon.com/review/R20X9DNAJC9ZX3/ http://www.amazon.com/review/R20X9DNAJC9ZX3/ "I use to study while my 2 year old screams her head off (as long as someone else is watching her of course!)." http://www.amazon.com/review/R29TUUYEQY98W9/ http://www.amazon.com/review/R29TUUYEQY98W9/ "I use them while doing research in a library. It's unbroken silence despite screaming kids and adults talking into their cellphones. People no longer understand proper behavior in a library, but I don't care. I can't hear them. It's wonderful." http://www.amazon.com/review/RQBNEZ9CX3O19/ http://www.amazon.com/review/RQBNEZ9CX3O19/