This I have tried*s*. And they are actually only good at HIGH voices (like 38 db). And most of them are made like "you can talk when you work with a friend, and you will not hear the high noises". They don't protect the low-noise range..
But it would be a good idea if they made some..
The last ones I checked was some, which others used on shooting contests! When you have to really concentrated shooting, all other noises like from the public etc. should be kept out, so you really can concentrate 100% on shooting. buuut they are not protecting 100% of all noises either. Like low dog sounds behind walls. low "deep" noises like footsteps upstairs. But these was the best I found, to use with earphones 
.
This could actually be a good tip to a firm*gg*. To make headphones, specially made for selvimprovement tools. "Totally peach phones"*g*..
By the way.. I'm quite ok with what I have achieved by using NLP here on this subject. Because it will make you psycologically stronger. Learning to relax totally in a noise enviroment. If you can conquer that, you're gooood!*s*
