A number of companies make "tuned" ear plugs to allow some sound through with a desired frequency curve, but reduce SPL to safe levels. I've used Etymotic, which sound great but I personally like a little more reduction. Alpine which I thought had enough reduction but too much coloring, and I settled on Earpeace, for like $25 on-line. Silicone, re-usable and easy to clean and they come with three filters to swap in or out depending on your needs / tastes.