Will wearing dual protection — an earmuff in addition to earplugs — provide added protection against extreme noise levels? What are the pros and cons of using dual protection? Find out the answers by downloading “Sound Source #11a,” a bulletin released by the Bacou-Dalloz Hearing Safety Group in Smithfield, RI. Also called the “Dual Protection” bulletin, it’s authored by audiologist Brad Witt and is available at www.hearingportal.com/hearingconservation/hc-snd-ame.asp.