on the mac, the spring attached muffler had a gasket, they don't do much after a few years of service, mine was gone completely, once it's to that point it's easy to get out of it's cradle or whatever you want to call it, with the stock unmodified muffler they're a little louder than say a weedeater brand, but not much noise comes out of the 1/4" hole in the thing...

with the two 1/2" tubes coming out of my muffler, it's pretty loud in front of my garage, but pretty quiet at the field...