The Shure SM81 is a classic cardioid condenser mic that shines bright on acoustic instruments. This small diaphragm staple, originally released in the 1970s, has found a home with countless studios and stages thanks to its detailed pickup, exceptionally low noise, and rugged build quality. Unhyped and true from one end of the frequency range to the other and nearly impossible to clip, the SM81 remains a tried-and-true mic that should be in every engineer's collection.