Unique 49+ Martin Light Guage Acoustic Guitar Strings. With martin retro strings, you get a guitar string set that sounds like nothing else on the market. According to an old interview from the well, what else would you expect from a virtuoso like joe satriani, whose music is filled with fast legato passages, than to use light gauge strings? They feature a tension of 168.5. In general, lighter gauge strings put less pressure on a top and will produce a lighter softer.