National Style 4 Triple Resonator John Dopyera had an idea to put three metal cones into the body of a guitar to serve as amplifiers for te guitar's sound, and the resonator was born... Resonator guitars evolved when guitar makers tried to increase the volume of the conventional six-string guitar. Dopyera was the first to succeed, and he made the cones for his resonator guitars from aluminum, while the body of this guitar was made from silver, an alloy of nickel, copper and zinc. The Tri-plate's body did not resonate, unlike wooden guitars.The vibrations from the string were channeled to the resonators, instead of the top of the guitar. As the resonators took the place of the sound hole, the Tri-Plate also featured 3 rows of diamond-shaped sound openings on either side of the fingerboard.