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As a truly American instrument, resonator guitars can be heard in just about any style of music including Country, Rock, Blues and even Jazz. In addition, these unique guitars can be heard in many television programs, commercials and feature films.
With a body constructed of either wood or metal, usually brass or steel, the resonator is what sets these guitars apart from the crowd. The resonator is an aluminum cone that looks a lot like a stereo speaker cone and is housed in the large body cavity. These types of guitars are played either Spanish style (normal guitar playing position) or lap style with the guitar lying across the players lap facing upwards.
Typically they would be played with a metal or glass slide on one finger or with a metal bar (called a "steel") in the case of the lap style guitar. The resonator guitar is capable of lots of volume and the sound can range from thin and metallic to full bodied and rich and when combined with the slide can have an almost vocal quality.
Created about 1925 by John Dopyera, the first successful resonator guitar was the tricone metal bodied guitar. The tricone has three resonating cones placed in a triangle pattern and when played, has a rich, deep sound that is unique to the tricone. This guitar was manufactured by the National Corporation that was formed by John Dopyera and George Beauchamp.
The National Corporation also manufactured a guitar with a larger single cone that has the bridge sitting in a small wooden disc called a biscuit that rests upon the cone. It operates by transferring the vibrations of the guitar strings to the cone which are then amplified as the cone vibrates. As the tricone, the body was also constructed of metal.
In 1929, John Dopyera resigned from the National Corporation and went on to form his own business the Dobro Corporation. Interestingly enough, the name Dobro comes from the words DOperya BROthers. He was forced to develop a new style of resonator because his patents still belonged to the National Corporation. Because of this, John developed a new style of bridge that instead of resting on the center of the cone, it sat in the center of an eight legged "spider" that rested on the outer edge of the cone. Thus the vibrations from the strings are sent down through the cast aluminum legs and to the cone via the outer edges which gives the guitar a loud, full bodied tone that when combined with the wood body has become a favorite with Bluegrass musicians.
By 1932, the National Corporation was having financial difficulties and Johns brother Louis Dopyera purchased National and the two companies merged under the name National Dobro Corporation. During this time the company continued to grow and in 1936 they moved from California to Chicago, Illinois. Because they were growing at such a fast rate, They contracted other guitar manufactures such as Kay, Regal and Harmony to manufacture the wood bodies.
