As a beginner guitar player, one of the most difficult hurdles to overcome is that of transition between chords. We learn the chords to our favourite songs or a new complex chord shape, but when it comes to making music with them, our lack of muscle memory and dexterity inhibits us from stringing these chords together in a meaningful and comprehensive manner.
Only two or three frets are needed for the guitar chords—major, minor, and dominant sevenths—which are emphasized in introductions to guitar-playing and to the fundamentals of music. Each major and minor chord can be played on exactly two successive frets on exactly three successive strings, and therefore each needs only two fingers. Other chords—seconds, fourths, sevenths, and ninths—are played on only three successive frets.
All three principal types of resonator guitars were invented by the Slovak-American John Dopyera (1893–1988) for the National and Dobro (Dopyera Brothers) companies. Similar to the flat top guitar in appearance, but with a body that may be made of brass, nickel-silver, or steel as well as wood, the sound of the resonator guitar is produced by one or more aluminum resonator cones mounted in the middle of the top. The physical principle of the guitar is therefore similar to the loudspeaker.