National's produced two types of resonators: The single cone and the tricone. Those instruments use very thin aluminium speaker cones, to mechanically amplify the sound of the instrument. This style of mechanical amplification was invented in the 1920's, before the advent of electric instruments.
In this single resonator model the convex 9.5" diameter cone has a maple "biscuit" on top of the cone. The biscuit has a wooden maple saddle which the strings pass over, like a conventional acoustic flat top guitar. But unlike flattop acoustic guitars where the vibration of the wooden body creates the sound, in a National resonator instrument the body acts as a speaker cabinet. When the strings are played, the vibration goes through the saddle to the bridge and then vibrates the speaker cone causing it to "resonate" and amplify the sound. Because there is fairly direct transmission of vibration from the strings to the resonator, the single resonator guitar is the loudest of the resonator guitars.
The National Style O Resonator guitars where produced between 1930 to 1941. They had either Square neck (D) or Round neck (C). The guitar featured a single cone resonator, nickel plated body with sand blasted Hawaiian scene on back and palm trees on front and solid area on sides, round shoulder, upper F-holes, round neck, dot inlay fingerboard, bound ebony fingerboard. There were 6 different variations in the sand blasted Hawaiian scene, and 8 total Style O variations if you include body changes.
This guitar is a Style O with a C neck owned by guitarist Arlen Roth. This single resonator guitar is a brass bodied instrument nickel plated and etched with the distinctive Hawaiian palm tree design. The maple neck has an ivory bound ebony fretboard which has been restored to its old glory.
Here is what Arlen says about this guitar:
"My 1930's National Resonator guitar. I have played this on every album of mine, going all the way back to my first album in 1976. John Hammond, Jr. found this for me, and I found it in the famous Silver and Horland Music shop in NYC, not knowing I would soon LIVE in the same building the next year!”
The guitar was often played using a dime. It was the habit to but such coins through the f-holes of the resonator guitars, so that they get some nice extra resonance. This guitar has several dimes in its body and therefore has a special resonance.