|08:34 pm - Resonators (A Primer)|
I've become fascinated by, if not enamored of, resonophonic guitars. Most folks, if they’re somewhat knowledgeable on the subject, will look at a resonophonic guitar and say: “That’s a Dobro”. And they might be right; but not necessarily. “Dobro” is a brand name of a specific type of resonophonic guitars, but not all rezos are Dobros. Far from it – but more on that later…
Left: Wooden square-neck spider cone (Dobro-style)
Center: Brass-bodied round neck tricone
Right: Nickel-plated brass round-neck biscuit cone
“Resonophonic” guitars use spun metal cones that look like audio speakers to transmit the instrument’s sound, instead of using the guitar’s wooden top (soundboard) to project the strings’ acoustic vibrations. They were designed to amplify the sound of the guitar in the days before electric amplification existed.
There are three basic systems used to accomplish this: tricone, biscuit cone, and spider cone resonators. The names pretty much tell their stories: the tricone uses three separate cones actuated by a T-shaped bridge; a biscuit cone has the bridge attached to the center of the resonator through what looks like a hockey puck (biscuit) and with the spider cone the bridge is attached to the rim of the cone with an eight-legged frame.
Additionally, there are two basic styles of resonator guitars: round necked (like any other guitar) or square necked. Resonophonic guitars generally require heavier-gauge strings to overcome the threshold inertia of the cone’s mass. The heavier the string, the more “push” it provides to propel the cone. Since volume was the name of the game, the heavier the string, the better. But normal guitar necks couldn’t handle the extra tension exerted by the thicker strings, so many resonators were made with bulky square necks to handle the added strain. Additionally, bigger strings need to be set higher off the fingerboard to keep them from buzzing off the frets. These factors, in turn, required the square-necked guitars be played face-up, and led to the evolution of the lap steel and slide guitar (but that’s another story…). The advantage is that they can accept a wide range of tunings. Round-neck resonators can be played face-up (lap style) or face-out, like a normal guitar, but are much more limited in how they can be tuned.
And finally, there’s the matter of… matter. In acoustic guitars, the tone of the instrument is determined by the characteristics of the woods used for the components and how they’re connected to each other. Since the tone of a resonophonic guitar is primarily determined by its resonator cone (or cones), the material of the rest of the instrument is more of an augmenting than determining factor. Cheaper laminates (plywood) actually sounded better than more-expensive solid tonewoods. Metal bodies made the metal cones ring and sing like a bell, so they began making rezo bodies out of bell materials: steel, brass, and nickel.
The history of how these different styles evolved, and the incestuous relationships between the early manufacturers, is a fascinating story in and of itself, but others have told it well so I won’t dwell on those topics here. Suffice it to say certain manufacturers became associated with specific types of resonators. The Dobro company specialized in square-neck, spider-cone wooden instruments that are played face-up, usually on the lap. This seems to be the preferred type for Bluegrass and Country music. (These instruments even seem to have an Appalachian drawl in their tone...) These typically use REALLY heavy strings, so the strings are set far above the fretboard; too far for fingering, so they’re almost always played with a slide bar, or steel.
Not to be confused with the National Steel, or just National. This was the original resonophonic brand, which made tricone resonators. This type is considered to have the richest and fullest tonal profile, but were expensive to build and therefore buy. One of the founding partners came up with the single-cone biscuit bridge design to make a more affordable version, but the other partners wouldn’t go for it. So the biscuit-bridge designer set off on his own and founded the Dobro company to make the single-cone rezos. But before he could, the other partners tried to nip the impending competition in the bud by patenting his biscuit-bridge design under National corporate ownership. To get around this, he turned the cone over inside the guitar body and came up with the spider frame to attach it to the bridge.
The relatively inexpensive Dobro resonators were so popular that National had a hard time selling their tricones, and almost went out of business. So they dusted off their biscuit patent to compete. To distance themselves from Dobro, National focused on making steel guitars. It wasn’t long before National was known more for their steel single-cone biscuit resonators than their original tricone. Although the tricones may have sounded better, the single-cones were louder, and in addition to cheap, loud was what it was all about. Although they continued to manufacture some tricones, National licensed the design to numerous other instrument companies to manufacture under their own brand. Just as Dobro became the generic name for spider-cone, wooden square-necked resonators, National became synonymous with biscuit-cone, steel-bodied round-necked guitars. As country and bluegrass bands took to the Dobro, bluesmen, buskers and itinerant musicians took to the National.
Current Mood: Groovin'
Current Music: Roy Rogers and the Delta Rhythm Kings: