What is the difference between a Dobro and a National?

They’re two designs from the same family of luthiers. National (founded 1927) uses a biscuit bridge on a downward-pointing single cone, or a tricone, almost always in a metal body — bright, cutting, Delta-blues voice. Dobro (founded 1928 by John Dopyera and his brothers after he left National) uses a spider bridge on an upward-pointing single cone in a wood body — sweeter, bell-like, bluegrass voice. “Dobro” is now a Gibson trademark but is used generically for any wood-body spider-bridge square-neck resonator.

Should I get a round-neck or a square-neck?

Depends on the music. Round-neck plays like a regular guitar — fingerstyle, flatpick, or bottleneck slide on a finger; great for Delta blues, acoustic blues, and standard-tuned fingerstyle. Square-neck has a raised nut and is played flat on the lap with a steel bar in open G — the bluegrass dobro setup. You cannot easily switch a square-neck to round-neck or vice versa.

Are resonators acoustic or electric?

Acoustic. The cone is a passive mechanical amplifier — no electronics. Many modern resonators add an internal pickup or microphone for stage use, but the cone itself is purely acoustic.

What tuning is the standard for a Dobro?

Open G high: G–B–D–G–B–D (low to high). The whole instrument forms a G major chord at the open position, which is exactly what you want under a steel bar — the bar functions as a movable barre across all six strings.

Do I need a slide to play a resonator?

Not always. A round-neck resonator can be played with fingers alone (in standard tuning or open tunings), with a flatpick, or with a slide. A square-neck resonator needs a steel bar — you cannot fret it with your fingers because the nut is raised. Many resonator players use both round-neck fingerstyle and slide.

Why is a metal-body resonator so much louder than a wood one?

Two reasons. First, metal bodies don’t absorb cone vibration the way wood does — the cone’s energy is reflected outward more efficiently. Second, the National biscuit-cone design itself is more efficient than the Dobro spider-cone design — less mass on the cone’s apex, faster response. The combination is what gives a Style O National its legendary cutting power.

Resonator Guitar Gear — cones & bodies

The parts of a resonator

From the outside a resonator looks like a guitar with a polished round metal plate in the middle of the top. That plate is just a perforated cover. Underneath, the actual top has a large round cutout, and a thin spun-aluminium cone sits in that cutout. The bridge transfers string vibration directly onto the cone rather than into a wooden soundboard.

Cone: a thin, spun aluminium cone — the actual speaker of the instrument. Anywhere from 9.5″ (single-cone) to a set of three 6″ cones (tricone) in diameter. The cone replaces the wooden top as the radiating surface.
Coverplate: the perforated metal disc you see from the top, screwed over the cone for protection. Often punched with slots, F-holes, or a stylised wheat-sheaf pattern.
Bridge (biscuit or spider): the bridge sits directly on the cone — not on the wood. A biscuit bridge is a small maple disc on the apex of an inverted cone; a spider bridge is an eight-legged aluminium spider that sits on the rim of an upward-pointing cone.
Soundwell: a wooden or laminate ring inside the body that holds the cone, isolates it from the body wood, and routes air through screened soundholes.
Body: built from either wood (laminate or solid) or metal (brass, nickel-plated steel, or German silver). The body wood/metal affects projection, warmth, and harmonic complexity.
Soundholes: screened f-holes, round holes, or sometimes both. They are not the main sound radiator — the cone is — but they vent the body and shape the low end.
Tailpiece: a metal trapeze tailpiece anchors the strings at the bottom of the body, transferring tension into the body rather than into the bridge/top like an acoustic guitar.
Neck: either round (Spanish hold, fretted normally with the fingers or with a slide) or square (raised nut, played flat on the lap with a steel bar). Same body, very different instruments.

Cone & bridge designs

Three patented cone systems define every resonator guitar ever made. The Dopyera brothers and their cousin John designed all three between 1925 and 1928, and the choice of system is the single biggest tonal variable on the instrument.

Design	How it’s built	Sound & use
Tricone	Three small ~6″ aluminium cones in a triangular layout, joined by an aluminium T-bar bridge that sits across all three. Original National design (1927).	The most complex and sweet-sounding resonator — long sustain, rich harmonics, slightly less raw volume than a single cone. Favoured by Hawaiian players, by Sol Hoopii historically, and by modern slide stylists like Bob Brozman.
Single cone, biscuit bridge	One ~9.5″ cone pointing downward (apex up), with a small maple “biscuit” on the apex and a saddle on top of the biscuit. National-style.	Loud, percussive, raw — the classic Delta blues bottleneck voice. Strong midrange honk and immediate attack. Used by Son House, Bukka White, Tampa Red — and the heart of the National brass and steel-body sound.
Single cone, spider bridge	One ~9.5″ cone pointing upward (apex up), with an aluminium “spider” bridge whose eight legs sit on the rim and meet under a saddle at the centre. Dobro-style.	Sweeter, bell-like, with a singing sustain — the bluegrass Dobro voice. Designed by Rudy Dopyera at Dobro in 1928 specifically to compete with the National sound and avoid National’s biscuit-bridge patent.

Dobro vs National

“Dobro” and “National” are two brand names that became shorthand for two very different resonator designs. Both were founded by members of the Dopyera family within a few years of each other and the rivalry shaped the entire instrument category.

National (1927): founded by John Dopyera with George Beauchamp. Builds biscuit-bridge single-cone resonators and tricones, most famously in metal bodies (brass, nickel-plated steel, German silver). The sound: bright, loud, percussive — Delta blues, Hawaiian, urban acoustic blues.
Dobro (1928): founded by John, Rudy, and Ed Dopyera after John left National. The name is a contraction of Dopyera Brothers (and also means “good” in Slovak). Builds spider-bridge single-cone resonators in wood bodies. The sound: sweeter, bell-like — bluegrass dobro, Western swing, country.
Trademark today: Gibson currently owns the “Dobro” trademark. Players still use “dobro” generically for any wood-body spider-bridge square-neck resonator, but other builders call them “square-neck resonators” or use their own model names.
Modern builders: National Reso-Phonic, Gibson (Dobro), Beard, Scheerhorn, Republic, Recording King, and many smaller luthiers cover both design families — you don’t need to chase vintage instruments to get either sound.

Body materials

Resonators are built out of two very different families of material, and the body material affects tone almost as much as the cone does.

Body	Build	Sound
Brass	Soldered yellow-brass sheet, usually nickel-plated. Heavy — 8–10 lbs.	Warm, complex, with a long sustain and a sweet midrange. Often the “chocolate-y” National sound favoured by acoustic blues players.
Nickel-plated steel	Soldered steel sheet, nickel-plated. Slightly lighter than brass.	Brighter, sharper, more cutting — the classic National Style O sound. Bites through a band and projects outdoors.
German silver (nickel silver)	Soldered alloy of copper, nickel, and zinc. Used on the highest-tier tricones.	Smoothest and sweetest of the metal bodies — the legendary Style 4 tricone sound. Long sustain, lush harmonic content.
Wood	Maple or mahogany laminate or solid — the standard Dobro construction. Spruce or mahogany top with maple back and sides on premium builds.	Warmer, woodier, more guitar-like attack than metal. The bluegrass dobro voice — bell-like with the spider bridge, but with acoustic-guitar bottom end.

Square-neck vs round-neck

The same body, cone, and bridge can be built as two completely different instruments depending on the neck. The neck dictates whether you play the instrument like a guitar or like a lap steel.

Round-neck: a normal guitar neck. Held in the Spanish position against the body. Can be played with fingers, a flatpick, or a slide (bottleneck on the third or fourth finger). The standard for blues resonator playing — Son House, Bukka White, modern acoustic blues. Usually strung at standard guitar action and standard tuning (EADGBE) or open G/open D for slide.
Square-neck: a thick, squared-off neck with a raised nut that holds the strings 1/2″+ off the fingerboard. Cannot be fretted with the fingers. Played flat on the lap (or on a strap held flat across the body) with a steel bar in the left hand. The standard for bluegrass dobro — Josh Graves, Jerry Douglas, Mike Auldridge, Rob Ickes. Almost always in open G GBDGBD.
You can’t swap: a square-neck cannot be re-fretted into a round-neck (or vice versa) without rebuilding the instrument. Choose based on whether you want to play slide-blues guitar (round-neck) or bluegrass dobro lap-style (square-neck).
Hybrid “high-action” round-neck: some players set up a round-neck resonator with a tall slip-on nut extender and slightly higher action so they can play it both ways — standard-tuned in the Spanish position, or laid flat for lap-style. A practical compromise, not a true square-neck.

Tunings

Resonators live in a small set of tunings — almost all open tunings, almost all chosen so the open strings spell a chord that fits under a slide or steel bar.

Tuning	Strings (low → high)	When you’ll use it
Open G high (Dobro)	G–B–D–G–B–D	The bluegrass-dobro standard. Strings 1–2–3 are G–B–D, an octave above the bottom G–B–D. The whole instrument is a G major chord at the open position. Used on essentially every square-neck dobro recording.
Open G low (blues)	D–G–D–G–B–D	Slide-guitar open G, the Keith Richards / Mississippi blues tuning. Round-neck only. The low E string is dropped to D and the A string up to G — same chord shapes as standard open G slide guitar.
Open D	D–A–D–F#–A–D	Common blues slide tuning. The whole guitar is a D major chord at the open position. Used by Son House, Bukka White, and many Delta-blues bottleneck players.
Standard EADGBE	E–A–D–G–B–E	Round-neck resonator played like a regular guitar — fingerstyle or with a flatpick, no slide. National-style biscuit-cone resonators do this very well for percussive acoustic blues.
D-A-D-G-A-D (DADGAD)	D–A–D–G–A–D	Round-neck only. Modal Celtic and folk fingerpicking tuning used by some modern resonator players — the resonator’s metallic attack adds a distinctive voice to Celtic arrangements.

String Warrior uses the bluegrass-dobro open G high (G–B–D–G–B–D) as the default. See the resonator chord charts for diagrams in that tuning.

Strings

Resonators run heavier strings than acoustic guitars. The cone needs energy to move, and the high tension of dobro-style square-neck tunings demands medium or heavy gauges. Light guitar strings will sound thin and feel floppy.

Square-neck dobro (open G high): medium or heavy gauges, typically .016 / .018 / .026w / .035w / .045w / .056w. The tension keeps the cone driven and the bar stable.
Round-neck slide blues: mediums (.013–.056) are the most common starting point. Heavier than fingerstyle gauges, lighter than dobro sets.
Round-neck fingerstyle (standard EADGBE): standard acoustic mediums or lights work fine. The cone responds best to a firm attack — very light strings under-drive it.
Phosphor bronze vs nickel-plated steel: phosphor bronze is the acoustic-guitar default and works on wood-body resonators. Some metal-body Nationals respond better to nickel-plated steel, which is brighter and matches the metallic character of the body.
Ball-end: resonators almost always use standard ball-end strings — the trapeze tailpiece accepts them like any acoustic guitar.

Slides, bars & picks

The resonator’s voice is inseparable from slide technique. The choice of slide or bar — its material, its weight, and how you hold it — is as much a tonal decision as the cone itself.

Bottleneck slide (round-neck): glass or brass tube worn on the third or fourth finger. Glass is warmer, brass is louder and more cutting. Length should cover all six strings for full chord slides.
Stevens steel / bullet bar (square-neck): a solid steel bar held in the left hand, used like a movable nut. The Stevens-style bar has a rounded nose for picking up individual strings; the bullet bar is fully cylindrical.
Fingerpicks + thumbpick: the standard right-hand setup for dobro and acoustic resonator blues. Two metal fingerpicks and a plastic thumbpick give the volume and attack needed to drive the cone.
Bare fingers: works on round-neck resonators for warmer, less aggressive acoustic blues — but you lose volume against the cone’s sensitivity to a firm pick attack.
Capo: a regular acoustic guitar capo works on round-neck resonators. Square-neck players don’t use capos — the steel bar is itself a movable capo across all six strings.

A short history

In the mid-1920s, vaudeville guitarist George Beauchamp asked Slovak-American luthier John Dopyera for a guitar that could compete with horns in pre-amplifier dance bands. Dopyera’s answer was the tricone — three small aluminium cones inside a metal-bodied guitar — patented and built by the new National String Instrument Company in Los Angeles starting in 1927.

John Dopyera left National in a dispute and, with his brothers Rudy and Ed, founded Dobro in 1928. Dobro’s big innovation was the spider bridge: a single upward-pointing cone with an eight-legged aluminium spider as bridge — sweeter and cheaper to produce than the tricone, and clear of National’s biscuit-bridge patent. National responded with their own single-cone biscuit-bridge design (the Style O and Duolian), and the modern resonator landscape was set.

The instrument became the Delta blues sound through players like Son House, Bukka White, and Tampa Red. The wood-body Dobro became the bluegrass voice through Josh “Buck” Graves with Flatt & Scruggs in the 1950s, then Mike Auldridge, Jerry Douglas, and Rob Ickes from the 1970s onward. Both lines — metal-body slide blues and wood-body bluegrass dobro — remain alive today, and both share the same Dopyera-family DNA.

Once you know the gear, put it to use:

Frequently asked questions

What is the difference between a Dobro and a National?: They’re two designs from the same family of luthiers. National (founded 1927) uses a biscuit bridge on a downward-pointing single cone, or a tricone, almost always in a metal body — bright, cutting, Delta-blues voice. Dobro (founded 1928 by John Dopyera and his brothers after he left National) uses a spider bridge on an upward-pointing single cone in a wood body — sweeter, bell-like, bluegrass voice. “Dobro” is now a Gibson trademark but is used generically for any wood-body spider-bridge square-neck resonator.
Should I get a round-neck or a square-neck?: Depends on the music. Round-neck plays like a regular guitar — fingerstyle, flatpick, or bottleneck slide on a finger; great for Delta blues, acoustic blues, and standard-tuned fingerstyle. Square-neck has a raised nut and is played flat on the lap with a steel bar in open G — the bluegrass dobro setup. You cannot easily switch a square-neck to round-neck or vice versa.
Are resonators acoustic or electric?: Acoustic. The cone is a passive mechanical amplifier — no electronics. Many modern resonators add an internal pickup or microphone for stage use, but the cone itself is purely acoustic.
What tuning is the standard for a Dobro?: Open G high: G–B–D–G–B–D (low to high). The whole instrument forms a G major chord at the open position, which is exactly what you want under a steel bar — the bar functions as a movable barre across all six strings.
Do I need a slide to play a resonator?: Not always. A round-neck resonator can be played with fingers alone (in standard tuning or open tunings), with a flatpick, or with a slide. A square-neck resonator needs a steel bar — you cannot fret it with your fingers because the nut is raised. Many resonator players use both round-neck fingerstyle and slide.
Why is a metal-body resonator so much louder than a wood one?: Two reasons. First, metal bodies don’t absorb cone vibration the way wood does — the cone’s energy is reflected outward more efficiently. Second, the National biscuit-cone design itself is more efficient than the Dobro spider-cone design — less mass on the cone’s apex, faster response. The combination is what gives a Style O National its legendary cutting power.