The resonator guitar, often referred to as dobro, is an instrument whose names are frequently used interchangeably. However, a resonator guitar refers to a broader category of guitars that includes the dobro. To better understand the relationship between the dobro and resonator guitars, it is essential to delve into their history.

Invented and popularized in the United States, the resonator guitar is classified under number 321.322 in the Horbostel-Sachs system, belonging to the composite chordophones category with parallel strings and plucking technique. It is part of the long-neck lute family and is often confused with a classical guitar due to its shape and size.

One key note: the reason the resonator guitar is also called a dobro stems largely from legal matters. The Gibson Guitar Corporation registered this type of instrument under the dobro name, promoting it through an extensive marketing campaign that led enthusiasts to associate this name with resonator guitars. Only chordophones produced by Gibson can be called dobros. These instruments feature a distinctive spider bridge, unique to Gibson, which gives the guitar a sharper sound and enhances the guitarist’s performance.

History of the Resonator Guitar

Since the early days of music, the guitar has been considered the quintessential instrument. Due to its relative ease of play and exceptional potential, this title is well-deserved. At the beginning of the 20th century, musicians sought new methods and styles to create originality, distinguish themselves, and outperform rival artists or bands in the same genre. However, the acoustic guitar proved inadequate for this purpose.

From 1910 onwards, modern musicians began favoring playing in ensembles, which classical or acoustic guitars of the time could not adequately support. These guitars were often overshadowed by mandolins, which produced a louder and more varied sound. To address this need, the Dopyera brothers—Czechoslovak immigrants to the United States—began working on what would become the first model of the resonator guitar.

Once created, the instrument spread rapidly across the United States, even reaching Hawaii, where it gave rise to the traditional lap steel guitar, a unique playing style involving horizontal positioning of the guitar and a metal slide. The instrument’s popularity soared, prompting the Dopyera brothers to establish the National String Instruments Corporation in Los Angeles in 1928, introducing the spider bridge, now a key component of resonator guitars.

One of the brothers invented the tricone resonator, featuring a spider bridge with three resonators. Made from German Silver, a metal alloy, this type of guitar initially gained popularity in Hawaiian music after being patented.

During the 1930s economic crisis, the number of resonators was reduced to one, the single cone, also called the biscuit, which one of the brothers, Beauchamp, patented under his name. The brothers left the company and founded the Dopyera Brothers Manufacturing Company, later suing Beauchamp and winning the case in 1933.

The two companies merged, forming National-Dobro, but the advent of electric guitars led to its closure. After World War II, some brothers created DB Original to produce triple-resonator dobros.

Over time, companies like O.M.I. and Hound Dog emerged, until Gibson acquired the dobro trademark in 1993.

Today, dobros or resonator guitars have largely been replaced by amplified electric instruments, which address issues of weight and handling. However, classic models remain appreciated, particularly for collectors and in performances that celebrate American or Hawaiian traditions, the latter being the adopted home of resonator guitars.

How the Resonator Guitar is Made

The resonator guitar features a body made of maple or mahogany with a fingerboard of rosewood or ebony. At first glance, it closely resembles traditional guitars. What sets it apart is the presence of a resonator inside the soundbox. Structurally, this component can be considered a type of speaker, an amplification system made from high-quality aluminum.

The resonator is set into vibration by the strings, which rest on a bridge near the cone’s apex. This produces the characteristic reverberating sound. The soundbox retains traditional shapes but is constructed from metal for added durability. This gives the guitar a loud, metallic tone. The reverb effect is particularly noticeable in mid frequencies and shines during arpeggios. Unsurprisingly, it has become the hallmark instrument of American country music.

How to Play a Resonator Guitar

Playing a resonator guitar does not require additional knowledge beyond the basics necessary for a standard guitar. The fingering and use of a pick are the same. The main differences are the dobro’s heavier weight and the need for precise tuning to prevent the reverb effect from distorting the sound.

Once you hold the instrument, rest it on your right leg using the small notch on the soundbox. Place your left hand on the fingerboard and your right hand on the soundbox to pluck the strings. For more insights into the dobro’s unique features, check out the following video.

Types of Dobros or Resonator Guitars

While this model is standardized, the dobro has been released in various configurations since its creation, specifically three main types.

Tricone Resonator Guitar

This type of dobro features three small T-shaped cones on the soundbox, above which sits a wooden bridge supporting the strings. It was the first resonator guitar model created and is now prized more as a collector’s item than for practical use.

Single Cone Dobro with Biscuit Bridge

To increase production and reduce costs, National developed the biscuit-bridge resonator guitar. It features a rounded tip pointing toward the strings, with a small ring supporting the bridge. Its characteristic sound and affordable price made it popular in folk music, particularly acoustic blues.

Resonator Guitars with Spider Bridge

The spider-bridge resonator guitar is the most well-known and widely used model today, becoming synonymous with this type of instrument. It features a cone pointed toward the center of the guitar, just above the soundbox, with a metal bridge resembling a spider web. This design produces a sound beloved in country music. In Italy, artist Ligabue is one of its most famous proponents, using the instrument’s reverb effects in many of his successful albums.