What Is a Resonator Guitar?

by Alasdair Smith

Resonator guitars have been produced since the early part of the 20th century and were popularized by many of the great early blues musicians. Resonator guitars have remained popular with many contemporary guitarists, including Dire Straits' Mark Knopfler and Ray Davis of the The Kinks, because of their distinctive tone. Several types of resonator guitar construction leads to an interesting range of tones and sound.

What is a Resonator?

A resonator is a metal or wooden bodied guitar that features one or more spun metal cones, or resonator discs, built face down in to the face of the body. The guitar strings run across a bridge attached to the apex of the cone, which then acts as an acoustic amplifier for the guitar. The additional volume derived from resonator guitars makes them an excellent choice for musicians playing live without amplification, while their unique metallic sound makes them stand out from other instruments. Resonator guitars were invented by John Dopyera in 1927 in an attempt to create a louder instrument to compete with other instruments.

Resonator Guitar Neck Styles

Resonator guitars can be classified by the type of neck they have -- round or square. A round neck is the kind of construction common to other guitars, but a square neck has a flat profile on the reverse. Square neck resonators are played with the guitar lying flat across the player's lap. This style of guitar playing is commonly seen in bluegrass musicians. Traditional round-neck styles are fretted and played in the normal manner, although many musicians reserve them for slide-guitar where the notes are played on the neck using a glass bottle-neck or length of metal pipe.

Resonator Body Construction

The most recognizable resonator guitar is the steel bodied version that many will know from the cover of Dire Straits album "Brothers in Arms." These guitars were developed by National Resophonic Guitars and original instruments like the 1937 model on the Dire Straits cover are valuable. Wooden-bodied resonators were developed by John Dopyera when he quit the National company and established Dobro. The wooden body helps deliver a less harsh tone with a smoother overall sound.

Resonator Cone Designs

The simplest resonator design is constructed from a single large cone, with what is often called a "biscuit-bridge" attached to the apex of the cone. The cone is built in to the body of the guitar and the strings run over the bridge. The single cone construction delivers a strident sound with less tonal complexity because the string vibration is transferred to a single point on the cone. The later tri-cone design features three smaller cones, joined by a T-shaped bridge assembly. The sound from the strings is distributed among the cones and reverberates within the body to create a warmer, richer tone. The spider-bridge and cone was developed for the first Dobros. The cone features a W-profile with a complex assembly resembling a spider web that connects the central apex of the W to the outer edges. This distributes the sound to various points, creating a rounder tone which is also more directly projected outwards.