The guitarrón mexicano, which means "big Mexican guitar" in Spanish (the suffix -ón in Spanish is used to make a word mean "big" or "large"), is a very large, deep-bodied Mexican six-string acoustic bass guitar. It is traditionally played in Mariachi groups. Although it looks similar to a guitar, it was not developed from the guitar. Instead, it was created separately from the sixteenth-century Spanish instrument called the bajo de uña ("fingernail-plucked bass"). Its large size allows it to produce loud sounds, so it does not need electric amplification for performances in small places. The guitarrón has no frets and uses heavy strings, usually nylon for the top three strings and wound metal for the bottom three. It is often played by repeating notes an octave apart, a practice made easier by its standard tuning: A1, D2, G2, C3, E3, A2. Unlike a guitar, the pitch of the guitarrón's strings does not always increase as the strings go downward. For example, the lowest string (A2, which is the sixth string) is a perfect fifth below the string next to it (E3). The guitarrón inspired Ernie Ball to create the first modern acoustic bass guitar, which was sold in 1972.

Use

The guitarrón is a large instrument used in Mexican Mariachi groups. These groups usually include at least two violins, two trumpets, one Spanish guitar, a vihuela (a five-string, high-pitched guitar-like instrument), and the guitarrón. A strap is often used to hold the instrument up so it can be played easily. The guitarrón is the main rhythm instrument in the group and acts as the bass instrument, producing deep sounds. The rhythm created by the basslines on the guitarrón helps the other instruments stay together. Most groups have only one guitarrón player.

To play the guitarrón, musicians need strong left hands to press down the thick strings onto the fingerboard. The right hand, especially the index, middle finger, and thumb, must be strong to pluck the heavy strings (usually a metal and a nylon string). The right hand typically plucks two strings at a time to play the bassline in octaves, even though the music is written as a single note. Because the strings are thick, the player must stay on or slightly ahead of the beat. The instrument plays basslines that move through the chord changes using rising and falling patterns. Three-note chords are often used in songs. The guitarrón also plays more detailed lines to add style to musical changes in key, rhythm, or speed.

• Mexican composer Julián Carrillo changed the guitarrón to play smaller musical steps by adding extra frets. He used the instrument, called the octavina, in several compositions, including the Preludio a Colón (1922).
• The guitarrón was played by Roy Estrada on the 1966 album Freak Out! by the Mothers of Invention.
• Randy Meisner of the Eagles played the guitarrón on the song "New Kid in Town" from the album Hotel California (1976; the instrument was called "guitarone" in the credits).
• Aaron Goldsmith, a member of the group Luminescent Orchestrii, uses a modified guitarrón with a longer neck to play melodies.
• Simon Edwards played the guitarrón for the 1980s band Fairground Attraction. He also played it on the Talk Talk album Spirit of Eden (labeled "Mexican bass" in the liner notes).
• Conrad Lozano often plays the guitarrón with his band Los Lobos.

Design

The back of the guitarrón is made from two pieces of wood placed at an angle, creating a shallow V shape. This design makes the instrument larger and deeper. The curved shape helps the instrument produce a strong, deep sound. The sides and back are made from Mexican cedar, and the top is made from tacote, a wood that is light but strong. Tuning machines with worm gears are used to change the tension on the strings, which allows the instrument to be tuned properly.