The Guitarrón is a large bass guitar (hence: Guitarrón means large guitar -- suffix ón means big or large). It has 6 strings - 3 that are nylon wound with a nylon monofilament core or nylon fibers, and 3 that are steel, bronze or copper wound with a single steel string core. The following could serve as a guide to the gauge of each string (from 6th to 1st):
6- A ( .098 ) STEEL/BRONZE WOUND
5- D ( .075 ) STEEL/BRONZE WOUND
4- G ( .055 ) STEEL/BRONZE WOUND
3- C ( .105 ) NYLON WOUND
2- E ( .070 ) NYLON WOUND
1- A ( .055 ) NYLON WOUND
The sound produced by pulling the strings is loud and powerful. This sound has a distinctive timbre (tæm-bər) quality that is warm and colorful. The large hollow-body, with the convex back, enhances the lower frequencies thus producing a rich bass sound. The fingerboard (el díapson) is fretless and the tuning mechanism can be metal machine heads or wooden pegs (the wooden pegs are called las clavijas). The strings are of heavy gauge and the tension is firm. A very special and specific left hand technique is required to depress the strings. Support, clarity and intonation are essential when producing the desired notes being played. Left hand strength would be desirable but not necessary. The right hand is used for plucking or pulling (el jalón) two strings simultaneously near the sound hole of the Guitarrón. When the two strings are played together for each written note, they are played in octaves. Pulling on a single string instead of double stringing can also produce warmth and color of the notes being played. The fretless fingerboard is used to depress the string (to stop) with the fingers in certain positions thus producing the notes desired.
The role of the Guitarrón functions as the backbone of the mariachi ensemble. It provides the bass line, the primary rhythmic pulse and primary musical guide along with the Vihuela Mexicana and the guitar. These instruments together are commonly referred to as the rhythm section or las armonías. It is interesting to note that the Guitarrón eventually replaced the harp as a bass instrument. The Guitarrón was the instrument preferred by the mariachi musicians in central Jalisco.