Along with tuners, string winders, humidifiers, and other accessories, the capo is one of the more popular acoustic and electric guitar add-ons. A capo, whose name derives from the Italian for “head,” is a tiny instrument that clamps onto a guitar’s neck to shorten the strings’ length and raise their pitch. The majority of the time, a capo is used on all the strings of a guitar or other fretted stringed instrument. However, this is less frequently the case.
The fundamental benefit of employing a capo is that it enables a guitarist to use first-position open-string chord forms, which have a more droning and completely resonant tone than, for instance, many bar chords, while playing a song in several keys.
You must first comprehend what the nut does in order to comprehend what the capo performs. The nut, a small strip of plastic, metal, or bone, marks the end of a string’s vibrating length (or scale length) on the headstock end of a guitar. As the strings leave the fretboard and locate their anchor points on the headstock, they cross the nut that spans the seam where the fretboard meets the headstock (typically at an angle). The bridge at the body end of the scale length and the grooves in the nut work together to maintain the proper lateral alignment of the strings down the length of the fretboard.
A capo can be attached to any fret below the neck joint and provides the same kind of vibration termination, acting as a sort of movable nut. Capos, however, lack the string grooves of the nut since their only function is to modify pitch rather than to preserve lateral string positioning (a function still ensured by the nut and bridge even when a capo is in use). Thus, a capo complements the nut rather than replacing it.
Capos have a crucial distinction that is worth noting: they are used to alter the pitch of open strings without modifying the tuning keys. Accordingly, only the pitch of the open, unfretted strings changes; the pitch of notes that are fretted does not. As a result, the strings’ timbre as well as pitch are impacted, contributing to the tonality of instruments with shorter scales, like mandolins.
A variety of capos styles are attached to a guitar neck right behind the fret wire using a variety of attachment techniques. The strings are really held down by a rubber-covered bar that is secured to the neck with an elastic, nylon, or other fabric strap or by a spring, screw, or cam-operated clamp on the majority of instruments.
A relatively modern invention is the partial capo, which only covers two, three, four, or five strings instead of all six and does not entirely encircle the neck. Numerous tone alterations are thus possible without having to adjust the instrument’s tune.
Blues, folk, flamenco, and traditional Irish guitar music frequently employ capos; jazz and classical guitar rarely do. George Harrison, Keith Richards, Noel Gallagher, Bruce Springsteen, Steve Earle, Tom Petty, Richard Thompson, Johnny Marr, Paul Simon, Jimmy Page, John Mayer, and several more rock and pop musicians have all utilised capos.