Capo plays a B note for any capo position at or below the seventh fret), and thus a performer does not need to adjust for or relearn the entire fretboard as they might with retuning. The scale length of the strings of an instrument affects the timbre of the strings, and thus the use of a capo may alter the tone of the instrument. Musicians also use capos to bring a guitar tuned below standard up to standard tuning. Manufacturers sometimes recommend tuning a twelve-string guitar a whole-step or more below standard to offset the additional stress of the additional strings.
String harmonic and bridge pickups sound different. If a node is directly over a pickup, little or no sound is heard. This technique was popularized by Eddie van Halen. Tapped harmonics are an extension of the tapping technique. The note is fretted as usual, but instead of striking the string the excitation energy required to sound the note is achieved by tapping at a harmonic nodal point. The tapping finger bounces lightly on and off the fret. The open string technique can be extended to artificial harmonics. For instance, for an octave harmonic (12-fret nodal point) press at the third fret, and