Mandolin are used. Usually, courses of 2 adjacent strings are tuned in unison. By far the most common tuning is the same as violin tuning, in scientific pitch notation G–D–A–E, or in Helmholtz pitch notation: g–d′–a′–e″. Note that the numbers of Hz shown above assume a 440 Hz A, standard in most parts of the western world. Some players use an A up to 10 Hz above or below a 440, mainly outside the United States. Other tunings exist, including "cross-tunings", in which the usually doubled string runs are tuned to different pitches. Additionally, guitarists may sometimes tune a mandolin to
New standard tuning Fripp suggested that Guitar Circle members experiment with an A String (0.007) from Octave4Plus of Gary Goodman; if successful, the experiment could lead to "the NST 1.2", C2G2D3A3E4-A4, according to Fripp. In 2010, Fripp suggested renaming the tuning as "Guitar Craft Standard Tuning or C Pentatonic tuning". The lowest five strings are tuned in perfect fifths from a low C. The first string is a minor third up from the E to a G. Since the lowest five strings are tuned in fifths, guitars with NST can be played with the fingerings for chords and scales used on the violin,