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
Dropped A tuning result, it uses the same fingering as drop D tuning and drop C tuning. An alternate dropped A tuning utilizes a guitar tuned to E Standard with the 6th string dropped to a low A, resulting in AADGBE with the 6th and 5th strings an octave apart. Another variation of this tuning is AEADGB, which imitates a 7 on a six-string, excluding the high E. Another dropped A tuning is AGCFAD ("drop perfect fourth in the key of the D", i.e. whole guitar is tuned down one step, then the lowest string is dropped to A). Dropped A tuning Dropped