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
Jazz violin symphonic approach to jazz fusion made him a popular fusion artist of the 1970s. In 1972, he featured prominently on Elton John's "Honky Chateau" album. In 1977, he pioneered the use of the 5-string electric violin, with a lower C string. He sometimes also uses a 6-string electric violin called the Violectra, with low C and F strings – not to be confused with the violectra he played from the late 1960s to the mid-80s which had 4 strings, but tuned an octave lower. Ponty was among the first to combine the violin with MIDI, electronic distortion boxes, phase shifters,