Open C tuning is an open tuning for guitar. The open-string notes form a C major chord, which is the triad (C,E,G) having the root note C, the major third (C,E), and the perfect fifth (C,G). When the guitar is strummed without fretting any strings, a C-major chord is sounded. By barring all of the strings for one fret (from one to eleven), one finger suffices to fret the other eleven major-chords.
There are several open C tunings.
The English guitar uses a repetitive open-C tuning
C-E-G-C-E-G,which is approximately a major-thirds tuning,[1] specifically
C-E-G-C-E-G=C-E-A-C-E-A.
This open C tuning was used by Soundgarden for songs including Pretty Noose, Burden in My Hand, and Head Down. Chord sequences often omit the high E string, leaving the power chord ubiquitous to Grunge music.[2]
C-G-C-G-C-E.[3] This open C tuning was used by William Ackerman for his "Townshend Shuffle", by John Fahey for his tribute to Mississippi John Hurt, and by Led Zeppelin's Jimmy Page for "Friends".[4] [5] It is also used by Devin Townsend for the vast majority of his work (The Devin Townsend Project, Strapping Young Lad, Casualties of Cool).[6]
C-C-G-C-E-G[7]
Another open C tuning uses the harmonic sequence (overtones) of the note C. When an open-note C-string is struck, its harmonic sequence begins with the notes (C,C,G,C,E,G,B,C). The root note is associated with a sequence of intervals, beginning with the unison interval (C,C), the octave interval (C,C), the perfect fifth (C,G), the perfect fourth (G,C), the major third (C,E), and the minor third (E,G); in particular, this sequence of intervals contains the thirds of the C-major chord .[8]
C-C--G-C-E-G
Many of the notes from the harmonic sequence for C appear in the new standard tuning (NST),[9] which is a nearly regular tuning based on perfect fifths; NST also has (D,A) from the pentatonic scale on C:
C-G-D-A-E-GNST is used in Guitar Craft (a school of guitar playing founded by King Crimson's Robert Fripp). The open-C overtones tuning has the same range as NST, which can use extreme strings (.011 and .059 inches).[10]
C-C-G-C-E-C
Using a high C rather than the high G of the overtone series, this open C tuning was used by Mick Ralphs for the songs "Can't Get Enough" and "Movin' On" on Bad Company's debut album. Ralphs said, "It needs the open C to have that ring," and "it never really sounds right in standard tuning".[11]
Book: Persichetti, Vincent . Vincent Persichetti . Twentieth-century harmony: Creative aspects and practice . 1961 . W. W. Norton . New York . 0-393-09539-8 . 398434 . registration .