Editing Eight-string guitar (section)

==Designs==

===Semi-acoustic guitar (hollow-body guitar)===
{{See also|Semi-acoustic guitar|Archtop guitar}}

Seeking a [[guitar tuning]] that would facilitate jazz [[improvisation]], [[Ralph&nbsp;Patt]] invented [[major-thirds tuning]] in 1963.<ref name="Griewank1" >{{harvtxt|Griewank|2010|p=1}}</ref><ref name="Kirkeby">{{cite web|first=Ole|last=Kirkeby|date=1 March 2012|title=Major&nbsp;thirds tuning|url=http://v3p0.m3guitar.com/|publisher=m3guitar.com|archive-url=https://web.archive.org/web/20150411064851/http://v3p0.m3guitar.com/|archive-date=11 April 2015|id=cited by {{harvtxt|Sethares|2011}} and {{harv|Griewank|2010|p=1}}}}</ref><ref name="Patt">{{cite web|url=http://www.ralphpatt.com/Tune.html|first=Ralph|last=Patt|publisher=ralphpatt.com|work=Ralph&nbsp;Patt's jazz web page|title=The major&nbsp;3rd tuning|date=14 April 2008|access-date=10 June 2012|id=cited by {{harvtxt|Sethares|2011}} and {{harvtxt|Griewank|2010|p=1}}}}</ref> Patt's tuning is a [[regular tunings|regular tuning]], in the sense that all of the [[interval (music)|interval]]s between its successive [[open string (music)|open string]]s are [[major third]]s; in contrast, [[standard guitar tuning]] has one major-third amid four [[perfect fourth|fourth]]s.<ref name="Sethares2001">{{harvtxt|Sethares|2001}}</ref>

[[Seven-string guitar]]s are needed for major-thirds tuning to have the E-e' range of the standard tuning.<ref name="Sethares2001"/><ref name="Peterson37">{{cite journal|title=Tuning in thirds: A new approach to playing leads to a new kind of guitar |first=Jonathon |last=Peterson |location=Tacoma WA|url=http://www.luth.org/backissues/al69-72/al72.htm |journal=American Lutherie: The Quarterly Journal of the Guild of American Luthiers |publisher=The Guild of American Luthiers |issn=1041-7176 |volume=72 |date=Winter 2002 |access-date=9 October 2012 |pages=36–43 ] |url-status=dead |archive-url=https://web.archive.org/web/20111021185726/http://www.luth.org/backissues/al69-72/al72.htm |archive-date=21 October 2011 }}{{rp|37}}</ref> Having an eight-string instrument allowed Patt's guitar to have G{{music|sharp}} ([[enharmonic equivalency|equivalently]] A{{music|flat}}) as its [[open note]].<ref name="Peterson37"/> Patt purchased six-string [[archtop guitar|archtop]] [[semi-acoustic guitar|hollow-body guitar]]s that were then modified by luthiers to have wider necks, wider pickups, and eight strings. Patt's Gibson ES-150 was modified by Vincent "Jimmy" DiSerio c. 1965.<ref name="Patt"/><ref name="Peterson37"/> Luthier [[Saul Koll]] modified a sequence of guitars: a 1938 Gibson Cromwell, a Sears Silvertone, a c. 1922 Mango archtop, a 1951 Gibson L-50, and a 1932 Epiphone Broadway; for Koll's modifications, custom pick-ups accommodated Patt's wide necks and high G{{music|sharp}} ([[enharmonic equivalency|equivalently]] A{{music|flat}});<ref name="Peterson37"/> custom pick-ups were manufactured by [[Seymour&nbsp;Duncan]]<ref name="Peterson37"/> and by Bill&nbsp;Lawrence.<ref name="Patt"/> Roy Connors, former member of the 1960s folk singing group, [[The Highwaymen (folk band)|The Highwaymen]], reconfigured a Martin O-28 six-string guitar to an eight-string of his own design and received a U.S. Patent on it (#3269247).

===Solid-body===
Solid-body eight string guitars are also used by many bands today. The construction of a solid-body eight-string guitar is comparable to that of seven- and six-string variants. The standard tuning (from low to high) is F{{music|#}}, B, E, A, D, G, B, E.<ref>{{Cite web|url=http://www.guitarcasa.com/2014/02/17/8-string-guitar-tuning/|title=8 String Guitar Tuning - All You Need To Know!|website=GuitarCasa.com|access-date=19 April 2021}}</ref> Many prefer to tune the F{{music|#}} to a low E (E1), the same note as the lowest string on a four-string [[electric bass]] in standard tuning, and providing the guitar with a fuller sound by having three different E strings.<ref>{{Cite web|date=2020-10-08|title=List Of Most Common 8 String Guitar Tunings - Guitar Lessons|url=https://pickuptheguitar.com/list-of-most-common-8-string-guitar-tunings/|access-date=2021-02-03|website=Pickuptheguitar.com|language=en-us}}</ref> This tuning is equivalent to tuning a six-string guitar to [[Drop D tuning]].

Like the seven-string, the first mass-produced eight-string guitar was made by [[Ibanez]] guitars in Japan; the [[RG2228]]. {{fact|date=July 2018}}

===Scale length===
The main design issue faced with an eight-string guitar is tuning stability with the lower strings. This is due to the neck being constructed too short, bridge problems such as improper intonation, uneven spacing for floating bridges, or the use of wrong string gauges. Other problems associated with tuning stability rely on the proper setup of the guitar.

Extended range eight string guitars sometimes will have a [[multi-scale fingerboard|multi-scale]] design where the bass strings will be longer than the treble strings (fanned fret design). This helps with proper [[Intonation (music)#Fretted instrument intonation|intonation]] of the lower strings, improves string tension balance across the strings, improves [[Guitar harmonic#Overtones|harmonic overtones]], [[overtone series]], and improves [[inharmonicity]]. (See also [[Piano acoustics#Inharmonicity and piano size|inharmonicity in pianos]]). The bass strings on an 8 string typically require the saddle to be pulled back a bit more than the other strings to properly set the intonation. Some bridge designs accommodate this by offsetting back the 7th and 8th strings or providing a bit extra room for adjustment. Longer scale lengths require less offset for proper intonation. {{fact|date=May 2017}}