Such guitars are not as common as the six-string variety, but are used by guitarists to modify the sound or expand the range of their instrument.
Some twenty years later, former Rollins Band guitarist Chris Haskett had a custom Paul Reed Smith nine-string guitar made in this configuration.
The inspiration for the design was supposedly the desire to capture the prominent tonalities of a 6/12 doubleneck on a single-neck guitar.
[citation needed] The second style expands on the seven- and eight-string guitar concept by adding either an additional lower- or higher-tuned string.
When a lower string is added, the standard tuning becomes C#, F#, B, E, A, D, G, B, E. The scale is often lengthened, e.g., on the Ibanez RG9 (712 mm/28" instead of the common 25.5").