The first 8 string bass guitars were made by Hagstrom, from 1967 to 1969 with a total of 2,249 being manufactured. An 8 string bass guitar is strung with paired, octaved strings, similar to those of a regular 12 string guitar. Standard tuning is usually as so:
8 string basses are usually fretted, however fretless 8 string basses have been known to exist, though would usually be a custom make. Though once rare, many well-known guitar manufacturers now make 8 string basses commercially available, such as ESP Guitars, Dean Guitars, Hamer Guitars, Washburn Guitars, and Hagstrom among others.
Often, the 8 string bass guitar is played with a plectrum so to have a better attack and to increase the 'ringing' of the higher-register strings, but is not essential. Many funk players have used finger and slap and pop techniques with the 8 string bass (such as Victor Wooten). Some other bassist of note who have utilised the 8 string bass are Jeff Ament of Pearl Jam, Paulo Pinto of Sepultura, John Paul Jones of Led Zeppelin, John Entwistle of The Who, Mike Rutherford of Genesis, and Tom Petersson of Cheap Trick (who is known as the inventor of the 12 string bass). Guitarist Jimi Hendrix also played 8 string bass on tracks from his Electric Ladyland album, namely "Crosstown Traffic" and "1983... (A Merman I Should Turn to Be)".
10 string basses incorporate a high b and low B string (like that of a regular 5 string bass, but double stringed). Dean Guitars perhaps make the most affordable commercially available 10 string bass.
The first known 12 string bass guitar the "Hamer Quad" was built in 1978 by Hamer Guitars. 12 string basses with a high c and low C (like that of a standard 6 string bass) are most often expensive custom order from specialists luthier. Commercially available 12 string basses such as those from Hamer Guitars and Dean Guitars are strung in triples such as:
Bassists of note who have utilised the 12 string bass guitar are Jeff Ament of Pearl Jam, Billy Sheehan of Mr. Big, Frank Bello of Anthrax, Jason Newsted of Metallica, Tom Petersson of Cheap Trick, Doug Pinnick of King's X, Eric Brittingham of Cinderella, Tim King of SOiL and Chris Squire of Yes, who often tunes his Raney 8-string bass eE-aA-aD-dG, so that notes played on the upper two courses sound as open fifths.
Fieldy from the nu-metal band Korn has used a 15-String bass in recording their latest untitled studio album, however non of the tracks were it was used made the final cut. It is a tripled five-string bass and was custom by Fieldy's longtime endorser Ibanez and called the K-15, in tradition with Korn's orther signature instruments the Ibanez K5 and the Ibanez K7.