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Other tuning variations

A small number of bass players tune their strings in fifths, like a cello but an octave lower (C –G –D –A low to high). This tuning was used by the jazz player Red Mitchell and is used by some classical players, notably the Canadian bassist Joel Quarrington. Advocates of tuning the bass in fifths point out that all of the other orchestral strings are tuned in fifths (violin, viola, and cello), so this puts the bass in the same tuning approach. Fifth tuning provides a bassist with a wider range of pitch than a standard E–A–D–G bass, as it ranges (without an extension) from C to A. Some players who use fifths tuning who play a five-string bass use an additional high E string (thus, from lowest to highest: C–G–D–A–E). Some fifth tuning bassists who only have a four string instrument and who are mainly performing soloistic works use the G–D–A–E tuning, thus omitting the low C string but gaining a high E. Some fifth tuning bassists who use a five-string use a smaller scale instrument, thus making fingering somewhat easier. The Berlioz–Strauss Treatise on Instrumentation (first published in 1844) states that "A good orchestra should have several four-string double-basses, some of them tuned in fifths and thirds." The book then shows a tuning of E –G –D –A) from bottom to top string. "Together with the other double-basses tuned in fourths, a combination of open strings would be available, which would greatly increase the sonority of the orchestra."

In classical solo playing the double bass is usually tuned a whole tone higher (F ♯ –B –E –A). This higher tuning is called "solo tuning", whereas the regular tuning is known as "orchestral tuning". Solo tuning strings are generally thinner than regular strings. String tension differs so much between solo and orchestral tuning that a different set of strings is often employed that has a lighter gauge. Strings are always labelled for either solo or orchestral tuning and published solo music is arranged for either solo or orchestral tuning. Some popular solos and concerti, such as the Koussevitsky Concerto are available in both solo and orchestral tuning arrangements. Solo tuning strings can be tuned down a tone to play in orchestra pitch, but the strings often lack projection in orchestral tuning and their pitch may be unstable.

Some contemporary composers specify highly specialized scordatura (intentionally changing the tuning of the open strings). Changing the pitch of the open strings makes different notes available as pedal points and harmonics.A variant and much less-commonly used form of solo tuning used in some Eastern European countries is (A –D –G –C), which omits the low E string from orchestral tuning and then adds a high C string. The tololoche in Mexico (a smaller variant of the double bass) also uses the A-D-G-C tuning. Some bassists with five-string basses use a high C string as the fifth string, instead of a low B string. Adding the high C string facilitates the performance of solo repertoire with a high tessitura (range). Another option is to utilize both a low C (or low B) extension and a high C string.