- Tonal range: The addition of a low B string on a 5-string bass allows for a wider tonal range, especially for playing lower notes. This is particularly useful in rock music, where bassists often play with heavily distorted guitar tones and need a bass that can cut through the mix. Jazz music, on the other hand, tends to emphasize higher frequencies and more complex harmonic structures, so the extra low string may not be as necessary.
Source: Bass Player Magazine - "The Pros and Cons of 5-String Basses" (https://www.bassplayer.com/gear/the-pros-and-cons-of-5-string-basses)
- Technical ability: Playing a 5-string bass requires a certain level of technical proficiency, as it can be more difficult to navigate the wider neck and extra string. This may be more common among rock bassists, who often focus on technical proficiency and virtuosity in their playing. Jazz bassists, on the other hand, may prioritize a more laid-back and groove-oriented approach to playing, which may not require the same level of technical ability.
Source: Premier Guitar - "5-String Basses: Pros and Cons" (https://www.premierguitar.com/articles/5-string-basses-pros-and-cons)
- Tradition: Jazz music has a long history of using 4-string basses, and many jazz bassists continue to use them as a nod to that tradition. In contrast, rock music has a more diverse history of bass playing, and the use of 5-string basses has become more common in recent years as rock music has evolved and become more technically demanding.
Source: Reverb - "5-String Basses: A Comprehensive Guide" (https://reverb.com/news/5-string-basses-a-comprehensive-guide)
Overall, the reasons why more rock bassists use 5-string basses than jazz bassists can be attributed to factors such as tonal range, technical ability, and tradition. While there are exceptions to these trends, they provide a general explanation for the differences in bass playing styles between these two genres.