The fretless bass has a very distinctive sound. Whether it’s a fretless electric bass or a traditional upright double bass, there’s something about its sound that marks it out clearly from a normal bass guitar. What is it?
There is one big factor: the lack of frets!
To understand the significance of this you must understand why bass guitars have frets at all.
Why do bass guitars have frets?
The purpose of frets on a guitar (electric or bass) is to help the player pitch their notes. In theory the strings can produce any pitch on a wide range, not just the “note” pitches we would write on a musical score. The frets ensure that if the player wants to play, for example, an A note they actually produce an A rather than a pitch slightly higher or lower.