Slap bass is a bass technique once considered unusual, but one that is being employed by more and more mainstream bass guitarists. The technique dates back to the invention of the electric bass. Almost as soon as Leo Fender introduced the innovative Fender Precision Bass guitar, jazz and soul players began to explore the sounds the new instrument could make.
One of these sounds involved not plucking or picking the strings, but slapping them with the thumb, which produces a round, warm tone now associated mostly with funk music. In fact, it was Larry Graham who initiated the technique while jazz fusion and funk bass players of the 1960s and 1970s, such as Bootsy collins and Stanley Jordan—among others, made the technique popular.
In order to play slap bass, a bass player must think like a drummer –that is, to hit the strings with the thumb to get the right tone, the wrist must rotate in the same way a drummer’s wrist does when playing the traditional, or jazz, grip.
Writing in the book 101 Bass Tips, educator Gary Willis suggests digging around your garage, shed, or basement for a length of pine two-by-four on which to practice. That’s right, two-by-four. Apparently, Willis says, the pine is resonant enough that you will start to hear the slap tone as you play the wood like a percussion instrument with your thumb. And its width is just about right to cover the width of the strings on your guitar. If anybody asks, you’re building a dividing wall!