Watch the Open-String Technique & Exercises online guitar lesson by John Goldsby from Upright Bass Handbook
In this exercise, we'll concentrate on playing open strings. We'll go through five exercises that lay the foundation for getting a good sound.
To get a good, strong pizzicato sound on the bass, you need to use a bit of snap from your right hand wrist and finger. Get some of the meat of your right hand index finger on the string. Pluck through the string, moving your index finger down into the fingerboard. Focus on striking through the string. when your finger moves through the string, you should get on and off the string fast. Play through the string with a fluid motion, first out-of-time, and then in time.
I visualize a small circular motion with the right hand index finger. The slower the tempo, the larger the circle. The faster the tempo, the smaller the circle. Remember that the motion will make the sound. A strong, smooth, rhythmic motion will create a strong, smooth, rhythmic sound. When you play an open string, sometimes you need to mute the string with your right or left hand, in order to play the correct note length, or to move to a different string without the first string ringing too long. You can mute an open string with your left hand finger by lightly touching the string as it's ringing.
Play each exercise as slowly as you need to, or even out of time at first. Then practice the exercises in time at a slow tempo to get the feeling of plucking the string with your left hand index finger, then muting the string with your left hand. There are also situations where you'll mute the string with your right hand. Sometimes, either right or left hand can be used to mute a ringing string.