What about the bass guitar?

The Electric bass guitar has been around since the 1920's when Lloyd Loar designed the first electric double bass and has become the standard bass instrument for popular modern music, and, through all its changes in design, remains the backbone of rock. As time goes on the electric bass guitar is becoming more and more popular. It has almost totally superseded the old upright acoustic bass. It provides the low-pitched bassline and bass runs in pop, rock and jazz. Bass players also do nifty solos in jazz, fusion, and latin music.
Bass Guitar Music