Melody in music is nice. It gives the general idea of what the tune is, be it in singing or plain instrumental music piece. To give it life, though, you need something else. The bass. Even for a choir, that low tune for the men makes the song much more interesting. In a music band, you have the keyboard, the drums and the lead guitar. Without the bass, something is lacking.
It is not as easy as you hear it, unless you have musical genius to figure out how the bass tune sounds in a particular song or music piece. You have to learn it. One way to do that is to have your own instrument. Check the fender electric bass at Guitar Center.