Sentence examples for bass line from inspiring English sources

"bass line" is correct and usable in written English.
This phrase can refer to the line played by a bass guitar, usually serving as the foundation for a song, or it can refer to the line of the lowest part in a musical ensemble, like the basso continuo in Baroque music. For example, in a concert review, you could write "The bass line laid the foundation for an exciting and energetic performance."