If you know how to read music, you're already familiar with the bass clef, also known as the F clef. Similar to how the treble clef allows you to notate musical notes in the upper registers, a bass ...

Spinal Tap's "All-Bass" sound ("Big Bottom"), taken and played seriously by jazzmasters. The Bass Clef Experiment is a creative collaboration between bassist Greg Gohde and cellist Mike Alvarez.

Hence, a bass player would use the bass clef, as they play lower pitched notes, where a guitarist would use the treble clef.