Instrument types or tunings used for this purpose include basses with fewer than four strings ( one-string bass guitars , two-string bass guitars , three-string bass guitars ( tuned to E-A-D ) ) alternative tunings ( e.g. , tenor bass , piccolo bass , and guitar-tuned basses ) .
A bass guitar ( also called an `` electric bass '' or `` bass '' ) is a string instrument which is related to the electric guitar .