Original: When music for bass clef instruments , such as the cello or trombone , goes several ledger lines above the bass clef , the tenor clef is used ; if it were to go even higher than practical in tenor clef , the notes may be notated in treble clef .
Simplified: Notes more than two or three leger lines below the treble clef stave or two or three leger lines above the bass clef stage are rarely used . It is usually easier to change the clef .