Simplify the following text for a Grade 11 native English-speaking person.
Original: Notes below low E appear regularly in double bass parts in the Baroque and Classical eras , when the double bass was typically doubling the cello part an octave below .
Simplified: Notes below low E appear regularly in the double bass parts found in later arrangements and interpretations of Baroque music . These parts are transpositions of parts written for other bass instruments used before the modern double bass became common and may actually lower the part an octave .