Simplify the following text for a Grade 11 native English-speaking person.
Original: Everman left immediately after Soundgarden completed its promotional tour for Louder Than Love in mid-1990 to play bass for the band OLD ( Old Lady Drivers ) and Soundgarden found Yamamoto 's ultimate successor , bassist Ben Shepherd .
Simplified: Later in 1990 , Everman left the band and Soundgarden found Yamamoto 's ultimate successor , bassist Ben Shepherd .