premise: Still Waters Sinfo-Nia is a predominantly African-American youth orchestra located in Atlanta, Georgia, United States. It was originally called the William Grant Still Memorial Orchestra. The organization was started in 1990 and has been led by David E. Robinson III.
hypothesis: The William Grant Still Memorial Orchestra last performed in 1990 before changing its name to Still Waters Sinfo-Nia.
reason: The article doesn't say which year the name was changed.