Simplify the following text for a Grade 6 native English-speaking person.
Original: Howard Dwaine `` Howie '' Dorough ( born August 22 , 1973 ) is an American musician and the oldest member of the Backstreet Boys since Kevin Richardson left in 2006 .
Simplified: Howard Dwaine Dorough ( born August 22 , 1973 ) , also known as Howie D , is an American singer . He was a member of the boy band Backstreet Boys .