Double Bass,Piano,String Bass - Level 3 - Digital Download SKU: A0.851881 By Katy Perry. By Bonnie McKee, Dr. Luke, Henry Walter, Katy Perry, Lukasz Gottwald, and Max Martin. Arranged by Caroline McCaskey. Pop. Score and part. 12 pages. AltStrings #2072353. Published by AltStrings (A0.851881). This engaging, gig-ready arrangement of Roar is easy to read and fun to play! For solo Bass with Piano accompaniment.