 Elaborating about the song 's development in an interview for Sound on Sound Eriksen said , " I find that how natural it sounds is not so much about how realistic the string sound is , but more about your choice of notes and how you play and program the strings . " According to the sheet music published by Universal Music Publishing Group at Musicnotes.com , it was composed in the key of C minor using in common time and a slow feeling groove of 72 beats per minute . Rihanna 's vocal range spans from the low note of F # 3 to the high note of C # 5 . 
