Pentatonix (often abbreviated as PTX) is an American a cappella group of five vocalists originating from Arlington, Texas. The members are Scott Hoying (baritone lead/harmony), Kirstin Maldonado (mezzo-soprano lead/harmony), Mitch Grassi (counter-tenor lead/harmony), Kevin Olusola (tenor/ percussion), and Matt Sallee (bass). Avi Kaplan was formerly a member of the group; he was replaced by Sallee in 2017. Their work, mostly in, but not limited to, the pop music style, consists of covers of pre-existing songs and some original material, sometimes in the form of medleys.