There are multiple artists with this name:
1) Set It Off is a band from Tampa, Florida, formed in 2008. Members include: Cody Carson (vocals, guitar), Zach Dewall (guitar, vocals), Austin Kerr (bass, vocals), Maxx Danziger (drums) and Dan Clermont (synth, vocals).
Cody started the band after singing "Coffee Shop Soundtrack" on stage with All Time Low.
2) Set It Off are an alternative rock band from somewhere in Gloucestershire, England. They formed in late 2006 and have with funk and electronica influences.
Vocals and Guitar - Joe Milnthorpe
Bass and Guitar - Pete Lee
Guitar and Bass - Tim King
Drums - Nik Powis
3) Set It Off were a hardcore punk band from Oslo , Norway, active between 1998 and 2003. Members: Jonathan - Vokals (LeftAmongTheLiving,Aggravation, ShotAtDawn) Jonas - Drums (Kraanium, LeftAmongTheLiving, Whip) BT2000 - Guitar (LeftAmongTheLiving, SheSaidDestroy) Markus - Bass (Cochise) Rolf H - Guitar Snorre - Live Guitar (SheSaidDestroy,LeftAmongTheLiving)