[3] The quartet first appeared on the sixth season of Mnet's talent show series Superstar K under the name North Incheon Nineteen.

[5] A portmanteau of the words "voice" and "whisper",[3] its formation was announced on February 16, 2016, with a tentative debut towards the end of the month.

[10] Voisper participated in the music competition series Immortal Songs: Singing the Legend, making its first appearance covering Kim Jong-chan's "You're Crying Too" on February 25, 2017.

[3] Its debut single "In Your Voice" is an R&B song that consists of a "dreamlike" melody, accompanied by a "sweet" piano and "powerful" drum.

[8] On Voice + Whisper, the record opens with the dance track "On & On" , which incorporates modern rock and electronic music into its sound.

American boy group Boyz II Men, Jung Dong-ha, and Kim Bada were also highlighted as inspirations.