Roughly 2015 - 2017, Haven joined hardcore band Proclaimer, where he played bass and sang clean vocals. In 2016, Haven recorded, mixed, mastered and co-produced Proclaimer's first EP - Legacy. In 2017, the band began work on a second EP - False Prophet, also recorded, mixed, and co-produced by Yates.
In April 2017, Yates jumped on an opportunity to audition for The Voice, while Proclaimer went on their first tour without him. Seeing this as a sign of things to come, Yates announced to the band he would be stepping down to pursue his solo career. Yates and Proclaimer quickly found a replacement bass player, and Yates continues to collaborate with the band producing shows, recordings, etc.