Colby Jeffers, who calls himself a “change maker rapper,” is giving a free concert at Haverhill’s Universalist Unitarian Church. The Phoenix native performs Friday, Sept. 19, from 7 to 9 p.m., at the church at 16 Ashland St., Haverhill. The concert is part of a national tour which started in Billings, Mont. Other stops include Hoboken, N.J., and Portsmouth, N.H.Jeffers’ Better World Concert promises a blend of conversation and community building along with the music.