This channel mostly contains Christian hymns (chorale style); 4 part SATB choir arrangements, also available on my website and all very suitable also to be sung as 4 part a cappella. I even prefer the latter, or at least the accompaniment should always adjust to the (4-part) singing of the choir/congregation, not the other way around. I consider 4 part singing important, preferably also by the congregation itself, not just the choir, because then one really can sing in utmost harmony and praise God in one's own range, which suits one best, and which is not the case with singing in unison. Romans 15:5-6 and more verses like in the Bible do not mean that the Bible tells us to sing in unison. The greatest harmony creates the greatest unison among people, so that one really unitedly can honor the Lord with one voice and one heart. Sorry John Calvin, it was the other way around. Singing in 4 part harmony creates way more unity and harmony than singing in unison. Soli Deo Gloria (SDG).