“So the Levites appointed Heman the son of Joel; and of his brethren, Asaph the son of Berechiah; and of the sons of Merari their brethren, Ethan the son of Kushaiah;”
King James Version (KJV)
15:18 Second degree - The first rank of sacred musicians being thosethree famous persons named ver.#17|, next to whom were these here named.Porters - who were to keep the doors of the tabernacle and courts,but with all were instructed in musick, that when these were freefrom attendance upon their proper office, they might not be idle norunprofitable in God's house.