John Gill Commentary 2 Chronicles 5:12

"also the Levites who were the singers, all of them, even Asaph, Heman, Jeduthun, and their sons and their brethren, arrayed in fine linen, with cymbals and psalteries and harps, stood at the east end of the altar, and with them a hundred and twenty priests sounding with trumpets;)" — 2 Chronicles 5:12 (ASV)

(See Gill on 2 Chronicles 5:1).