See Poole on "1 Chronicles 15:20". To excel: the word may be here added to note the excellency of that instrument, or note, or part of music; or that there was a greater extension or elevation of the voice than in the former.
Related Commentaries of 1 Chronicles 15:21
1 Chronicles 15:21
21 And Mattithiah, and Elipheleh, and Mikneiah, and Obededom, and Jeiel, and Azaziah, with harps on the Sheminith to excel.