Matthew Poole and continuators on 1 Chronicles 15:20

20 And Zechariah , and Aziel, and Shemiramoth, and Jehiel, and Unni, and Eliab, and Maasiah, and Benajah, with Psalteries on Alamoth .

In this Catalogue Ben is omitted, who was mentioned v. 18. Yet others think him to be the same who is called Azariah, v. 21. But Ben might be some other person, who was indeed appointed for this Work as is related, v. 17, 18. and yet he might be taken off by death or sickness, or some sudden and extraordinary Accident which hindred his Execution of the Place and Work allotted for him, which might force the Chief of the Levites to appoint some other in his stead, when they came to put their Institution in practise, as here they did.

Or, with (as that particle is elsewhere used) Alamoth which is thought to be the name of an Instrument of Musick; or of a certain Tune, or Note, or part in Musick. The certain signification of it is not now known, nor is it necessary for us to know it. And the like may be said of Sheminith, v. 21.