So the singers, Heman, Asaph, and Ethan,.... The three principal of them: these were appointed

to sound with cymbals of brass; for as there were three sorts of musical instruments, 1 Chronicles 15:16 these three chief singers had one of those instruments appropriated to them, one of which were the cymbals of brass, to which the apostle alludes, 1 Corinthians 13:1.

These singers formed three choirs, according to the instruments they played. Heman, Asaph, and Ethan played brazen cymbals להשׁמיע (1 Chronicles 15:19); Benaiah and the seven who follow played nablia (psalteria) עלמות על (1 Chronicles 15:20); while the last six played lutes (harps) לנצּח השּׁמינית על (1 Chronicles 15:21). These three Hebrew words plainly denote different keys in singing, but are, owing to our small acquaintance with the music of the Hebrews, obscure, and cannot be interpreted with certainty. נצּח, going over from the fundamental signification glitter, shine, into the idea of outshining and superior capacity, overwhelming ability, might also, as a musical term, denote the conducting of the playing and singing as well as the leading of them. The signification to direct is here, however, excluded by the context, for the conductors were without doubt the three chief musicians or bandmasters (Capellenmeister), Heman, Asaph, and Ethan, with the cymbals, not the psaltery and lute players belonging to the second rank. The conducting must therefore be expressed by להשׁמיע, and this word must mean "in order to give a clear tone," i.e., to regulate the tune and the tone of the singing, while לנצּח signifies "to take the lead in playing;" cf. Del. on Psalm 4:1. This word, moreover, is probably not to be restricted to the singers with the lutes, the third choir, but must be held to refer also to the second choir. The meaning then will be, that Heman, Asaph, and Ethan had cymbals to direct the song, while the other singers had partly psalteries, partly lutes, in order to play the accompaniment to the singing. The song of these two choirs is moreover distinguished and defined by עלמות על and השּׁמינית על. These words specify the kind of voices; עלמות על after the manner of virgins, i.e., in the soprano; השּׁמינית על, after the octave, i.e., in bass - al ottava bassa. See Del. on Psalm 6:1; Psalm 46:1. In 1 Chronicles 15:22-24 the still remaining priests who were engaged in the solemn procession are enumerated.

So the singers, Heman, Asaph, and Ethan, were appointed to sound with cymbals of brass;

15:1-24 Wise and good men may be guilty of oversights, which they will correct, as soon as they are aware of them. David does not try to justify what had been done amiss, nor to lay the blame on others; but he owns himself guilty, with others, of not seeking God in due order