Albert Barnes Commentary Numbers 10:2

"Make thee two trumpets of silver; of beaten work shalt thou make them: and thou shalt use them for the calling of the congregation, and for the journeying of the camps." — Numbers 10:2 (ASV)

The trumpet was a straight instrument, differing in this respect from the curved horn or cornet; and is represented among the other spoils of the temple on the Arch of Titus. See (Exodus 25:23). From Egyptian monuments it appears that the Jewish trumpet was copied from that used in the armies of the Pharaohs. The cornet was at first a simple ram’s horn (Joshua 6:4), and the metal instrument of later times preserved the original shape.