Well, it seems there is only one mention in the Bible of the Lord blowing a trumpet and that’s in Zachariah 9...
13 When I have bent Judah for me, filled the bow with Ephraim, and raised up thy sons, O Zion, against thy sons, O Greece, and made thee as the sword of a mighty man.
14 And the Lord shall be seen over them, and his arrow shall go forth as the lightning:
and the Lord God shall blow the trumpet, and shall go with whirlwinds of the south.
15 The Lord of hosts shall defend them; and they shall devour, and subdue with sling stones; and they shall drink, and make a noise as through wine; and they shall be filled like bowls, and as the corners of the altar.
16 And the Lord their God shall save them in that day as the flock of his people: for they shall be as the stones of a crown, lifted up as an ensign upon his land.
17 For how great is his goodness, and how great is his beauty! corn shall make the young men cheerful, and new wine the maids.
The implications of this passage are examined here:-