Revelation 8:6

So the seven angels who had the seven trumpets prepared themselves to sound.

·        Sound is associated with the seal judgments. The first four are released by a voice like thunder.  The fifth seal describes the intercessory cry from beneath the altar. In the sixth seal, the kings cry out. Here, the terrifying silence of the seventh seal is in great contrast with the other six seals.

·        We waited for the seven seals to be opened, and saw them loosed one by one. But when the seventh seal was finally loosed, the end did not immediately come. It set in motion seven trumpets that would sound upon the earth. (DG)

 Leviticus 23:24 Speak to the children of Israel, saying:  in the seventh month, on the first day of the month, you shall have a Sabbath-rest, a memorial of blowing of trumpets, a holy convocation.

Joshua 6:4 And seven priests shall bear seven trumpets of rams’ horns before the ark.  But the seventh day you shall march around the city seven times, and the priests shall blow the trumpets.