Related for Taanit 2:15

On fast days they blow three sets of three each, and when breaking camp they blow three sets of three each, three for each standard. [These are] words of R. Yehuda; but the [other] sages say: Three by every tribe. What are they blowing with? [Answer:] With the trumpets that Moses made. R. Yehuda says: In the New Year one blows on [horns] of rams and in the year of jubilee on [horns] of Capricorns; scholars have placed the common with the common and the uncommon with the uncommon.