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10. Must one hear all the sounds from the same blower?
One is not required to hear all the blows from the same person. Hence even if one heard a Tekiah from one person and a Teruah from another and a Tekiah from another it is valid. This applies even if every sound was sounded by a different blower. See Chapter 10 Halacha 16!
 590:14; see also 585:8-9; R”H 34b