129:14 When the person blowing the shofar recites the brachos, the congregation should not respond “Baruch Hu u’baruch shmo” (“Blessed is He and blessed is His Name.”) Rather, one should listen carefully to the brachos, reciting “Amen” after each with concentration. One is forbidden to make any interruptions until after all the shofar notes have been blown during the repetition of the Amidah. Therefore the gabbai may not announce for silence before the Amidah as he might do at other times. (If one did respond “Baruch Hu u’baruch shmo,” it would appear that he fulfills his obligation after the fact – Mishnah Brurah 124:21.)
129:15 The common practice after each sequence of blowing the shofar is to say “Y’hi ratzon…” (“May it be Your will…”) as printed in the Machzor. One should be careful not to say the names of angels written there aloud. In many communities they do not recite “Y’hi ratzon,” which is more correct. (Mishnah Brurah 592:12 says that the “Y’hi ratzon” should be scanned silently but not recited aloud.) The main thing is that the sound of the shofar should arouse within us a sincere desire to repent. As the Rambam wrote (Hilchos Teshuva 3:4), even though blowing shofar on Rosh Hashana is a law of the Torah, it sends a hidden message to us that we should wake up from our slumber. We should examine our deeds and return to G-d. We overlook the truth in foolish activities that are useless and cannot help us. We must improve ourselves and abandon our bad habits.