Q. Since we do not fulfill our obligation with a bracha recited over the telephone, why do people answer amen when the sheva brachot under the chupa or at the seuda are said over the microphone? Are the chatan and kalah yotze if they hear the bracha mainly from the loudspeakers?

A. As is mentioned in Talmud (Suka 51b) in regards to the flag signals of the well attended Great Synagogue of Alexandria, we do answer amen even when we did not hear at all the recited brocho, as long as we are aware which brocho is being recited. So rules Igrois Moishe (O.H. 4: 91: 4) in regards to answering amen for a blessing heard via telephone or loudspeaker.

Horav Shlomo Miller’s Shlit”a opinion is that under the chupa, where there is a requirement to be yotze with the first two brochos of the Rov, even when the Rov who performs the ceremony is reciting the brochos using a microphone, since he is so close to the Chosson and Kallah and they could hear him clearly anyway, they comply with his blessings, as they do not need the loudspeakers at all.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a