Q. I daven like many others in a small shul, that is on a main street. It is common that the street noises like trucks going by or sirens are heard inside as well as sometimes small children crying or the A.C. making sounds. Are those noises an issue when hearing the shofar? Do you have to repeat?

A. Remoh (O.H. 588: 3) rules that if two individuals blew the complete set of shofar sounds required on Rosh Hashono at the same time or even if one was blowing a trumpet instead of a shofar, the listener complies with the mitzva. Mishna Berura (ibid. 11) quoting Talmud Rosh Hashana (26a) explains that although usually we accept that two different voices or sounds cannot be heard simultaneously, when one of them is very pleasant and enjoyed as would be the story of Megilas Esther, you would pay attention to the preferred one and thus comply with the mitzva. In the case of the shofar since it comes only once a year it is also appreciated and liked more than any other sound and of course, noise.
However, Horav Shlomo Miller Shlit’a advises to minimize as much as possible any other distressing and conflicting sounds, that may disturb the kavana and intention of the people complying with this great and important mitzva.

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