A:
It is a Sunnah
to raise the voice with Adhan even if it is done by loudspeakers or heard by not Tahir people.It is a Sunnah (whatever is reported from the Prophet) for a person who hears Adhan to respond to it and repeat after the Mu'adhin (a caller for Prayer) except in Al-Hay`alah (Saying Hay `Ala Al-Salah, Hay `Ala Al-Falah [come to Prayer, come to success]), he should say: "La Hawla Wala Quwwata Illa Billah" (There is neither might nor power except with Allah) even if he is not Tahir. This is a kind of general Dhikr (Remembrance of Allah), which does not require purification because purification is meant for Salah, circumambulation, and reciting the Qur'an from the Mus-haf (copy of the Qur'an).May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.