Part of the celebration of Purim is the reading of the Book of Esther twice during the 14th of Adar. The first time at night (next Saturday night, February 23rd ) and the second time during the day (Sunday, February 24th).
The reading should be done from a Megila, a scroll or igeret. This igeret was meant to be an official document, to be registered in the royal Archives of the Persian Empire. Rabbi Abraham Eben Ezra explains that this is the reason why Mordekhay did not write the name of God in Megilat Esther. He knew that, following the protocols of those days, when the Persian officers would translate the story of Purim to the Persian language, they would have changed the name of HaShem to the name of one of their gods.
Because the Megila is an igeret (as oppose to a book) the custom is to unroll the Megila as an open document and read from it. At the end, we first roll it and then we say the final blessing. (MT, Megila 2:11).
When the ba'al qore (reader) reads the Megila everybody should listen and follow his reading silently from a scroll or from a printed Megila.
Because it is an igeret, if the reader makes a mistake at the reading, we do not need to correct him (en medaqdeqim beqri-atah MT, Megila 2:7). The general custom is that the somekh (the reader's assistant) would correct the reader only if the mistake he made affects the meaning of the word.
There is no Halakhic objection to use a microphone when reading the Megila in public, provided it could be heard without the microphone as well. Listening by media (TV, radio, phone) is not acceptable for fulfilling the Miṣva of Megila.
Shabbat Shalom!
Candle-lighting in NYC: 5:12 pm
Shabbat ends in NYC: 6:10 pm
WATCH
The story of Asael Lubotzky