The Mishna in Masechet Megilla (17a) says that one who reads the megilla b'serugin u'misnamnem - with pauses and while dozing off, has fulfilled his obligation. The gemara discusses this and while it might not be the best way, you are yotzei your mitzva if it happened.
I have the following question: What is considered a pause that changes your mitzva from l'chatchila to b'dieved? Are the natural pauses and the pauses for the banging of Haman's name, considered pauses or are they part of the megilla? If the banging is a problem that means we are mostly yotzei the mitzva only b'dieved.
I personally feel those pauses for banging are considered l'tzorech of the reading and are not a hefsek rendering the reading b'dieved. However it might be dependant on how long the banging continues and how long the pause is. Maybe shuls needs to be makpid on short pauses of just a few seconds..
I posed the question to a Rabbi last night and he did not have an answer. He is not sure if something that might be considered l'tzorech of the reading changes the status, and he said there are different levels of l'tzorech,so the question would be how l'tzorech is it really.
What do you think?