Dear Rumi and all, AA
I promised to write the interesting history of the use of loudspeakers for Azaan.
It was 1941 when Mufti Muhammad Shafi of Deoband, later the Mufti Azam of Pakistan, was asked a question. The microphones and loudspeakers were new to India at that time. The question was whether the use of microphones/loudspeakers was Halal (Permissible) for Azaan or not. The Mufti Sahib humbly said that he needed to investigate before answering the question.
What was his investigation? He invited a Hindu science-master from a school and asked him if the sound from the loudspeaker was naturally a man's voice or not. The science-master was honest and realized his limitations. He said that he did not know much about the electrical activity, but listening to the sound, it appeared to him that the sound through the loudspeaker was not a man's natural voice.
Well, Mufti Shafi Sahib had no hesitation in issuing the FATWA that Azann through the system was absolutely Haram. That Fatwa still hangs in Deoband, India but the Dar-ul-Uloom and Masjid of Mufti Sahib Marhoom in Pakistan has six microphones and ten loudspeakers since 1947 when he was very much alive :-)
I think, the instruments must be banned throughout the Muslim World (and elsewhere) since they are a great distraction and blatant violators of human rights.