Ruling on installing additions to loudspeakers in Mosques
Question

                In recent years it has become common to install additions to loudspeakers in mosques which increase the volume and make the sound echo in all corners of the mosque. What is the ruling on installing this equipment?.
Praise be to Allah.
    If the installation of this equipment does nothing more than 
    improve the sound inside the mosque, there is nothing wrong with it, but if 
    it makes the sound of the letters reverberate then it is haraam, because it 
    means that it is adding a letter or two to the recitation, and changing the  
    words of Allaah to something other than that which was revealed. It says in
    al-Iqnaa’: Ahmad regarded it as makrooh to recite in a wavering 
    choice and he said: it is an innovation. If it also results in changing the 
    pronunciation of the Qur’aan and making the vowels sound like letters, then 
    it is haraam. End quote. 

    But if the sound comes out of the mosque from the top of the 
    minaret and there are no other mosques around whose worshippers may be 
    disturbed, or dwellings whose people will be disturbed by the sound, then I 
    hope that there is nothing wrong with that. But if there are other mosques 
    around whose worshippers will be disturbed or dwellings whose  people will 
    be disturbed by the sound, then it should not be done from the top of the 
    minaret, because that is annoying and disturbing others. It was narrated 
    that Abu Sa’eed a-Khudri (may Allaah be pleased with him) said: The 
    Messenger of Allaah  (peace and blessings of Allaah be upon him) 
    observed i'tikaaf in the mosque and he heard them reciting Qur’aan out loud. 
    He drew aside the curtain and said: “Each one of you is conversing privately 
    with his Lord, so do not disturb one another and do not raise your voices 
    above one another in reading Qur’aan, or in prayer.” Narrated by Abu Dawood. 
    A similar report was narrated by al-Bayaadi Farwah ibn ‘Amr, as was narrated 
    by Maalik in al-Muwatta’. Ibn ‘Abd al-Barr said: The hadeeths of 
    al-Bayaadi and Abu Sa’eed are saheeh. Shaykh al-Islam Ibn Taymiyah said: No 
    one should recite Qur’aan so loudly that he annoys others such as those who 
    are praying. End quote. 
Majmoo’ Fataawa Ibn ‘Uthaymeen, 
    15/160.