Why do there is a loudspeaker on a mosque
Did any moulavi or imam discover a loudspeaker
How they managed before the discovery of loudspeaker

Hi Mandalay,

http://www.saudiaramcoworld.com/issue/200202/the.minaret-symbol.of.faith.power.htm

Once, a muezzin could rely on the strength of his lungs to lift the call to prayer above the clamor of a traditional city's activities, but today's muezzin cannot be heard without amplification above the modern city's incessant traffic and industrial noise. And outside the Muslim world, municipal noise restrictions often limit the volume at which Muslims can call the faithful to prayer, thus obviating the need for a muezzin's tower—and giving rise to imaginative substitutes
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Hope this helps.

I often go on holiday to Turkey and being a muslim country there is Mosques all over and you can here the loud speaker calling to prayer.
I do not know why they have it but I suppose it is saving someone's voice