The Mullah's don't stop at Adhaan, they give khutbahs, naats, Qur'aan recitation all of it on loudspeakers.
If one Mosque in the village used loudspeaker for Adhaan it might be acceptable but they all do it and there's 20-30 mosques in our tiny little village (tribal feuds, nobody wants to pray side by side with their enemies).
That my friend is your actual problem, 20-30 mosques because nobody wants to pray side by side with their enemies explains the whole thing, thank you. As for pain to your granny during daytime then you can provide her earplugs as someone suggested.