https://torontodawah.com/ruling-on-beautifying-ones-voice-for-the-athan-shaykh-muqbil-bin-hadi-al-wadii-and-lajnah-permanent-committee-for-scholarly-research-and-ifta/
Ruling On Beautifying One's Voice For The Athan - Shaykh Muqbil bin Hadi al-Wadi'i and Lajnah (Permanent Committee for Scholarly Research and Ifta’)