Ruling of modulating and elongating vowels in the Athaan
14-1-2014 | IslamWeb
Question:
Is it permissible to elongate the vowels excessively in the Athaan like the way of ‘Abdul Baasit ‘Abdus-Samad? Thanks.
Answer:
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
According to the majority of scholars, it is Makrooh (i.e. disliked) to elongate the vowels excessively in the Athaan. The Athaan will not be invalid as long as the meaning is not changed. However, if the meaning is changed or manipulated, this will be prohibited. This opinion was adopted by Maaliki, Shaafi‘i, and Hanbali scholars of jurisprudence.
Accordingly, the Mu‘athin is not to elongate the vowels excessively in the Athaan because ‘Umar ibn ‘Abdel Azeez 
said: “Call a good Athaan or keep away from us.” [Al-Bukhari]
Ibn Hajar 
said in Fat-h Al-Baari: “Apparently, he feared that if the vowels would be elongated excessively in the Athaan it would go beyond Khushoo‘ (i.e. submissiveness), and was not forbidding him to raise his voice.”