Reference: Sharh ‘Umdatil-Fiqh – Tape No.8, Question No.41
Question: In some of the masjids the adhaan is called using an audio recording; so is this act [something which is] legislated?
Response: No, this is not [to be referred to as] the adhaan; [playing] an audio recording [does] not [take the place of] the mu.adhdhin. The adhaan is an act of worship, and it is imperative that it be carried out by a Muslim; it is imperative that it be carried out by a responsible Muslim. An audio recording is just that, a recording [and nothing more].