Reference: I’laam al-Mu’aasireen bi-Fataawa Ibn ‘Uthaymeen – Page 431-432
Question: Is it permissible for a person to listen to an audio recording whilst he is in the toilet and the audio player is outside?
Response: Yes, there is no harm in this; Meaning, it is permissible for a person to place the audio player outside the toilet whilst he listens to it. And it has been related about the grandfather of Shaykh al-Islaam Ibn Taymiyyah, ‘Abdus-Salaam, that he would have his son read to him whilst he (himself) was in the toilet (and his son was outside) in order to benefit from the time.
It may be that this is [considered] to be a valid action, whilst I do not think that a scholar would do this unless he wished to revise an [important] issue from the issues which required further understanding. [Having said this], we say in response to this [matter] that abandoning this [act] is better. Why? Because if a person was to listen to a hadeeth which aroused his intellect, it is quite possible that he may extend his time in the toilet because he is in harmony with what he is listening to and as a result he may end up spending an hour or two [in the toilet]!
We are aware that in the lands of the disbelievers, if a person wants to read a newspaper he would enter the toilet, and you know that their toilets have a seat, so he would sit on the toilet on his thighs with his newspaper with him, and quite possibly he may even have a cigarette [whilst in there]!