Question Summary:
Should we reply to an adhān played on a recorder?

Question Detail:

 
Our office is in the basement of a building, where at the time of Zohr salah, a recorded azaan is played to attention every one for Salah time, since we can't hear the azaan called from nearaabout mosques. Can we answer the Azan words or is it necessary to answer Azan only when it is called live from mosque and you are able to hear it.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
An adhān played on a recorder is not considered to be in the ruling of an adhān given by a real person.[1] As such, it is not necessary to reply to such an adhān.[2] If one does so, it is not prohibited either.
And Allah Ta’āla Knows Best
Bilal Mohammad
Student Darul Iftaa
New Jersey, USA 
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net