Praise be to Allah.
If this recorded adhaan is broadcast at the time of prayer, it is prescribed to respond to it.
Shaykh Ibn Baaz (may Allaah have mercy on him) was asked: Is it permissible to respond to the adhaan that comes from a radio or TV?
If that is at the time of prayer then it is prescribed to respond to it, because the Prophet (peace and blessings of Allaah be upon him) said: “When you hear the muezzin then say what he says, then send blessings upon me, for whoever sends one blessing upon me, Allaah will send ten blessings upon him in return, then ask Allaah to grant me al-waseelah, which is a position in Paradise that will be granted to only one slave of Allaah, and I hope that I will be the one, then intercession will be granted to him.” Narrated by Muslim in his Saheeh.
And he (peace and blessings of Allaah be upon him) said: “Whoever says when he hears the call to prayer, ‘Allaahummah Rabba haadhihi’l-da’wat il-taammah wa’l-salaat il-qaa’imah, aati Muhammadan al-waseelata wa’l-fadeelah, wab’athhu maqaaman mahmoodan alladhi wa’adtahu (O Allaah, Lord of this perfect Call and the Prayer to be offered, grant Muhammad the privilege and also the eminence, and resurrect him to the praised position that You have promised), will be granted my intercession on the Day of Resurrection.”Narrated by al-Bukhaari in his Saheeh. Al-Bayhaqi added with a hasan isnaad after the words “that You have promised” “innaka laa tukhlif al-mee’aad (You do not break Your promise).” End quote.
Majmoo’ Fataawa Ibn Baaz (10/363).
And Allaah knows best.