Talbiyah in Unison: Permissible?
Question

Is it permissible for one person to recite the Talbiyah after entering ihram and the people who are doing ‘Umrah to repeat it after him, or what?
Praise be to Allah.Reciting the Talbiyah in unison
Reciting the Talbiyah in unison , when the people doing ‘Umrah all start to recite the Talbiyah together and end it together in one voice is one of the mistakes that many people commit today. 
It is not known that the Prophet (peace and blessings of Allah be upon him) or his Companions recited the Talbiyah in unison. Rather each of them should recite the Talbiyah by himself, whether it coincides with the voices of other pilgrims who are reciting the Talbiyah or not. 
The Standing Committee for Issuing Fatwa was asked: What is the ruling on pilgrims reciting the Talbiyah together, where one recites it and the others repeat after him? 
They replied: 
“Reciting the Talbiyah in unison is not permissible. This practice was not narrated from the Prophet (peace and blessings of Allah be upon him) or from his successors, the Rightly Guided Caliphs (may Allah be pleased with them); rather it is an innovation (bid’ah).”
Shaykh Ibn ‘Uthaymin (may Allah have mercy on him) said: 
“The words of Anas (may Allah be pleased with him): “We did Hajj with the Prophet (peace and blessings of Allah be upon him) and some of us were reciting takbir (‘Allahu akbar’) and some of us were reciting tahlil (‘La ilaha ill-Allah’)” (agreed upon) indicate that they did not recite the Talbiyah in unison. If they had been reciting the Talbiyah in unison, then they would all have been reciting tahlil or takbir, but some of them were reciting takbir and some of them were reciting tahlil, but each of them was remembering his Lord according to his situation.” (Al-Sharh al-Mumti’, 7/111) 
And Allah knows best.