[Machine] Umar used to perform the takbir (saying "Allahu Akbar") loudly in his tent in Mina. The people in the mosque would hear him and also perform the takbir, and then the people in the market would hear and also perform the takbir. This would continue until Mina would echo with one unified takbir. It is also mentioned about Ibn Umar that he used to perform the takbir in Mina during those days, after prayers, on his bed, in his cloak, and in all places he would go during those days.  

عَنْ عُمَرَ ؓ كَانَ يُكَبِّرُ فِي قُبَّتِهِ بِمِنًى فَيَسْمَعُهُ أَهْلُ الْمَسْجِدِ فَيُكَبِّرُونَ فَيَسْمَعُهُ أَهْلُ السُّوقِ فَيُكَبِّرُونَ حَتَّى تَرْتَجَّ مِنًى تَكْبِيرًا وَاحِدًا وَيُذْكَرُ عَنِ ابْنِ عُمَرَ أَنَّهُ كَانَ يُكَبِّرُ بِمِنًى تِلْكَ الْأَيَّامَ وَخَلْفَ الصَّلَوَاتِ وَعَلَى فِرَاشِهِ وَفِي فُسْطَاطِهِ وَمَجْلِسِهِ وَمَمْشَاهُ تِلْكَ الْأَيَّامَ جَمِيعًا