MAKKAH — About 7,500 speakers spread throughout the Grand Mosque, its floors, squares, corridors, and streets surrounding the Grand Mosque, transmit the sound of the call to prayer and the imam as part of an advanced sound system. The Director of the General Administration for Operation and Maintenance of the General Presidency for the Affairs of the Grand Mosque and the Prophet’s Mosque, Mohsen Al-Salami, explained that the sound system in the Grand Mosque is one of the largest sound systems used in the world, as it functions through an advanced acoustic sensor with the sensitivity that commensurates with the need of the place. He affirmed that the sound is transmitted through modern devices that are operated by highly-trained specialists, so the sound signal is transmitted to the recipients in complete clarity. Al-Sulami emphasized that the sound system of the Grand Mosque operates under a strict and supervised efficiency to avoid breakdowns, by having a basic backup and emergency system due to the sensitivity of the sound in the Grand Mosque. In the event of a malfunction in the main system, he disclosed that the operations will instantly and automatically transfer to the backup system according to the established order until the main system is repaired, adding that the entire audio system is connected to high-capacity UPS devices to ensure that the electrical equipment is not cut off for all audio locations. Al-Sulami said more than 65 specialized operational staff of engineers, technicians, supervisors, and operators looking after these functions to ensure a precise implementation in accordance with relevant technical instructions and to ensure that they are free from any defects by using the latest technology, adding that the audio systems are being operated from the main control room of the second or sub-Saudi expansion in Al-Masaa area. He also said that the team communicates with each other through the "Intercom" to ensure that the sound is not interrupted ahead of any ritual, and well before the call for prayer to ensure the integrity of the system.