Is Adhan Necessary for Prayer?
Question

Is the giving of the adhan a necessity? We, college students, do not have a mosque near our dorm and so we pray in a musalla. Now, do we have to give the adhan before the prayer, we do hear the sound coming from distant mosques.
Praise be to Allah.What is adhan?
Adhan in Arabic means proclaiming or announcing. Allah says (interpretation of the meaning): 
“And proclaim [adhdhin] to mankind the Hajj (pilgrimage).” [al-Hajj 22:27]
In Shari’ah terminology, adhan means: worshipping Allah by announcing the time of the obligatory prayer, using phrases that have been narrated from the Prophet (peace and blessings of Allah be upon him), in a specific manner. 
Is adhan necessary?
The fuqaha are agreed that the adhan is one of the unique features and manifest symbols of Islam, but they differ as to the rulings on it. 
Some say that adhan is fard kifayah (a communal obligation); this is the view of Imam Ahmad and was the view favoured by Shaykh al-Islam Ibn Taymiyah; among contemporary scholars it is the view of Shaykh Ibn ‘Uthaymin (may Allah have mercy on him). 
And some said that adhan is a Sunnah mu’akkadah. 
The correct view is that adhan is fard kifayah; if someone who is competent does it, the rest are absolved of sin.
Hadith about adhan
The evidence for that comes from the Sunnah.  
Malik ibn al-Huwayrith said: we came to the Messenger of Allah (peace and blessings of Allah be upon him) when we were young men close in age, and we stayed with him for twenty days. The Messenger of Allah (peace and blessings of Allah be upon him) was merciful and kind; he thought that we were missing our families so he asked us about our families whom we had left behind, then he said, “Go back to your families, and stay with them; teach them and instruct them. When the time for prayer comes, let one of you give the call to prayer and let the oldest of you lead you in prayer.” (Narrated by al-Bukhari, 602; Muslim, 674). 
According to a report narrated by al-Bukhari, 604: “When you both go out, give the call to prayer (adhan), then the call immediately before the prayer (iqamah), then let the older of you lead you in prayer.” 
According to a report narrated by al-Tirmidhi (205) and al-Nasai (634): It was narrated that Malik ibn al-Huwayrith said: I came to the Messenger of Allah (peace and blessings of Allah be upon him) with a cousin of mine, and he said, “When you travel, give the call to prayer (adhan), then the call immediately before the prayer (iqamah), then let the older of you lead you in prayer.” (Classed as sahih by al-Albani in Irwa al-Ghalil, 1/230). 
This hadith indicates that the adhan is a communal obligation, because the Prophet (peace and blessings of Allah be upon him) enjoined that only one person should give the call to prayer for a group; he did not tell the whole group to give the call to prayer. See Tawdih al-Ahkam, 1/424. 
Al-Nawawi said: 
“This indicates that giving the call to prayer and praying in congregation are prescribed for travelers. It also shows that it is always encouraged to give the call to prayer, whether one is travelling or not.” (Sharh Muslim, 5/175)
Is prayer valid without adhan and iqamah?
The scholars of the Standing Committee said: 
“The adhan is fard kifayah (a communal obligation) in a town, and the same applies to the iqamah. If a person starts to pray without the adhan or iqamah , whether out of forgetfulness or ignorance, or for some other reason, the prayer is still valid.” (Fatawa al-Lajnah al-Daimah, 6/54) 
Shaykh Ibn ‘Uthaymin said: 
“The evidence for them – i.e., the adhan and iqamah – being obligatory is the command of the Prophet (peace and blessings of Allah be upon him) in a number of ahadith, and the fact that he always did that whether he was travelling or not, and because the time of prayer cannot usually be known without it, and because it serves a purpose and because it is one of the manifest symbols of Islam.” (Al-Sharh al-Mumti’, 2/38)
Based on the fact that the adhan is fard kifayah, if the adhan is given in a town and the people can hear it, then the communal obligation has been discharged and there is no need to give the adhan for every congregation. But it is better and preferable to give the adhan even if a person is praying alone. 
Is it obligatory to give the adhan in every mosque?
The Standing Committee was asked: 
Is it obligatory to give the adhan over loudspeakers in every mosque in every neighbourhood, knowing that the adhan from one mosque can be heard by all the Muslims? Or is the adhan from one mosque sufficient for all the mosques of the neighbourhood? 
The answer was: 
“The adhan is fard kifayah, so if a muadhdhin gives the adhan in one neighbourhood and all the residents can hear it, that is sufficient. But it is prescribed for the people of each mosque to give the adhan because of the general meaning of the evidence.” 
Based on this, it is preferable for you to give the adhan, although that is not obligatory for you. 
And Allah knows best.