Our Shaykh mentioned from ash-Shaatibee (in al-Iıtisaam), and those that quote from them that the prophetic adhaan was called from the minaarah (minaret). Likewise, it was quoted similarly from Ibnul-Haaj, (in al-madkhal). However, he (Shaykh al-Albaanee - rahimahullaah) was not pleased with that statement, and he said (in al-Ajwibah an-Naafiıah page 33-35) under the title: Was there a minaret in the time of the Prophet (sallallaahu ıalayhi wa sallam)?
al-Albaanee commented, I did not come across that which clearly shows that the prophetic adhaan was on the minaret, except that which preceded in the hadeeth that it was above the entrance of the masjid. So from what is apparent, is that it (the adhaan) was called upon the roof, above the entrance. And what supports this claim from that which is well-known is that Bilaal, the one who would call the prophetic adhaan on the day of Jumu'ah, had something to climb upon in order to call the adhaan.
In the Saheeh of Imaam al-Bukhaaree, al-Qaasim Ibn Muhammad narrated from 'Aa'ishah that Bilaal would call the adhaan in the night, so the Messenger of Allah (sallallaahu ıalayhi wa sallam) said, "Eat and drink until Ibn Umm Maktoob calls the adhaan, surely he does not call the adhaan until the time for fajr enters." al-Qaasim said, ıThere wasnıt between their adhaans except that one was rising and the other was descendingı
Then our Shaykh said in the previous book, "In summary, that which I hold in this topic is that it has not been established that the minaret was known to be part of the masjid at the time of the Prophet (sallallaahu ıalayhi wa sallam). In conclusion, the adhaan in that time was made from a raised place above the masjid, climbed upon, as mentioned previously. From that which is likely is that the climbing that was mentioned was only at the back of the masjid, and it is also likely that it was upon something that was (raised) above the back of the masjid. As comes in the hadeeth of Umm Zayd, in either two situations, that which we take to be correct, is that the minaret which is known today is not from the Sunnah in any way, however, that which is the intended meaning of it, a conveyance (call to prayer) is a legislated affair without doubt. If the conveyance (call to prayer) cannot take place except by it, then at this point, it is legislated, as is found in Usoolul-'Ilm:
If that which is waajib cannot take place without it, then it, itself, becomes obligatory, to the extent of whatıs needed.
However, my opinion is that the presence of microphones or (other) conveyance tools of today frees us from the (need for) minarets, especially since it (the minaret) is expensive (and burdensome). Its construction under these circumstances, considering it is an innovation, and having that which frees us from needing it, is not legislated. Because whatıs found in it of extravagance and wasting money, and that which shows with irrefutable proofs, that it has become something of no benefit. Verily, the muıadhineen (callers of the adhaan), never ascend it and are not in need of it because of the amplifiers.
Footnotes:  Al-Bukhaaree (4/110)  al-Ajwibah an-Naafi'ah page 33-35