Aadaab at the time of calling out the azaan:

7. Call out the azaan in a loud voice.

عن عبد الله بن زيد رضي الله عنه قال … فأخبرته بما رأيت فقال إنها لرؤيا حق إن شاء الله فقم مع بلال فألق عليه ما رأيت فليؤذن به فإنه أندى صوتا منك (سنن أبي داود #499)

Hazrat ‘Abdullah bin Zaid (radhiallahu ‘anhu) reports … “I then informed Rasulullah (sallallahu ‘alaihi wasallam) about the dream I had seen (and the manner of calling out the azaan that I was taught in the dream). Rasulullah (sallallahu ‘alaihi wasallam) replied, “Certainly it is a true dream Insha Allah. Stand up with Hazrat Bilaal (radhiyallahu ‘anhu) and tell him the words of azaan you had heard in your dream, so that he may call out the azaan with these words, since his voice is louder than yours.”