The Prophet (peace and blessings be upon him) said:
"The mu'adhdhin is forgiven as far as his voice reaches, and his reward is equal to the reward of those who pray with him."
Hadith Referenceصحیح الجامع الصغیر / حرف الميم / 6643
Hadith Gradingالألبانی:صحيح
Hadith Takhrij[طب] عن أبي أمامة. صحيح الترغيب ٢٣١.