In the event that the muezzin's voice is distant and unclear, is it permissible for me to repeat the call to prayer on my own?

Following the muezzin is a Sunnah for the listener, according to the Prophet, peace and blessings be upon him, who said: "When you hear the call (to prayer), say as the muezzin says." Following is not prevented if the voice is distant or unclear, and the listener will be rewarded for their effort.