Has anyone ever heard God's voice?
No one has every heard the voice of God. Some have heard God's voice.
Jn.5:37
"Ye have neither heard his voice at any time, nor seen his shape."
Dt.4:12
"And the Lord spake unto you out of the midst of the fire: ye heard the voice of the words, but saw no similitude; only ye heard a voice."
Dt.4:36
"Out of heaven he made thee to hear his voice ... and thou heardest his words."