How does one endure a sound not meant for mortal ears to bear?

But how could their mortal ears hear over the deafening song of the chanters.

She sucked in a soft breath too light to be heard by mortal ears.

And the moon made a music at his rising, but it fell a little short of mortal ears.

They came from upwind, moving so quietly that mortal ears would not have heard them.

"So we could exchange confidences without little mortal ears hearing too much," Laurent guessed.

He heard the back door close, though he knew the sound would never reach mortal ears.

Her voice was melodious once more, but the melody was for no mortal ear.

For years, improvements in audio acoustics have produced such tiny differences that few mortal ears can appreciate them.

And then the recorded whisper that mortal ears could not hear: "Traitor!"