Possible Clues:

• A high range perceptible to the ear
• It's not 17 down, in a manner of speaking
• For listeners only
• Sensory, in a way
• Sonic
• By ear though sounds by mouth
• Like some physical tests
• Not the sound of speaking, it's for hearing
• You can hear this if it's spoken, by the sound of it
• Relating to the hearing organs