Related Clues:

• Bat's navigation aid
• It may bounce off walls
• Bounce back
• Unoriginal reply
• Resounding response
• It may be off the wall
• Sonar comeback
• Off-the-wall comeback?
• Recording studio effect
• Output of 31-Down
• It comes back to a spelunker
• Yodeler's reverberation
• Second coming?
• Off-the-wall reply
• Sound rebound