What is an auxetophone?

Answer 1

An auxetophone is a form of pneumatic sound-playback device used in the early part of the 20th century.

Answer 2

An auxetophone is a device that allows for the amplification of sound, usually through the use of mechanical amplification techniques. It was developed in the early 20th century as a way to increase the volume of sound produced by orchestras and other musical performances without the need for electronic amplification.