A modern equivalent of the same semantic shift would be monitor speakers which are often called 'fold-back' speakers, because they 'fold back' the sound to the musicians on stage, this is almost like an echo, which could be viewed as a "reply" to the person making the noise.

Paulus.

A modern equivalent of the same semantic shift would be monitor speakers which are often called 'fold-back' speakers, because they 'fold back' the sound to the musicians on stage, this is almost like an echo, which could be viewed as a "reply" to the person making the noise.