Appears in Blameless.
A very tall stovepipe-style top hat, with no brim, mounted on a teapot stand with a crank attachment, with a flouted trumpet coming out its underside.
Feed magnetic auditory resonance tape in through a slit in the underside of the hat, turn the crank to run it through the device. A pinging sound emerges, akin to the noise a piano might make after inhaling helium. Crank faster and faster, until the pings began meshing together and eventually a high voice came into existence. Works on the same principle as music boxes only for recording the human voice.