An apparatus for automatically recording sound vibrations, incorporating a membrane which vibrates in response to sound waves and has a point…

Any of various devices by means of which sound vibrations are converted into a visible form, graphical or electronic record, etc.

something that marks or indicates the passage of time; an automatic device for doing this.

= phonautograph, n. Obsolete. rare.

An instrument for observing the vibrations of a thin film of soap solution in response to sound waves.

An instrument for tracing curves representing sonorous vibrations.

a device whereby acoustic vibrations are rendered visible.

An instrument for measuring or recording mechanical vibrations.