Speaking tube

A speaking tube or voicepipe is a device based on two cones connected by an air pipe through which speech can be transmitted over an extended distance.

Dom Gauthey launched a subscription supported by Benjamin Franklin and other French scientists to finance further experiments, but was not able to raise enough money to go ahead.

Early voicepipes consisted of two cones, of wood or metal, one end shaped to fit the speaker's mouth, connected to the other which was flared to amplify the sound (specifically to match the impedance of the tube to that of the open room).

[1] However, very long speaking tubes might use an electrical signalling device to indicate a call, as the large volume of air in the pipe would make it difficult to blow with enough pressure to sound a whistle at the far end.

A voice tube was then used to carry steering orders from the quarterdeck down three decks, to where a gang of sailors operated the ship's tiller directly using ropes and pulleys.

The speaking tube supplemented the array of remotely controlled hand bells that were operated in the upstairs rooms and rang in the servant's quarters in even modest houses in the 19th century.

The phrase "get on the horn" and "give him a blow" as well as the use of "blower" as a synonym for "telephone" are generally accepted as having their origin in this feature of speaking tubes.

Speaking tubes were also used in fine automobiles, such as the 1927 Rolls-Royce Phantom, allowing communication between the separate passenger and driver's compartments when desired.

They are also sometimes used for the microphone on telephonists headsets and to provide music to patients undergoing an MRI scan, as it would be dangerous to use metal wiring in the scanner's magnetic field.