Vienna horn

During the nineteenth century, a number of experiments were made in adding valves to the natural horn to enable it to play chromatically without the need for hand-stopping.

These experiments included adding piston valves (as used in modern trumpets) to a single F horn.

The horn was still crooked, by inserting other tubing, to re-tune the instrument for music written in base keys other than F. The Vienna horn uses a unique form of double-cylinder valve associated with the Viennese firm Uhlmann of the 1840s known as a pumpenvalve.

When a valve is engaged, each cylinder redirects the air stream 90 degrees in one bend, lessening the resistance felt by the player.

This type of valve is one of the many contributing factors to the liquid legato that is one of the trademarks of the Viennese school.