Althorn (Alto horn) brass wind musical instrument

Alto Horn (Tenor Horn) is a brass, wide-bore conical wind instrument from the saxhorn family. The standard key of the alto horn is E-flat (Eb). The nominal range of the alto horn extends from A below the bass clef to Eb above the treble clef; experienced players can reach at least a third higher.

The Alto Horn is called by different names in various countries. In the United States, it is known as the Alto Horn, whereas in the United Kingdom, it is called the Tenor Horn. The German name is Althorn. In France, it may be referred to as Saxhorn or Picotte, and in Italy, the name Genis is used.

The first alto horn was designed by the Belgian maker Adolphe Sax and patented in 1840. Sax patented two similar instruments, named the saxhorn and the saxtromba. The alto instrument features bore diameters described in the saxtromba patent. In this patent, the soprano voice is set in Eb, descending through Bb (contralto) to Eb (alto). The next lower instrument was described as a Bb baritone, although logically it should have been a tenor. Inconsistencies in descriptions and Sax’s vigorous patent defenses led to lasting confusion regarding the nomenclature of tenor and alto horns. Modern alto horns feature a larger bore, closer to the saxhorn specification.

The alto horn has a predominantly conical leadpipe, similar to the euphonium or flugelhorn. A deep, cup-shaped mouthpiece is used. This combination produces a mellow, rounded tone used as a middle voice, supporting trumpets, cornets, and flugelhorns, while bridging the gap above lower tenor and bass instruments like the trombone, baritone, and tuba.

Modern alto horns come in various shapes. The most common resemble a small tuba with an upright bell. In Europe, a solo form resembling a large flugelhorn with a front-facing bell is frequently used. There is also a "backward-facing" bell variant used in marching bands.

The Czech company Cerveny has been producing alto horns with rotary valves since 1852, including oval models. Significant innovations have been made by Besson and Yamaha. Today’s flagships include the Besson Sovereign and Yamaha Maestro.