In the late period of the baroque trumpet, the desire arose for a chromatically playable trumpet in a lower pitch. There have been various attempts, such as the soprano trombone, the English slide trumpet and attempts with holes and keys added to the baroque trumpet. The invention of Anton Weidinger (1766-1852) to add a system of several tone holes to a natural trumpet (approx. 1800) made it possible to play melodies in the lower range.
The Haydn- and the Hummel Concerto has been composed to this type of instrument. THEIN developed the Key Trumpet further in terms of intonation, an even response and optimized it with 7 keys, a water key, sliding tuning slide with ring for fine intonation as well as with plug-in bows in Eb and E.
Key: Eb (430 Hz), or 440 Hz