When the problems with his impaired hearing became worse, Ludwig van Beethoven tried to find an aid, that would make communication with others easier. So he contacted the well-known mechanic and inventor Johann Nepomuk Mälzel (1772-1838), who had lived in Vienna since 1792, and who had been in close contact with Beethoven around 1812/1813.
Mälzel developed a number of differently shaped ear trumpets for the composer, which partly were to be attached to the head with a metal circlet. (Four of those hearing aids can be seen in the Beethoven-Haus in Bonn, another one is in possession of the society of music-lovers in Vienna.) Apart from the ear trumpets, two other inventions by Mälzel became important for Beethoven. One was the "Panharmonicon", which was some sort of a music box, for which Beethoven wrote the original version of his battle symphony "Wellingtons Sieg" (Wellington's Victory) Op. 91 in 1813. The other invention was the metronome, which he used as the first important composer.(S.B.)