How did Beethoven compose music he could barely hear?

Beethoven composed while losing his hearing because the music lived in his head first. He had heard and played music for about thirty years before his deafness set in, so he knew exactly how a violin, a horn or a choir would sound, and how they would sound together. His hearing faded slowly rather than all at once, which let him keep imagining his compositions in full detail. Writing music was, for him, closer to writing down what he already heard inside than to trying things out on the piano.

It was still a brutal struggle. His hearing began to fail around 1798, with a severe ringing in his ears. In 1802 he wrote a letter to his brothers, never sent, admitting he had thought of suicide, but resolving to live for his art. Later, friends had to write their side of conversations in notebooks.

He also found physical tricks. His housekeepers remembered him holding a pencil in his teeth, its other end touching the piano, to feel the notes vibrate. And contrary to legend, he never went completely deaf: he could still make out low tones and sudden loud sounds.

At the premiere of his Ninth Symphony in 1824, he stood beside the conductor, several bars behind, until a young singer turned him around to see the audience cheering.