The rear wall of the bureau is, like the others, designed in the form of an architectural facade. The lower central panel of the door is covered with cloth so that the music can be heard better. The musical mechanism operates automatically when the little cabinet comes up. The door opens at the same time. The mechanism incorporates and organ with 19 wooden pipes and a stringed instrument known as a psaltery. A single brass cylinder carries "recordings" of four melodies. The "track" can be changed using a lever located to the left beneath the desk top. This musical mechanism, like others in Roentgen's furniture, was created by the master clock-maker Peter Kinzing.