In 1911, Wurlitzer became the top supplier of automatic harps to brothels in the Barbary Coast, San Francisco's red-light district. 

But first, what is an automatic harp? Why would anyone, let alone a brothel, want one?

In the late 1890s, Wurlitzer released the Tonophone, a coin-operated player piano that it marketed to restaurants. The Tonophone was so successful that Wurlitzer followed it with other, increasingly elaborate automatic instruments.

Coin-operated, pneumatic, and capable of a ten-song playlist, the Tonophone was released by Wurlitzer in 1897. At the heart of the Tonophone was a cylinder that ran the width of the piano. This cylinder was covered in raised metal pins that sort of resemble staples of varying lengths. 

As the song played, the cylinder continuously rotated, and as it did, the pins would lift levers: one lever for each note. In turn, the levers opened valves that pneumatically operated the keys.