Conn Wonder Curved Soprano
Date: 1901. Image Courtesy www.VintageSax.com
In the following I am assuming that Conn's curved soprano's are basically of the same design as the straight soprano's. From what I have been able to infer from various sources on the internet, including this review by Thomas Zinnen of a New Wonder II straight soprano, the Wonder soprano was keyed up to Eb. Additionally, there is a very strong possibility that a modern soprano saxophone mouthpiece won't work properly on this model, causing poor intonation. If you intend to play one of these, you will probably need to find a period mouthpiece. One avenue to explore would be a mouthpiece with a large chamber.