Hi stuart , If I may , I would like to ask : Given that one would not switch from Hi Eb to Hi F while playing - why would both tubings would be on the horn at the same time? Maybe there is a way to approacg the whole design as a modular design - an interchangable mouthpipe , tubing, etc . which would be conected in some junction . there is a very interesting story about the veneklassen horn in www.hornplayernet .com . I do not think that all the ideas there are great - the location of a switch valve near the beginning of the leadpipe does not seem to be great . but the Idea of modules... maybe?... Alon _______________________________________________ post: horn@music.memphis.edu unsubscribe or set options at http://music2.memphis.edu/mailman/options/horn/archive%40jab.org