I think something just blew my mind, but I need you knowledgable lot to help me understand what I just saw.
I was watching this educational film from AT&T (Bell Labs) on wave patterns from 1959.
At 19:11 Dr. J.N. Shive talks about how wave energy gets reflected when it encounters abrupt impedance differences, and at 22:02 he explains how this reflection can be minimized with a gradual change in impedance.
How is this relevant for bicycles?
All butted tubing I've seen has had gradual butts, where the wall gradually thickens into the butt. I think that if one were to have abrupt butting with no sloping, there would be much more resonating energy going back and forth in the tube under use. This would mean that "perfect" butting would be totally smooth, with as gradual thickening as possible instead of going thin-slope-thick.
In the video, the "fat" part of the wave machine would represent the butt in the frame tube, the "impedance matching device" would be the slope and the thin part would be the tube where the wall is at its thinnest.
I think sleeves or center bulges in handlebars serve the same function - avoiding sudden impedance change between the bar and the larger diameter of the stem clamp.
What do you think? Am I off my rocker or am I on to something?