Originally Posted by Pantah
Exactly how does one "shift the resonance point of the bars to some other point of the operating range"?
The guy asked a question and you invent some sort of scientific response for personal effect, yet useless to your audience.
Too many people like you on this site.
To change the resonance point, change either the mass of the bars or their stiffness. The easiest way to reduce the stiffness is to add rubber mounting.
See the section on mass-spring-damper in this article:
Increasing the mass reduces the natural frequency (aka reasonant frequency) however it also reduces the damping factor so you end up increasing the vibrations at the natural frequency.
To make the handlebars smoother, first try to make sure that the natural frequency of the bars isn't the same as the frequency of engine vibrations. Failing that, try to make the damping factor high so you don't get really bad vibrations at that natural frequency.
Explained another way:
you want to be at either the right or the left of these curves. Failing that, you want to be on one of the lower curves rather than a higher one.