Waves & Optics / waves / propagation
The Medium Sets the Wave Speed
The misconception
That a louder sound or a bigger pulse travels faster, and that turning up the frequency speeds the wave along. Amplitude and frequency are set by the source; speed is set by the medium, and v = fλ trades wavelength for frequency at fixed v.
How fast a wave travels is a property of the medium — tension and density for a string, stiffness and density for air. Shaking harder makes the wave bigger, shaking faster makes it shorter; neither makes it faster.
Nothing published references it yet, so it sits low in the queue.