Doppler Cents Puzzler

[robert.scott at tunelab-world.com]

Vladan wrote:

> When we use the Doppler formula with
> frequencies given in Hz, for constant bicycle velocity
> the pitch is sharp by the same number of Hertz when
> approaching as it is flat when retreating from the ice
> cream truck.

Not true.  It is the cents that is constant, not the Hz.

Also consider that the ice cream truck may not have been at perfect pitch to 
start with.  (Although it was certainly very close.)  Actually, I had no 
particular agenda in mind.  I just thought it was interesting that such a small 
velocity could induce such a large (for piano tuners) change in pitch.

Robert Scott
Ypsilanti, MI (currently writing from the lobby of the
Riverside Convention Center in Rochester, NY at the
PTG convention.)