`  == Analysis  ``actually the wavelength which is affected``. Is this also the case for ``moving observer, stationary source`` ? ==  Regd. Analysis section: Does not explicitly mention which case is analysed - I assumed ``moving source, stationary observer``.  It explains ``So it is actually the wavelength which is affected``. Ok.  However, in the other case, ``moving observer, stationary source``, I was confused by the phrase ``similar analysis``. Analysis may be similar but does the same explanation ``actually the wavelength which is affected`` hold? In this case, doesn't wavelength ``actually`` remain same and relative/perceived sound speed change, thus affecting perceived frequency?`