A COMMON MISCONCEPTION ABOUT DOPPLER EFFECT

     Craig Bohren pointed out in 1991 that some physics text books erroneously state that the observed frequency increases as the object approaches an observer and then decreases only as the object passes the observer.  In more cases, the observed frequency of an approaching object declines monotonically from a value above the emitted frequency, though a value equal to the emitted frequency. When the object is closest to the observer and to value increasingly below the emitted frequency as the object recedes from the observer.  Bohren proposed that this common misconception might occur because the intensity of the sound increases as an object approaches an observer and decreases once it passes and recedes from the observer and that this change in intensity is misperceived as a change in frequency.  Higher sound pressure levels make for a small decrease in perceived pitch in low frequency sounds and for a small increase in perceived pitch for high frequency sounds. (Note: This needs additional verifications. Please help to improve this.)