Actually No... Here's a Flash simulation for Doppler effect which I found useful while googling. It really does exist and not some random appearance..! So, The term Apparent frequency is good to use.

We know that Sound is a form of mechanical vibration. When the source moves away from the stable observer at some noticeable speeds (relative to observer) or the observer moves away from the stable source, the frequency of sound perceived by the observer is always less than the actual frequency of the source. It could be easily imagined when you stand somewhere along the roadside and a speeding car passes by... (which is provided in Scene 1 of the simulation). For the reversal (i.e. either the observer or the source moving towards each other), it happens exactly antonymous...

One thing to notice in Doppler effect is that when the observer speeds at the speed of sound relative to the source, his detector (ear) doesn't oscillate at all. I mean, you'd probably hear Nothing...

Actually No. Here's a Flash simulation for Doppler effect which I found useful while googling. It really does exist and not some random appearance..! I don't know whether the term Apparent frequency is good to use or not...

We know that Sound is a form of mechanical vibration. When the source moves away from the stable observer at some noticeable speeds (relative to observer) or the observer moves away from the stable source, the frequency of sound perceived by the observer is always less than the actual frequency of the source. It could be easily imagined when you stand somewhere along the roadside and a speeding car passes by... (which is provided in Scene 1 of the simulation). For the reversal (i.e. either the observer or the source moving towards each other), it happens exactly antonymous...

One thing to notice in Doppler effect is that when the observer speeds at the speed of sound relative to the source, his detector (ear) doesn't oscillate at all. I mean, you'd probably hear Nothing...

Actually No... Here's a simulation for Doppler effect which I found useful while googling. It really does exist and not some random appearance..! We know that Sound is a form of mechanical vibration. When the source moves away from the stable observer at some noticeable speeds or the observer moves away from the stable source, the frequency of sound perceived by the observer is always less than the actual frequency of the source. It could be easily imagined when you stand somewhere along the roadside and a speeding car passes by... (which is provided in Scene 1 of the simulation). For the reversal (i.e. either the observer or the source moving towards the other), it happens exactly antonymous...

One thing to notice in Doppler effect is that when the observer speeds at the speed of sound, his detector (ear) doesn't oscillate at all. I mean, you'd probably hear Nothing...

Actually No... Here's a Flash simulation for Doppler effect which I found useful while googling. It really does exist and not some random appearance..! So, The term Apparent frequency is good to use.

We know that Sound is a form of mechanical vibration. When the source moves away from the stable observer at some noticeable speeds (relative to observer) or the observer moves away from the stable source, the frequency of sound perceived by the observer is always less than the actual frequency of the source. It could be easily imagined when you stand somewhere along the roadside and a speeding car passes by... (which is provided in Scene 1 of the simulation). For the reversal (i.e. either the observer or the source moving towards each other), it happens exactly antonymous...

One thing to notice in Doppler effect is that when the observer speeds at the speed of sound relative to the source, his detector (ear) doesn't oscillate at all. I mean, you'd probably hear Nothing...