If I am stationary and a sound source moves towards me at a constant velocity, I will hear it (the sound) increase in frequency until it is adjacent to me and then as it moves away from me, I will hear a decreasing frequency. Fundamental stuff right? It works with radio waves and light which is how we can look for red shifted and blue shifted galaxies and make assumptions about their heading. But, and this is my question... lets say in my example above, the sound source was a car travelling at 50km/h with the driver leaning on his horn for the whole time of observation and that being so, the source of sound is constant in frequency and although moving, the source remains the same as it travels linearly (ie the horn as the car moves towards, then away from me). What if, I set up, say, 100 speakers with a sound frequency generator attached to each (at the same frequency of the car horn as a rather arbitrary decision) and laid them out in a line, say 1 metre apart. Then, using a timer, I have them emit their sound (all emitting the exact same frequency), starting at one end and at such intervals as to simulate a vehicle moving at 50km/h. If I were to then stand in the middle of this line of speakers, would I hear the Doppler effect as the sound "approaches" me, then "moves away" from me? I had a reasonable argument in class about this today and would like some outside input.