1. Let a sound source produce a single tone at frequency F0. The source is moving on a straight line that passes “through” the observer. Plot the velocity of the source relative to the observer, the signal envelope, and the apparent frequency of the source as functions of time. Generate the sound at the position of the observer.
Summary: When an object passes through an observer (not possible in real life), the velocity remains constant when the object is moving towards the obesever and then becomes negative immediately as it passes through the observer. The shift in frequency is immediate.
Example Shown: Object outputting a 200 Hz sine wave, moving at 20 m/s from position -20 meters to 40 meters.
2. Set up the experiment so that you can specify the minimum distance of the observer from the source trajectory, and repeat (1). Produce a set of results as in part (1) for the listener at some distance away from the source trajectory.
Summary: When the observer stands at a distance when the object passes, there is a gradual shift in frequency as opposed to the immediate change in part 1.
Example Shown: Object outputting a 400 Hz sine wave, moving at 30 m/s from position -20 meters to 20 meters, observer standing 5 meters from object at minimum.
3. Repeat (2) with the source consisting of a composition of a 3-tone signal.
Summary: This simulation is very similar to part 2, but one aspect that is interesting is that each of the frequencies by a different amount as they pass the observer, this is shown in the figure below.
Example Shown: Object outputting 100, 200, and 300 Hz sine waves, moving at 50 m/s from position -100 meters to 100 meters, observer 10 meters from minimum..
4. Assume the receiver is a human listening binaurally. The interaural distance in an adult subject is 17 cm. Repeat the preceding parts for this scenario by ignoring any head shadow effects. Generate the stereo signals appropriate for setups (1) and (2).
Example Shown: Object outputting a 400 Hz sine wave, moving at 30 m/s from position -40 meters to 40 meters.
Code: Project 1 Part 1 in Stereo
Output WAV: Project 1 Part 1 in Stereo
Example Shown: Object outputting a 150 Hz sine wave, moving at 30 m/s from position -100 meters to 100 meters, observer standing 5 meters from object at minimum.
Code: Project 1 Part 2 in Stereo
Output WAV: Project 1 Part 2 in Stereo
Note: The sound increase and decay for each example are linear because the normal 1/R approach led to audio that was not realistic at all and only played a blip of sound.
