"Cone effect" creates waves that do not follow Huygens' principle

[matthew-blackman]

The sound sim applies a "cone" effect for the sound waves, which looks like this:

The physics displayed here are problematic both in terms of accuracy as well as pedagogy. The correct behavior is displayed in the 'Waves Intro' and 'Wave Interference' sims:

I strongly recommend removing this cone effect, as it is not an accurate model can be confusing to students (eg. Why am I able to hear sound from a speaker if I'm standing next to it and not in front of it?)

[matthew-blackman]

The code that creates this cone is in a function called applyTemporalMask in SoundModel.ts. Removing the call to this function causes the first screen of the sim to look like the following:

This is a huge improvement in my opinion. It more accurately shows how sound waves emanate from a speaker, while obeying Huygens' principle and justifying why you can hear the sound anywhere in the room (even without reflections).

I think this is worth implementing fully before publishing the sim, since it pedagogically important.

[matthew-blackman]

This has been implemented and is looking/behaving great. Closing.