Very nice, though one thing to note for readers is the pictures are of transverse waves like you’d see in a vibrating string. Sound waves are longitudinal pressure waves which propagate outward in expanding spheres from the source of the noise. The loudness of a sound you hear corresponds to the pressure and frequency it imparts on your eardrum at the point of intersection between that expanding sphere and your ear.

This pressure is directly proportional to the surface area of your eardrum on the surface of that sphere. As you may or may not recall from high school geometry, the surface area of a sphere is 4pi*r^2. If you consider the pressure of a sound wave as being evenly spread out over the surface of that expanding sphere (assuming an ideal gas), then doubling the distance from the sound source will quadruple the surface area of the sphere, thus decreasing the pressure your eardrum experiences by a factor of four! Sounds from very far away rapidly lose pressure (so are quieter) without the aid of constructive interference to boost them.

If you’ve ever heard an echo, you know that sounds can bounce off solid surfaces. Combined with the phenomenon of constructive interference, sound reflections can achieve a great deal of amplification. This is the principle upon which architectural acoustics is based.