"How to get great production sound- the basics"

I didn't get a chance to read the whole thing, but proper boom technique and proper mic placement are key, and neither of the photos in the blog post display those things. You might want to fix those.
 
Sadly sound does not travel in a straight line either, light does but sound can bounce and be deflected and resonate in all directions with phase and frequency changes as it goes!
 
Both sound and light travel in a straight line until interfered with by an object. The point I was making is the importance of having the mic on axis.
 
mainstreetprod said:
Both sound and light travel in a straight line until interfered with by an object.
Click to expand...

Here's an experiment. Go out at night to the corner of a building. Stand on one axis of the corner, about 6' back from the corner, and have someone else stand about 6' back from the corner along the other wall. You both should be facing the corner. Have them turn on a high-powered flashlight or even a head from your lighting kit and shine it straight ahead. Can you see the light? Does it illuminate your face from around the corner?

Now, have the other person pay some music through a small PA system or bluetooth speaker. Can you hear the music?

The light won't hit your face from around the corner, but you'll hear the music. More specifically, you'll hear the lows of the music more than the highs, because bass frequencies bend more while high frequencies travel more line-of-sight.

Sound and light are inherently different and they do not move in the same ways. Light is emitted as photons (light particles), so they travel straight ahead in the direction they were sent (until they're reflected or absorbed). Sound, on the other hand, is nothing more than vibrations emitted from the source. Those vibrations, relying on existing molecules in the air, disperse widely and in all directions.
 
The reason sound behaves different than light is because it is many orders of magnitude longer wavelength.
That corner of the building refracts sound waves whose length is measured in kilometers.
But it doesn't affect light whose wavelength is measured in Angstroms.
 
If we want to go down the physics rabbit hole and be really correct Light is a particle with some wave like properties. It can have frequencies as low or lower than sound, you just won't see them. It travels really damn fast and it travels like a particle. It is actually never "reflected" because it can't go slower than the speed of light so it can't actually "bounce". What it does is get absorbed by the object as energy and reemitted as a new photon.

Sound on the other hand is a pressure wave. It doesn't wiggle but compresses particles in whatever medium it is traveling in. As such is is always radiating in all directions. It can bounce and it travels at widely varying speeds. It is a physical phenomena not a particle and so it is limited by what it can act on. The frequencies that are possible depend on the media since there is time associated with compression and expansion. It can go very low but can't go particularly high in air because of the limitations of air to compress and expand.

For all practical purposes one can think of light only traveling in a straight line and sound radiating in all directions, all the time. It's the "all the time" that is the big difference. If you put up a flag you will block light. Some will bend around the edge because of the wave properties but not a lot. With sound you will get a bit of a decrease but not a lot because as the pressure wave passes the flag it is radiating in all directions, that "all the time" part. So as the wave passes the flag the direct wave was blocked but the part not blocked is radiating forward backward and sideways and you get most of the signal.

Another way to think of it is that light is a stream of particles, where acoustic sound is a wave that is compressing bunches of particles as it goes. The particles that sound is compressing happen to be in the path at the moment the wave came through, but they were all headed someplace else and they keep going where they were headed carrying some of that "sound" with them.
 
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