What is foley work?

Foley work recreates particular sounds for which you do not have the original source of.

The art of making sound effects for movies, tv, video games, and so on, or "Foley" effects, is just as if not more exacting then musical projects. With music you have the expectations of creating something original, which allows you a certain freedom, wheras Foley effects have the expectation of perfectly matching sound qualities everyone is already familiar with. We all know what footsteps on tile sound like, breaking glass, opening doors, and so forth, and expect those sounds to be recreated without distraction for our visual enterainment.

Trying to make your own foley design is always a fun little exercise because it allows you to think about how similar some sounds can be even if they come from completely different sources.

Here are some of the key considerations when attempting such work.

Locational consideration

Panning

When it comes to normal modifications we wouldn't think of as "effects" there are a few simple aspects to consider, namely the volume and balance of an audio clip. Panning and fading audio is a simple enough operation and the cues for how adjustments can be made should come from simply watching the footage and taking into acount two things.

  • The distance from the viewer / camera. This will affect the amplitude / gain.
  • The left to right position within (or even outside) the frame. This will affect the left / right channel panning.

Even if you're not working with something like 5.1 or 7.1 audio you can even still simulate backward and forward movement in stereo. The obvious way would be to make anything closer to the camera louder but we can also simulate the sound wrapping around our ears as if were coming from behind through stereo separation.

Reflection & Filtering

Sound attenuation describes the rate at which amplitude descreases (exponentially) over a certain distance.

It's not enough to simple "place" the sound within the scene. We must also consider how the on-screen action and environment alter the sound. Typically the next consideration after location will be echoes & reverberation. Echoes refer specifically to a delay in a sound caused by both bouncing off a surface and the time involved. Reverberation describes the way a sound persists after the initial emission without the audible distinction of a return sound. They have slightly different definitions but for the most part are affected by the same factors. Because of that we'll only consider to what degree any given sound is absorbed or reflected off of surfaces within our scene.

So the key factors to reverberation will be the average distance of surfaces surrounding the source and the density of those surfaces.

While some situations might call for others you can typically emulate most any given environment through three effects.

Reverberation

Frequency Passing (Filters)

Delay

Reverberation

Two main facets of reverberation are the amount and the time.

  • Softer surfaces absorb more sound (vibrations) than hard srufaces.

As a sound travels it is absorbed into the matter is is traveling through (solid or gas). Sounds that start with higher amplitude have more energy to disperse before they lose all influence.

This is why many musicians will hang blankets or other soft cloths in makeshift studios to help eliminate unwanted echo or reverb effects from hard walls, floors, and ceilings.

There's a sweet spot where matter is soft enough to reverberate but not so soft that the intitial force is entirely absorbed.

Getting an impulse response for a "convolution reverb" is incredibly useful in this area since you can emulate the reverb or echo effect of a practicular space as opposed to a generic, linear reverb effect.

Filtering Frequencies

Again, a sound travels it is absorbed into the matter it is traveling through (solid or gas). Since lower freqencies have wider wavelengths they can help sustain the amplitude a bit longer than high frequency sounds which don't reverberate as much.

The degree to which this happens depends largely on the medium the vibration is passing through. This is why you can hear the bass levels of a passing car stereo clearer through your house walls but when only traveling through air you hear the higher pitches of the headphones of the person sitting near you.

This of course does not mean that you shouldn't have high fequencies in your ambient sounds. Given enough amplitude *any* sound will become clearer. It's just a matter of asking yourself whether or not a sound has the amplitude to justify keeping in the higher sounds. As a rule of thumb, considering that a sound runs the frequency gamut, start with a low pass and lower the frequency threshold until you reach the right filtering level.

  • Lower frequencies penetrate surfaces more than higher frequencies and so will not reflect to the same degree. Even given the same medium, low frequencies travel farther than higher frequencies.
  • Some will have the impression higher frequencies allow for better directional location.

So consider if a sound might bounce multiple times. Multiple bounces off solid surfaces may filter out low frequencies.

Delay

A "delay" plug-in will of course be used to simulate echo effects within the environment. There's really not much to be said about it.

  • Larger environments induce longer delays.

If your chosen program has an "echo" effect than it can work just as well, and in a similar way, just be aware that some "echo" effects work by basically combining reverbation with delay effets. Unless it has many options then seperate reverberation and delay effects may give you better control.

The larger the space the longer it will take for a sound to reflect back to the point of origin. When using an echo effect (or maybe a reverb effect with low reverb and high latency) you'll vary the delay based on the median distance of reflective surfaces. If surfaces in scene are at different distances you may even utilize multiple "bounces".

For the most part what we percieve as an "Echo" however is rare. You will probably only want to actually add the effect after taking into account the other two questions.

...and back to panning again.

Now that you've thought about frequency effects, know that it *may* affect your locational panning as well. Because of the way vibrations work it is often easier to locate higher frequencies than lower frequencies. Shoorter wavelengths cover a smaller area and appear as a more direct source.

This is why echolocation used by dolphins and submarines typically use wavelengths in the higher range. If you've ever heard a car radio as it drives by outside then you might have noticed that the higher pitches come from the direction of the car while the lower bass seems to reverberate throughout the room.

So what does that mean for us? Basically if you're adding sounds to a scene consider whether or not they use the higher or lower range and balance them accordingly. Lower sounds might rumble slightly throughout each channel while its the higher ones that will pan between channels more distinctly.