Some of the most challenging, rewarding, and fun sounds to record are those within the vast spectrum of fluids. Wet, sticky, viscous, mushy; the tactful use of fluid sounds can reinforce the realism and impact of a scene, or just be the punchline of a joke. In order to effectively communicate an idea to an audience, there are a few challenges in recording fluids to consider before dipping your toes in. While most of these considerations are technical in application, they all serve to realize an idea and bolster the narrative. For live-action projects, capturing the complexity of fluid sounds on location can often range from impractical to impossible, which is where foley steps in.
Picture a couple of people jumping into a river from a waterfall. Cut to a close up of their bodies splashing into the water below. If we wanted to record this on location, we probably wouldn’t get much more than the powerful white noise from the crashing waterfall, making it undoubtedly difficult to capture the sound of the splash as they enter the water. There are a few ways around this issue. One may be to find another location without a waterfall, thus being able to more easily isolate the specific splash sounds. In any exterior situation though, you run the risk of picking up unwanted background noise. Arguably the most efficient way to gain the best control over your sound is to record in a foley studio. There are some considerations to make when recording water in a studio. A way to alleviate some background noise in your fluid recordings is mic placement. Generally for exterior sounds like our river, we won’t hear much reverb and a close mic technique will work great for capturing as clean a sound as possible.
an example of a hydrophone
Now, say the camera follows the diver under the water. Underwater sound has very specific characteristics that audiences have come to expect. So how do we capture that ‘below the surface’ character? Put a microphone under water? While your gut instinct may tell you to NOT put electronics in water, there are microphones manufactured for exactly that, called Hydrophones. Hydrophones are unique and you can make one for yourself with a few simple items. The Hydrophone may not produce the desired sound you’re after though, as sound travels through water depending on a number of factors including temperature and pressure. Also, hydrophones are made with piezoelectric sensors, which are very good at capturing changes in sound pressure but not the best for capturing a wide range of the sonic spectrum. Take a listen to this recording of a hydrophone underwater.
You will hear it sounds slightly distorted and thin – not generally what you would expect listening underwater to sound like. Another method we often use in foley is we will record the sound above the water and EQ it using a wide bandpass filter in the midrange to emulate that muffled underwater sound that audiences are used to hearing. Remember to take precautions when using microphones or any electronics around water and do not submerge equipment that is not designed for that purpose.
Half of good foley is footsteps and another fluid element we occasionally come across is footsteps in water. Let’s say the characters in our film are walking along a beach. They walk through the sand and occasionally some water laps at their feet. This is a good time to use the process of layering. If we record sand footsteps and then add water movement on a separate track, we have the ability to adjust the amount of each independently, allowing us to control a more natural and varied sound. Another example of where one might layer fluid sounds is to emphasize something that may not naturally make all that much sound. Layers of a wet rag squish can create some wonderfully gory, over the top blood sound effects (if our film suddenly took a dark turn). Also, consider layering two tracks of water movement and pitch shifting one of them to give you a richer texture for a large body of water.
It can be tricky finding the right vessel for your fluids to make the sound you’re after. For instance, someone taking a sip of a drink sounds very different if they are drinking from a wine glass versus a coffee mug. To add more complexity to that, even the type of liquid can have an effect on the sound, as there are many people in the industry who can hear a difference between sips of wine versus water. If one were to use a metal bucket for water foley, you may end up with a thin, resonant sound where you may be after something more open and full. The height of the liquid in your vessel is also important. The more fluid there is in the container, the less resonant the container will be. The material, size and fluid level of the vessel makes a huge difference and it may take some tedious experimenting with those combinations to find the right sound.
If sound editing is more your thing, or if you don’t have access to some recording equipment, another great option for fluid sounds is from sound libraries. Field recordists such as Tim Prebble put a lot of time and hard work into recording great sounding and varied sound effects for multiple applications. Check out Tim’s library of water foley here for some good examples of what you can accomplish with field recording fluids or to supplement your own sound effects library.
There are many ways to record fluids; have some fun experimenting with different mics and mic placement, different fluid vessels and even the fluids themselves to come up with something unique and creative that adds to the character of your soundscape.