We have a good reason to be stressed if we hear the rumble of an earthquake beneath our feet or the growl of a nearby bear. These sounds signal that our lives are in danger, and that we need to act fast to keep ourselves and loved ones safe.
Our ancestors needed to hear a nearby predator's roar or a life-threatening storm coming towards us, so we've evolved to become tense when we hear certain low-pitched sounds. Here's how to use the power of these low frequencies to guide your audience:
Communicate How Heavy, Large, and Close an Entity Is
Low frequencies can reinforce the size and weight of an incoming object or enemy. Think of the Colossi in Shadow of the Colossus, the titans in Attack or Titan, or the boulders in Sen's Fortress in Dark Souls. We believe that they are threatening and massive because we hear low pitches in their movements. Also, the closer a sound is to us, the more low end we hear.
Hide Threatening Sounds Within a Larger Sound Effect
Sound effects are comprised of multiple layers of other sounds that are combined seamlessly. If you want an enemy in your game to scare your players, your Sound Designer can mix familiar, intimidating sounds into their cries. For example, the T-Rex's roar in Jurassic Park was created with sounds of a baby elephant, a tiger, and an alligator.
Raise Tension Without Your Audience's Awareness
When frequencies are low enough, they are more felt than heard. Think of hearing the bass thump in the car next to you when you're waiting at a traffic light. These really low sounds (<200 Hz), can be played on a subwoofer blatantly or subtly. In David Lynch's Lost Highway, a low rumble plays ominously in the background as the villain approaches the protagonist.
Save Sudden Bursts of Low Pitches for Key Moments
Low pitches can communicate that a laser's blast packed a punch, or that a rocket just launched. Your player character's final attack in a combo can have have a low frequency layered into it to communicate that you landed a deadly attack. However, they only add emphasis if there is contrast. Reserve using this overt low end for critical parts of gameplay.
In Conclusion
We can utilize low frequencies to guide our players into the emotional state that we're aiming for. We can give them important information, such as how much an incoming enemy may do, with deliberate sound design. Contact me if you want help with that for your game.