

Have you ever wondered what makes up a sound?
Sound is all around us all the time. This constant sensory input, for those of us who are not deaf or hard-of-hearing (please see note at the bottom of this post about accessbility), is an important part of how we experience and process the world around us. How we experience sound is significantly affected by the two major elements of sound: frequency and amplitude. Not only do these play a significant role in our daily experiences, they also have an impact on how we record sound and are the parts of sound we manipulate when we are editing audio.
To put it simply (for now, scroll down for a more technical breakdown of sound):
Understanding these parts of sound is very important to understanding how we work with sound when producing videos and podcasts.
The importance of amplitude/loudness is pretty obvious. If the sound isn't loud enough, we can't hear it. If the sound is too loud, it can be annoying, overwhelming, and even painful.
But what is the importance of pitch? The pitch of a sound actually tells us a lot about our physical relationship to the source of the sound. Lower pitches travel further and pass through objects more easily than higher frequency sounds. Every sound we hear, including each other's voices, is a complex combination of different high and low frequencies. The frequencies and how we hear them can be impacted by the environment. All the pitches that make up any one sound are important to the experience of that sound and the removal or quieting of any of them can change our experience of that sound. So, for example, when you hear someone talking on the other side of a door their voice sounds different because the higher frequencies in their voice do not carry through the door as well as the lower pitch parts.
When you combine the effects of amplitude and frequency things get a little more complicated. When high pitch sounds are quieter they sound like they are further away, because high pitch sounds/high frequencies don't travel as far or through objects as well as low pitch sounds/low frequencies. (It's why the kid in your elementary school class with the deep voice always gets caught talking in class... because their voice carries further and more powerfully than the kids with higher pitched voices.)
That is how we can manipulate frequencies in our editing: controlling the amplitude of frequencies. One of the tools you have in almost every editing software that does just that are equalizers. An equalizer allows you to raise or lower the amplitude of different frequencies, which can be extremely helpful in your editing process.
Some facts about sound to help you avoid potential audio issues and improve your audio in editing:
How does this affect your recording process?
What can you do in editing to manipulate frequency to improve your recordings?
The equalizer can be a powerful tool for helping make sure voice recordings are clear for listeners:
Those are some practical ways to work with sound and how you can manipulate amplitude and frequency to improve your recorded audio. But let's get a little more technical here for those of you who are curious.
It's important to understand that sound is a wave. Technically it's a pressure wave in a medium. We can visualize this wave with our sound equipment as a sound wave. When you look at your audio in Adobe Audition, Adobe, Premiere, Avid Pro Tools, Avid Media Composer, Final Cut Pro X, Logic Pro X, DaVinci Resolve, or any other program with the ability to edit audio, you're looking at a visual representation of a sound wave. Amplitude and frequency are on display in that visual representation. Amplitude describes the power of the wave, which is represented by the height of the sound wave. Frequency describes the speed of the wave or the distance between the start and end of each wave. This is an oscillation and the number of oscillations per second is the frequency.
We experience the height and speed of the wave as volume and pitch respectively. The greater the amplitude, the larger the wave is, which makes for a louder sound. We measure this amplitude in decibels and this is typically what you're manipulating the most: the loudness of the sound. You can increase loudness without affecting our other part of sound, frequency.
Pitch corresponds to the frequency, or speed, of the wave. We measure frequency in hertz (Hz) or kilohertz (kHz which is used to describe thousands of hertz). The higher the hertz, the more oscillations per second, the shorter the distance between the waves. The shorter the distance between the waves, the higher the pitch. A high frequency sound wave, let's says something around 15,000 Hz (also known as 15kHz) would be experienced by us as a high pitched sound while a low frequency sound wave of, for example, 100 Hz would be experienced as a low pitched sound. You can increase or decrease frequency without affecting the loudness.
An understanding of the basics of the parts of sound can significantly improve your sound in both recording and editing. Hopefully, the facts and tips we shared above will help to improve all your future productions. Before we wrap up, though, here are a few fun facts about amplitude and frequency:
Special note: To make your project accessible to those who are deaf or hard-of-hearing, you'll want to learn about Subtitles for the Deaf or Hard-of-Hearing (SDH.) Here's a good place to start: https://blog.ai-media.tv/blog/what-is-sdh
For more information, tips and tricks visit www.mnn.org/learn for free workshops, professional courses, filmmaking bootcamps, and more resources to make your productions successful.