The Audio Signal
The further you get into editing film and video, the more you realize audio, not always the image, is the key to making your film appear “professional.” Viewers are often more lenient about the images they see versus the audio they hear. At the base of any good audio mix is well captured audio. DO NOT simply brush aside audio recording in favor of the images. If your audio is recorded properly on set, you’ll have great flexibility when it comes to mixing in post production. If not properly recorded, you’ll most likely have few or no options.
Any recorded audio signal is broken into a few basic parts. Your low frequencies, or the Bass, the mids (which falls between the low and high frequencies, and your high frequencies, called the Treble.
Adobe Premiere's Parametric EQ
To adjust the different frequencies of an audio signal, an audio mixer uses an Equalizer. An equalizer adjusts the power of different bands of frequencies to emphasize one over another. While there are many different types of Equalizers, they all operate on the same principle. When mixing my own projects, I use a specific equalizer called a Parametric Equalizer. (You can find this in Adobe Premiere Pro and FCPX) This type of equalizer gives you power over the three main audio components: the various frequencies of the audio signal, the power (gain) of the audio signal, and the bandwidth (Q), which adjusts how wide or narrow you want the audio signal to be. I prefer working with the Parametric EQ because, in giving you control over just the main three components of your audio signal, it also simplifies the interface. As I’m not a professional audio mixer, I find it very easy to get lost in more complicated equalizers.
Using Your EQ
In most basic audio mixes, you’re using equalization to accomplish two things. First, eliminating unwanted frequencies from your individual audio signals. Second, balancing those various signals so they blend together and are not competing for your attention. In a sound mix, you generally want to look at first removing frequencies from an audio signal before trying to boost a signal’s power. For vocals, I normally start off removing the top and bottom most frequencies to get rid of any low end rumble or high end squeaks your microphone may have picked up on set.
Next, I focus on what I feel is missing in the person’s voice. If someone’s voice rests at a higher frequency, it can sometimes sound too “thin”. In this case, I’ll either look at removing frequencies in the Treble, or boosting frequencies in the Bass to add body or thickness to their voice. Conversely, if someone’s voice rests at a lower frequency, it can often be “muddy” and hard to understand. In that case, I’ll either look at removing frequencies in the Bass, or boosting frequencies in the Treble to add clarity.
Now let’s add music into the equation. A lot of the time, newer or inexperienced filmmakers will simply place music underneath their dialogue and adjust it’s volume up or down. The problem with this is, dialogue, sound effects, and music are all equally important to a film. Simply adjusting their volume emphasizes or deemphasizes one over the others. Additionally, the constant volume fluctuation can be distracting to the viewer. To blend music into the mix, I once again go back to my Parametric EQ. I remove the frequencies in the music that the dialogue tracks need to take up. This creates a “music bed” that has just as much power volume as my dialogue, but is emphasized in different areas of the sound mix.
Things to Keep in Mind
First, once you’ve found a comfortable volume level to listen at, keep it there. Constantly adjusting your speaker or headphone volume resets your hearing. Second, know where your video or film will be viewed. A Youtube video played back on computer speakers is going to have a much more compressed sound mix than a film being heard in a movie theater. To edit for these different distribution platforms, it’s best to mix with somewhat equivalent hardware. For instance, headphones or computer speakers for internet videos, or more professional audio monitors for things going to home video or theaters.
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As director of photography at Creative Liquid, Zack’s in charge of making our videos look beautiful and coordinating our crews. He earned his B.A. in filmmaking and minor in photography from George Mason University. When not on set for Creative Liquid, he spends much of his time making his own short films.