Understanding EQ and Compression

Capturing clear audio can be challenging enough in its own, even if you're an experience audio engineer. And often the best audio can benefit from some slight cleanup in post-production. Now, I'm not saying it's good practice to rely on post-production efforts to fix glaring audio mistakes. As video producers, we take a lot of care in making sure we're capturing the best image in-camera at the time of filming and the same should be true for capturing the best audio.

With that said, there are two audio tools built into every video editor that, when used correctly, will be your best friends: Equalization and Compression. So what do these tools do exactly? I'll give you a 30,000 foot view here, and we'll unpack things further with a real life example in the video.

Equalization (EQ)

Every single audio wave falls within a certain frequency range. Similar to a color spectrum, different sounds occur at difference frequencies and depending on your audio source (dialogue, music, sounds effects, etc.), you may need to increase or decrease the gain of these frequencies to remove distracting or boost weak tones.

An equalizer give you complete control over the frequency range of each audio wave. With easy-to-use sliders, you can "sweep" through each range while your audio playback to identify problem areas and address them at the source.

Compression

Recording audio at proper levels is so important to the final edit, but microphones can only take you so far, especially when filming in a noisy environment. Further still, audio is dynamic. Think of our speech for example. We use inflection and volume control to create intrigue, drive home a point and keep our audience engaged.

A compressor is designed to create a more consistent signal. With parameters such as threshold, attack, ratio, release, and output gain, you'll be able to 'squeeze' the waveform by bringing down the louder parts and bringing up the lower parts. This way, your audio will cut through any background music and sound consistent to the listener without any awkward dips or spikes in volume.

Audio production is certainly a blend of art and science. Less is more when making adjustments and use your visual meters as your ears can deceive you, especially when editing for extended period of time.

Check out the video for a real life example!