A lot is said on the topic of recording audio. Which microphone to use for recording this or that. Where to place them, how to hide them from your shot, and so on. But once you’ve got all your audio recorded and you’re editing your video, what do you do with all of this sound? This video from Pond5 shows 5 basic, but essential, audio mixing techniques every filmmaker or YouTuber should know in order to get the best final result.
It is quite a short list, and four out of five of these techniques I use in every video I make. I’ll probably start experimenting with the fifth. You may already do some of these, but if you don’t, you should.
Adjusting Gain
Gain essentially controls the volume level of your audio. All of your sound should typically stay between -24 and -6 dB. But there are more specific typical guidelines for different types of sound.
- Dialogue: -18 to -9 dB
- Music: -22 to -18 dB
- Sound FX: -20 to -10 dB
- Nothing at all at or above 0 dB (it will clip and be distorted)
This can be done directly within editors such as Premiere Pro, or you can shell out to external applications like Adobe Audition, depending on your needs. Personally, I prefer to do it in Audition when processing the original audio recordings to reduce hiss and background noise or enhance voice frequencies.
Keyframing Levels
This is why the guidelines above are ranges, rather than specific individual targets. Sometimes you may need to raise or lower the gain of one track over another at different parts of your video. For example, if you have a shot with no dialogue, you may want to bump up the music. But as soon as somebody starts talking, you’ll want to lower it again so the voice can be heard.
Ambience/Room Tone
This is one I struggle with, as I often forget to record room tone or location noise, but it’s something I’ve been working on. It’s good practice to record a good 30 seconds or so of room tone or environmental noise whenever you shoot a video somewhere. This allows you to maintain that tone in areas where there may not otherwise be any.
For example, you may want to use this section at the end of a clip to fade from room tone to music. Or to fill in gaps in dialogue while footage is playing or during times of inconsistent background noise. Maybe you need to record a voiceover for a particular segment after the fact. Having an environmental recording of the ambient noise helps to make those things a little more seamless.
Room tone can also be used to help capture a noise print for noise reduction where the environment’s noise isn’t wanted. Like an air-conditioner hum.
Crossfades
This was something I discovered years ago purely by accident. I hadn’t seen it in any videos, but I was experimenting with transitions to help get rid of the “pop” you occasionally hear where two clips butt up together.
There are a variety to pick from in Premiere, like Constant Gain, Constant Power, Exponential Fade. Other applications have their own versions, too. In Premiere, I prefer to use the Constant Power as I find it provides the smoothest transition between two clips. It doesn’t need to be a long transition for something like this. I typically go with 2 or 4 frames – covering 1 or 2 frames on each of the adjoining clips.
It’s also extremely handy when you need to extend music tracks. Simply cut the audio track on a beat, start the next clip on a matching beat, and then use a few frames of Constant Power to make the two blend seamlessly together. Nobody will ever know that song isn’t really 7 minutes long.
Panning
Panning the audio in post, to create a stereo effect isn’t something I’ve done much. If I’ve used a stereo mic, then it’s just picked it up naturally, but mostly I record with single, mono mics to both channels (or to one channel and I duplicate it to the other). I think for my own content, and the content I produce for DIYP, I just haven’t really needed to use this technique much.
Depending on what you shoot, though, this can be a great audio effect for your videos. The example shown in the video is perfect to illustrate the kind of situations where it can be beneficial. But it’s not just for things moving across your shot. You could also do this to signify things happening off-camera, too. Perhaps to make it sound like somebody’s talking or shouting from the next room. Maybe there’s a crash on the street just outside the window.
The first four techniques above, I use in just about every video. I do my gains slightly differently, but beyond that they’re the same principles. The exact process will vary from application to application. Premiere will be different to DaVinci Resolve will be different to Final Cut Pro, etc. But they all offer the tools to let you achieve these basic audio techniques.
Luke Wilson