It’s been said before, but that doesn’t make it less true. Bad audio can ruin good video. Video producers can sometimes get wrapped up in making their videos look great while neglecting the audio side of things. Don’t do this! Okay, enough lecturing. Let’s talk about some best practices that you can put in place when creating and mixing audio for online video.
Get High-Quality Audio for Your Online Creative Projects
1. Recording Audio
You may not be recording your own audio for all of the video you create, but when you do, it’s important to record it will. This means, please don’t record audio on your mobile phone. While it’s true that the quality of modern phones has gotten better, the audio recorded from a tiny mobile phone mic input is not up to snuff with professional gear.
You’ll want to use a professional microphone, or many, and professional recording gear. We won’t tell you which pieces of gear to purchase, but pay close attention to the types of microphones to use for your specific needs.
Two things to think about are polar patterns in microphones which are basically the areas around the microphone that pick up audio. As an example, a microphone with a cardioid pattern picks up sound in a heart shape, where the audio comes from most sides of the mic, but not the back. A shotgun polar pattern picks up a majority of its sound directly in front of the mic, and some audio comes from the back, and a little from each side.
The other thing to think about it the type of microphone you’ll need based on the setup. For example, a lavalier microphone is a tiny mic that clips onto a person’s shirt and is often perfect for interview footage when the mic needs to be hidden. A shotgun microphone is also good for hiding as it can be held above the scene facing down.
You don’t have to pay hundreds or thousands of dollars for microphones, there are some great mics for $100 or less, but be sure to read up on reviews and try and find audio samples before purchasing so you can make an educated decision about which mic will suit your needs.
Great microphones are important, but you also need great recording gear. You can’t just plug a quality mic into your computer and record. You need an audio interface. For recording directly to a computer, you’ll want an interface that records at least 24-bit / 96kHz audio.
The first number “24-bit” refers to the bit depth of the audio. This is similar to video bits. If you’ve ever heard the term “8-bit” used, it refers to 80’s era video and audio that was low resolution because it only carried 8 bits of depth per sample. 24-bit audio has a much higher resolution and this better sound quality, and it is now the industry standard for online audio.
The second number refers to the sample rate, meaning how many times audio is sampled per second. This is a bit like compression in video. The higher sample rate, the more data you have to work with. Some recorders will go up to 192kHz in sample rate, but 96kHz is plenty for online audio.
If you are recording on the go, consider a portable recording device like the Zoom H6 which houses a 24-bit / 96kHz recording interface, 4 microphone inputs and a couple of attachable mics into a portable device. There are several other portable options on the market that will work well too. Just be sure to read reviews and choose carefully.
2. Mixing Audio
When mixing audio for online video, there are a few things to take into account. First is stereo versus mono versus surround. Most likely you’ll be outputting your audio for stereo. Note, that YouTube does accept 5.1 surround mixes, but Vimeo does not.
If you simply have a sound of a talking head that is mixed right down the center, you can output in mono and save yourself some file size, but if you have any music or sound effects that were output in stereo, it’s a good idea to output your audio in stereo as well.
A topic of great debate for audio online is where to limit the volume or peaks. Some people suggest letting audio go to 0dB. This is the point when an audio clip is the loudest without “clipping.” Clipping is the point when audio gets distorted and begins to sound bad. Other people suggest limiting audio peaks to -6dB.
This ensures that your audio will not get into clipping territory at all. You can attempt to limit your audio to -6dB or 0dB by closely eyeing the audio meters. But a more exacting way to do it is by adding a limiter to your audio. You can set the max level of output this way and make sure your audio doesn’t go above that.
Another thing to think about when mixing your audio for online video is where the audio will be played back. Most people watching online video will be watching on a mobile device like a phone or tablet, on a laptop, or at best through computer speakers. They may be using headphones, but those are often earbuds that aren’t all that expensive.
You can mix your audio using high-quality monitors, but be sure to also playback your audio using the cheapest reference you can. Play it back on your own mobile device or laptop to be able to understand how many people will hear it. You may be able to clearly hear a voice over the music on nice speakers, but find that the voice gets lost when listening back on cheap speakers or earbuds.
3. Output Audio
Although you can output audio in whatever compression format you choose, YouTube and Vimeo compress audio in the AAC format. It’s a high-quality audio compressor that keeps file size down while maintaining quality. If you are planning to house video online, it’s a best practice to use AAC for your audio.
Additionally, there is a range of options for bit depth and sample rate on export. But YouTube and Vimeo suggest either the industry standard of 48kHz sample rate or, in the case of YouTube, 96kHz. If you are going to post to multiple sites, 48kHz is a good idea.
Taking into account all of these things when producing, recording, mixing, and outputting audio for online video will give you a better result and add to the overall quality of your video.