This time on the audio journey we look at distortion or clipping. Distortion is when the audio goes above the maximum ceiling of 0db and will sound horrible.
There are two different kinds of distortion, analogue and digital. First we’ll deal with analogue.
Analogue distortion most commonly occurs at source and this means that the signal coming into your DAW is too hot, or too loud. This can be caused simply by the gain on your mixer or pre-amp being set too high. This type of distortion is most often non-recoverable and the audio will need to be re-recorded with better attention set to the gain control.
Digital distortion is distortion which occurs within the DAW. Providing you are working in 32 bit floating point you can easily recover digital distortion. Say you’re mixing out a multi-track session and you’ve laid your voiceover over some music and the output exceeds 0db. If you are working in 32 bit then you can mix this down and recover the audio by normalising it back to 0db or below. This is true if the audio file has been saved or not as 32 bit allows for sufficient virtual headroom in the audio that the file can be recovered and won’t suffer the ill effects of distortion.
When recording voice into your DAW many people will give different ideas of the maximum levels you should be looking to hit. The simple truth is as long as your audio doesn’t exceed 0db when recording in your audio will be fine. It’s worth taking a moment to run a few level checks before commencing a voiceover or podcasting session to ensure that your audio doesn’t clip so you are recording good audio. It’s better to record too quiet and boost in post production than it is to get close to distortion as all it takes are a few words said louder and you’ve introduced analogue distortion into your recording.
If you record with a maximum input of -3db, you’re fine. Equally if you record with a maximum input of -20db which it’s very quiet audio you can normalise this as your first step in post production and your audio will be fine.