What are they and what do they mean for Podcasters?
Anyone's who's watched TV or listened to radio is familiar with broadcast standards, you may not be consciously aware but through years of exposure, your ears have been trained to receive audio information from broadcast media in a certain way.
Sometimes you may find that something is annoying to listen to either because it's too loud, too quiet or there's too much variation in loudness throughout the audio. This may be because the audio you’re listening to is violating some broadcast audio standards. I will briefly explore these broadcast audio specs and how they affect you as a Podcaster or Vlogger.
You may know about LUFS and LKFS, or unlike me, you have a life and that means absolutely nothing to you. These are the measurement units for loudness, there's more but it's these that matter for podcast creators. The purpose of these is to make sure that when you listen to two different broadcasts, either TV, Radio, or Podcast, you can do so without fiddling with your volume controls because the average and peak loudness levels are the same.
LKFS stands for (Loudness, K-Weighted, referenced to digital Full Scale), averaged out throughout the audio track. It was what was initially used by the EBU (European Broadcasting Union) However, over time they discovered a problem.
It was too easy for long quiet sections of audio to bring down the average measurement. So in came LUFS (Loudness Units, relative to digital Full Scale) The main change being the introduction of a gate that would stop data being taken into account if the level dropped below 8 LU(Loudness Units).
This is because consumers judge the loudness of any particular piece of audio based on the loud parts, so this gate was introduced to make sure quiet sections would not skew the overall measurement.
How does this affect your podcast?
Basically what you need to know is that the podcast industry has mostly standardized on -16 LUFS. This is the loudness level that Apple Podcasts ask for and many of the most recent podcasts mostly use -16 LUFS so that they sound the same loudness-wise. LUFS is expressed in negative numbers, so -26 LUFS is quieter than -16 LUFS for instance.
Broadcast radio and television use -24 LUFS in the US, -23 LUFS in the rest of the world: so if you were to take an audio file made for broadcast radio and upload it as a podcast, it would be too quiet.
In conclusion, to ensure that you are putting out the highest quality content, you have to make sure that when you are editing yourself or when you get audio from your audio engineer, it meets these standards before you upload it. There are many tools you can use to analyze your levels, there is the Waves WLM Plus Loudness Meter plugin or my personal favorite Izotope insight 2 plugin, check those out.