Podcast Production
October 17, 2023

What are LUFS? A simple guide for podcasters

Resound.fm Team

You know what really ruins a podcast listening experience? When you press play on the next episode and the volume unexpectedly blasts your ears. It’s annoying, especially if you’re using headphones.

Inconsistent playback volume between various podcast episodes is the result of the inevitable variation in recording technique and post-production processing across the industry. 

The solution? An industry standard volume for loudness.

This standard level of loudness is measured in LUFS (Loudness Units Full Scale) and in this blog post we're going to break down exactly what you need to know about LUFS as a podcaster. 

What we’ll cover

What are LUFS?

Simply put, LUFS are units of audio loudness. LUFS is short for Loudness Units Relative to Full Scale, which means the maximum level a system can handle. LUFS are used to set targets for audio normalization for podcasts, movies, TV, radio, and music streaming. 

LUFS is a standard that measures audio loudness in a way that aligns with human perception. Unlike traditional peak measurements that focus on the highest levels, LUFS assesses the average loudness over an entire audio track by weighting frequencies based on human hearing sensitivity, resulting in a measurement that mirrors our subjective experience of loudness. 

For podcasters and broadcasters, using LUFS ensures content is delivered at a consistent perceived volume, eliminating the need for listeners to frequently adjust their volume controls.

The Audio Engineering Society recommends a standard loudness between -16 LUFS and -20 LUFS. However, individual platforms have their own preferences. For example, Apple Podcasts adjusts podcast volumes to -16 LUFS for consistency, while Spotify sets a maximum limit of -14 LUFS.

Confused yet? It’s a complex topic. But before we dive deeper let’s take a step back and talk more about why loudness matters, and what it even IS in the first place. 

Why does loudness matter?

Loudness is one of those things that listeners only notice if it's bad. And that’s exactly why it matters. 

A consistent loudness level matters so that podcast listeners don't have to constantly adjust the volume when listening to a single podcast episode, different episodes of the same show, or different shows entirely. 

Plus, if your podcast is too loud, it can clip, leading to distortion. And if it’s too loud or has a lot of dynamic range (i.e., big differences between the loudest and quietest parts), it can lead to listener fatigue. 

Lastly, different podcast platforms, like Spotify and Apple Podcasts, have their own audio standards. By sticking to loudness standards, podcasts ensure they're perfect for any platform, always sounding their best.

In summary, it’s a critical (though technical and boring) part of making a great podcast. 

What is loudness? 

Loudness refers to the perceived intensity or volume of a sound to the human ear. Unlike pure volume, which can be measured objectively using instruments, loudness is subjective and can vary based on the listener's experience and the sound's frequency and duration.

In the context of audio production and broadcasting, such as podcasts, loudness is crucial because it ensures that audio content is perceived at a consistent volume level by the listener, regardless of how it was originally recorded or produced. This is especially important in ensuring that listeners don't have to constantly adjust their volume controls. Standards like the LUFS (Loudness Units relative to Full Scale) have been developed to measure and standardize loudness in broadcasting and production.

Consider two scenarios: A host who randomly bursts out laughing and the steady voiceover of a storyteller. The burst of laughter represents peak loudness, a brief moment where the sound spikes to its highest intensity. In contrast, the storyteller's consistent voice represents constant loudness.

So we know that loudnes is more complicated than just a volume. And that it can be measured in short bursts (peak loudness) and over time (constant loudness). But how is it measured? 

How is loudness measured?

Think of loudness like a volume scale. On this scale:

This scale is measured in units called decibels (dB). Just like we use miles or meters to measure distance, we use decibels to measure sound volume. You can learn more about this scale and see examples for how loud various common sounds are here.

Why is this so important? Well, imagine watching a movie where the dialogue is so quiet you can't hear it, but the action scenes are deafeningly loud. To avoid such inconsistencies, industries like TV, movies, and music use this scale to ensure we get a clear and comfortable listening experience.

This also helps TV stations make the ads sound louder than the main content like the TV show or news. Ever noticed that before? 

When we talk about podcasting, music production, mixing, and mastering, there are three main methods of measuring loudness:

1. LUFS (Loudness Units Full Scale) [Most important for podcasters] 

LUFS is the most accurate way to measure overall loudness. It uses a special formula that mirrors how our ears respond to different volumes and tones.

Major music platforms, like Spotify and YouTube, use LUFS to ensure songs play at a consistent volume. It's the industry standard for maintaining volume consistency across tracks.

2. Peak Loudness method

The Peak Loudness Method measures the loudest moments of a sound instantly. It's great for detecting sudden volume spikes in audio. You'll often see peak meters in music software and on audio equipment. 

While useful, it doesn't give the best overall picture of loudness. Averaging these peaks provides a clearer idea.

3. RMS (Root Mean Square) method

The RMS Method calculates the average loudness of sound over a short duration. This method is closer to how our ears naturally perceive loudness. It's a favorite tool for music professionals during the mixing and mastering process.

RMS is also used to determine the volume output of studio speakers.

How to set the proper loudness for your podcast episode

One things thats important to understand about audio normalization is that streaming platforms will automatically normalize your audio whether you do or not. For example, if you upload a podcast at -4 LUFS to Spotify and think it’s going to sound WAY louder than everyone else’s file, think again. 

Spotify will automatically normalize your audio to -14 LUFS. This goes for almost all major platforms now, including Apple Podcasts, YouTube, Amazon Music, and many others. 

Before normalization became a thing, people used to think that a song sounded better if it was louder. So, a lot of audio engineers wanted to make mixes really loud to make the track stand out. But now, like it or not, things have changed, and normalization is here to stay.   

Here’s how you can set the proper loudness of your podcast:

1. Setting podcast loudness manually 

You can use a digital audio workstation (DAW) like Pro Tools, GarageBand, or Audacity to adjust the loudness of your podcast manually to ensure the best sound quality for listeners, while keeping the loudness consistent.

The steps would be a bit different for each DAW, but at a high level the process would look like this: 

1. Open your DAW. 

2. Import your audio file(s). 

3. When recording, set your microphone level so that the loudest moments are around -12 dB to ensure a good signal-to-noise ratio. 

4. Make sure your tracks all have a smooth and consistent volume by normalizing them with a pluggin, manually adjusting them, or with compression. 

5. Use 'EQ' to balance audio frequencies for clarity.

6. Use a loudness meter to analyze your audio in LUFS and adjust the volume of individual tracks, clip gain, and any effects like compressors until you achieve -16 LUFS (Apple’s standard). We recommend the free YouLean Loudness Meter to get started.  

7. Save the changes and export the audio.

8. Listen on various devices to ensure consistent quality.

Going back to step 6 in this list, there are many other loudness plugsin you could check out if you don’t want to use the YouLean Loudness Meter. 

The best loudness meter plugins for DAWs

These third-party plugins integrate with all the major DAWs and help you manually figure out if your podcast audio is set to the proper loudness (in LUFS). 

1. YouLean Loudness Meter

The YouLean Loudness Meter boasts a clean and accurate interface. It can quickly scan and display information about peaks, the dynamic range, and LUFS measurements.

2. WLM Plus Loudness Meter

The WLM Plus Loudness Meter is an affordable option for those on a budget. Its interface is straightforward, allowing for easy volume readings at a glance.

3. FabFilter Pro-L

The FabFilter Pro-L is known for adjusting loudness without compromising on clarity.

It has a special display that shows audio levels as they change in real-time and indicates how much the loudest parts were turned down.

4. Insight 2 by iZotope

Insight 2 is a comprehensive metering and audio analysis plugin developed by iZotope. It's designed to provide visual feedback on the sound quality and loudness of audio content, making it an invaluable tool for post-production and mixing engineers.

As you can see, manually adjusting loudness is a pain. But thankfully there’s an easier way. Let’s talk about how to do this automatically now… 

2. Automatically set podcast’s loudness to -16 LUFS with Resound

If you're feeling overwhelmed by all this podcast loudness stuff, don't worry! There's actually an easier way to get perfect volume levels for your podcast, even if you're not tech-savvy at all. 

You can use AI to adjust the loudness of your podcast! Resound makes it as easy as a few clicks to adjust the loudness of your audio using AI mixing and mastering. 

How does it work? Just create a free Resound account, upload your files, let Resound process, click “Enhance” and your audio will automatically be set to the proper loudness levels of -16 LUFS (recommended by Apple Podcasts). It will even normalize your tracks so that all the speakers have a similar loudness, equalize, remove background noise, and more. 

Final Thoughts

Understanding LUFS is important, but loudness is ultimately only one piece of the puzzle to making a great podcast. Try Resound to automatically edit, mix, and master your podcast today. 

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Resound.fm Team
Resound's team is building the future of podcast editing: An AI podcast editing app for creators. Here at Resound we're writing about the creative process to help content creators thrive. Picture is Ernst Chladni, the inspiration for our brand. Hear his story at resound.fm/about
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