Explore the incredible visual tools podcast editors use to produce high-quality podcasts.
How does your audio editor see your podcast? That's probably not a question that comes to mind very often, if ever. But it's a fascinating question nonetheless. Audio professionals rely heavily on their well-trained ears, of course, but we also have some incredible visual tools at our disposal that are truly captivating. The world of audio engineering that I surround myself in is a mystery to most, which is why I'm excited to showcase some of the ways in which we see sound.
This article contains a basic overview of the visual tools I, and many other audio professionals use while editing podcasts. If you wish to learn more about a specific visual tool, check out the Resources and Additional Learning Materials at the end of this article. You can also reach out to me directly via the comment section or by filling out the contact form found on The Podcast Solution contact page.
Waveforms
The first step when starting any audio project is to import the audio files into a digital audio workstation or DAW. Pro Tools is the DAW I use for podcast editing. Pro Tools automatically generates a graph for each file imported into the session that displays the amplitude/volume of the audio over time. These graphs are called waveforms. Waveforms provide a great deal of information to the trained eye. I can often tell what the quality of the recording is going to be just from viewing the waveform.
The waveform image above the title of this section is ideally how each audio file should look. Without listening I can tell there's not a great deal of excess noise, pops, or clicks. Every transient, or audio peak, is fully present. The audio isn't clipped, so there shouldn't be any unwanted digital distortion. When I receive audio files for a podcast that look similar to the above image, I know it's going to be a good day.
Numerical Metering
(Peak Meter - RMS Meter - Loudness Meter)
Numerical meters are used throughout every stage of podcast production. They assist with setting proper levels during recording, they're used to balance the levels of different voices and music in an episode, and they're an important tool for checking the final audio levels during the mastering stage.
There are many different forms of audio meters. The main types of metering used during podcast production are peak, RMS, and loudness meters. Peak and RMS meters are digital metering tools that are typically combined together like in the image below. A peak meter will display the loudest value of an audio signal. An RMS meter measures the average level of an audio signal.
Quick Note About the Colors:
Digital meters typically display green, yellow, and red colors to help us quickly determine the level of the audio signal without having to focus too much on the numbers. Just to keep things simple - green is good, yellow is good, but red is bad. Red indicates that your signal has exceeded the 0.0 dB digital limit or "ceiling". Audio that surpasses that limit will likely introduce digital distortion.
Pro Tip:
When using a digital meter to set the gain level on your podcast microphone, try to keep the loudest peaks below -6 dB and your average level between -24 and -18 dB.
Loudness meters are used during the mastering stage to ensure each episode is exported at a proper level. The most important value we need to pay attention to here is the integrated LUFS value. LUFS stands for loudness units relative to full scale, which is just a method of measuring the overall loudness of a digital audio file.
How loud should a podcast be?
The current loudness standard for most podcast streaming platforms, including Apple Podcasts, is -16 dB integrated LUFS and a -1 dB true peak.
Spectrogram
Podcasts that are recorded outside of a professional recording studio are likely to contain background noises that can be distracting for your listeners. Fortunately, we're able to remove or at least reduce many of those unwanted sounds. There are limits to what can be removed, of course. And sometimes removing a noise problem can sound worse than leaving it in. Sounds like a car honking or the hum of an air conditioner are common problems that can be dealt with without too much trouble.
In order to combat any noise problems, we need a detailed view of the audio file. That's where the spectrogram comes in. The layout of a spectrogram allows for unwanted background noises to be visually spotted within the frequency spectrum of the audio file. Then, in most cases, the background sounds can be isolated and reduced. Incredible right?
I use an audio repair program called iZotope RX. The spectrogram view in this program can be customized to show extreme detail. Take a look at the below image of a vocal phrase I imported into iZotope RX. Time is displayed on the x-axis, frequency is displayed on the y-axis, and amplitude/volume is displayed via the colors. The color scale is located at the far right of the below image for reference. Basically, the louder a frequency, the brighter it will be displayed.
I've highlighted a few areas of this vocal phrase to give you a better understanding of what it is we're looking at. The sound in box "1" is a breath taken before the phrase begins. Box "2" contains the word "life". The fuzzy/static area highlighted in circle "3" is the background noise captured in the recording.
There's a great article on iZotope's website about spectrograms and the RX program. Click HERE to check it out.
Frequency Analyzer
Once the editing of an episode is complete, we move on to the mixing stage. One of the best visual tools to use during this stage is a frequency analyzer. This visual tool graphs the intensity of all frequencies of an audio file in real time. This tool becomes extremely beneficial while using an EQ to boost or cut frequencies.
Looking at the below image, you'll see that a 20 Hz - 20 kHz frequency range is expanded across the x-axis and the volume level of each frequency is graphed on the y-axis. The graph can be customized to display precise detail like the below image, or it can be set up to display broad intervals such as the 1/3 octave chart also pictured below.
Analyzer setup in 1/3 octave intervals
Frequency Analyzer in action (no sound)
Final Thoughts:
I hope you found these forms of sound visualization as fascinating as I do. It's truly incredible how advanced some of these tools have become. Learning about spectrograms was a huge game changer for me and is by far my favorite way to see sound.
If you learned something new or found an idea particularly helpful, please like and share this post. Let me know in the comments below what visual tool you found the most interesting.
Don't forget to subscribe to this blog to receive updates on future articles.
- Sterling Skye
Visual Tools I Use:
Insight - iZotope: https://www.izotope.com/en/products/insight
Resources and Additional Learning Materials:
Hoffman, Charles. “6 Mastering Meters You Need to Learn How to Use.” Black Ghost Audio, 27 Jan. 2019, https://www.blackghostaudio.com/blog/6-mastering-meters-you-need-to-learn-how-to-use.
“Understanding Spectrograms.” iZotope, 3 Apr. 2020, https://www.izotope.com/en/learn/understanding-spectrograms.html.
“Understanding Waveforms.” SWPhonetics, https://swphonetics.com/praat/tutorials/understanding-waveforms/.
“What Are Waveforms And How Do They Work?” SoundBridge, 17 Apr. 2019, https://soundbridge.io/what-are-waveforms-how-they-work/.
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