Today I want to answer a question I received about determining your target loudness and encoding settings. I want to thank Sergey for the question. He’s asked some good questions and I appreciate it. firstname.lastname@example.org.
How to determine what your target loudness and encoding settings should be
The most important question regards the purpose, format, and audience of the particular podcast in question.
Dynamic range, loudness, and the purpose of your podcast
A podcast created for the purpose of sharing poetry is going to be different than a podcast created for delivering political debate show. Poetry is read, often quietly, and with very intentional inflection, and dynamic range. You don’t want to lose any of that in the processing, and encoding of the file. On the other hand, a political debate show will have less dynamic range. And it’s not nearly as important to capture the nuances of the inflection of people’s voices. As a result there’s no need to process such a podcast in a way that preserves the dynamic range.
Encoding, loudness, and the format of your podcast
In the same way, the format of a show will play a role in determining the loudness, format, bit rate, etc.
If I’m producing an audio narration like a documentary I’m going to shoot for a loudness between -20, and -15db, and a higher bit-rate than most other podcasters would – say 160kbps for a stereo recording (and I would use a stereo recording). And I provide step-by-step instructions as to how to accomplish this using my suggested software on Mac, and Windows – or using Auphonic after you’re done editing. I would shoot for a louder output, and a lower bit-rate if I were producing a typical talk show.
If I play music in my show, I definitely want a higher quality encoding for my vocals. Otherwise the music would sound bad, and then my vocals would sound even worse next to the music which was professionally engineered. I would encode at at lest 160k Joint Stereo.
Other thoughts related to encoding and loudness
Now, I wouldn’t change my encoding, and target loudness between episodes of the same podcast show. But my podcasts do have different encoding, and loudness.
Now here are some tips for encoding:
- Don’t use VBR
- Only output into stereo if you’re really serious about wanting stereo, or you play lots of music in your podcast, or you do interviews and really want to pan the voices left to right a little bit.
- Go ahead and export at a higher quality than you’re tempted to. File size isn’t as important as it used to be. Quality is more important, and it will separate your podcast from others.
Something else to keep in mind is that if your podcast is very long (over an hour) you should consider using a lower bitrate encoding, or using mono. Because it’s possible that your file size may be too big. And it may discourage people from downloading your podcast if the file takes too long to download.
LAME vs Fraunhofer mp3 encoding
Another important debate in the podcast world has to do with which encoding algorithm to use. The two most popular mp3 codecs are LAME and Fraunhofer (the names aren’t important). All you need to know is that Fraunhofer is the better one, and I believe it’s demonstrably better. If you’re serious about quality us Fraunhofer. I show exactly how to do this in my course, and I believe it’s important.
Loudness standards for podcasting
I should mention that the podcast standard for loudness is around -15db LUFS. And, again, I show how to do this using my preferred software in my course, but you can also do it using Auphonic – which I also talk about in my course, and I will cover at some point here on this show. In short Auphonic is an automatic audio post production leveler and normalizer service, with optional software. It does a great job, but you don’t need to pay for it if you follow my blueprint for podcasting, because it’s redundant.
Sample rate and bitrate when recording podcasts
There’s one more think I want to touch on, and that’s recoding settings. I usually record at 16bit, 44.1k into .wav, or .aif. However, sometimes I record using 24bit, 48k – and sometimes, for fun, 96khz at 24bit. There’s a lot of debate over this technical aspect of podcasting, and I believe that recording in higher bitrates and sample rates do produce higher quality podcasts even when you encode them into mp3 at lower bitrates and sample rates. I won’t get into the technical reasons, but it does help lower your noise floor and give you a slightly higher quality sound. It’s not worth it in most cases – especially int he case of a typical talk show – but in some cases higher quality is absolutely worth it.
90% of the time 16bit, 44.1khz is just fine for both recording.
Podcast Terms Segment
But before I answer his question let’s take a look at the podcast glossary and and define a couple terms
- Encoding: Refers to the process a computer uses when saving a file recorded in one format into another format. We will be saving AIFF/Wave files into Mp3 files used for podcasts.
- ID3 Tags: These tags contain information regarding an audio file. Information like title, artist’s name, etc. They’re embedded in the audio file itself.
- VBR (Variable Bit Rate): An encoding option for audio files which tries to minimize file size by encoding to a sliding quality scale instead of a fixed bitrate. ACX does not accept VBR files.
- WAV: The most common uncompressed audio format. You should record, edit, and master your audio as WAV files until you are ready to convert to MP3.
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