What Bit Rate Should I Export My Podcast Episode As?
The results of the study didn’t surprise me: I discovered a few years ago that 64–128kbps is the ideal bit rate for podcasts (small file size without a noticeable loss in audio quality for an average listener).
For the past few years, my advice for podcasters who ask me about bit rates and mono vs stereo files has been:
- 96kbps mono is great for shows that are mostly just people talking (talk shows, interviews, etc)
- 128kbps stereo is great if you have stereo music or a lot of sound effects (think Radiolab or Serial)
Of course, you might be wondering, “Bit rates? Mono, stereo, why does it matter?”
It matters because most of us want our podcast episodes to sound good, and many people believe that a higher bit rate means better sound quality, or a lower bit rate means lower sound quality. While this is technically true, the bit rate doesn’t have as much of an impact on overall sound quality as what happens in the recording and post-production (mixing and mastering) stages.
The most important thing to remember is that great sound quality starts with the recording stage.
Recording an uncompressed audio file (.aiff or .wav) with a great mic in a quiet room with proper input gain and mic technique will yield a better sounding audio file than recording with a super cheap microphone in a noisy room (especially if you’re far away from the mic or if your input gain levels aren’t set correctly).
If you start with an uncompressed audio file that sounds great, you can export it as a MP3 file at a lower bit rate (96 or 64kbps, for example) without losing much audio quality.
There may be a few audiophiles in your audience that can hear the slight difference between 96kbps and 128kbps, but your average listener won’t hear the difference, and if they do, it won’t degrade the experience enough to bother them.
What do the podcast professionals do?
Radiolab is a podcast that has consistently sounded great over the years, but it’s not because their MP3 files are encoded at a high bit rate like 320kbps, it’s because the producers are experienced audio engineers who know how record and mix audio well.
They start with high quality raw audio, so the MP3 file they deliver to listeners sounds better than your average, untrained, independent podcast producer’s show.
The results of James’ study proves this point. Take a look at these popular shows that export 96kbps MP3 files:
- Dan Carlin’s Hardcore History
- Freakonomics Radio
- Happier with Gretchen Ruben
- Slow Burn
Those are some pretty popular shows, but take a look at the list of shows that use 128kbps audio files:
- 99% Invisible
- Good Life Project
- Masters of Scale with Reid Hoffman
- MSNBC Rachel Maddox
- StarTalk Radio
- The Tim Farris Podcast
- Welcome to Night Vale
As you can see, some of the most popular podcasts in the world are delivering 96 and 128kbps MP3 files to their listeners.
What about Lore?
I’m going to highlight an exception to make one final point, and that is Aaron Mahnke’s Lore podcast. Lore’s episode files are encoded at 256kbps, almost double the apparent average of 128kbps.
Why? I believe it’s because Lore is intended to be an high quality audio experience. Many podcasts are just conversations between humans (without music playing in the background), but that doesn’t mean they aren’t valuable or enjoyable to listen to.
Lore episodes contain carefully crafted narratives with beautiful music playing in the background, and I’m sure Aaron cares immensely about audio quality. He’s made a decision to export his podcast episodes at a higher bit rate, trading a smaller file size for slightly higher audio quality. This is his choice to make and I don’t think there’s anything wrong with it.
One of the best things about podcasting is how much freedom you have: If you want to export your podcast episode at a higher bit rate, you’re free to do so, but it’s important to understand that while a higher bit rate won’t magically make your podcast sound better, a higher bit rate does mean a bigger file size which can be a problem for listeners with capped data plans or limited access to the internet.
I said back in 2015 after a few years of listening to MP3s (podcasts and music files ranging from 32kbps mono to 320kbps stereo) that 96kbps mono is the ideal balance between audio quality and file size for podcasts without music, and 128bkps stereo is great for podcasts with music, but in the end, you’re free to export at whatever bit rate you prefer.
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