Audio Encoding Guidance
Once you've got your first episode recorded and edited it's time to get it into a format that your audience can listen to. This is the last step in the editing process: exporting your finished audio file from your Digital Audio Workstation (DAW) like Adobe Audition or Audacity.
Castos believes that the audio that you upload to our platform should be the same format and bitrate that your audience listens to. We do not perform any post-processing on your files because we know that you go to extraordinary lengths to get your episodes sounding Just Right in recording and post-production.
That being said we do believe there is a Right Way to prepare your audio files to be uploaded to the Castos platform.
Within the Castos platform you can publish audio files either as .mp3 or .m4a file format, however .wav files are not supported.
File Export Settings
The export settings that we recommend for all of your audio files are:
- File Format: MP3
- Bitrate: 128 kbps
- Mono or Stereo: Mono is usually sufficient if it's just spoken word, but if you have sound effects then Stereo is a nice touch.
The bitrate that you export your files at is a balance between creating a really high fidelity file with a file size that's reasonable for your audience to download or stream. The highest fidelity file may have a slight increase in quality of sound, but will take too long for your audience to download. If the file is smaller it will download more quickly but will sacrifice a bit of audio quality along the way. The 128 kbps bitrate is a nice compromise between those two concerns.
Here's just a few other additional settings you may find in your audio editing software:
- Sample Rate: 44.1 kHz
- Bit Depth: 32-bit float or 24-bit
- mp3 Type: Constant Bit Rate (CBR)
What about loudness?
If you've ever switched from one podcast to another and noticed that one was waaaaay louder than the next then you've encountered inconsistent loudness settings. The loudness is just the volume at which your files are exported, and should be benchmarked against these industry standards:
- Mono: -19 LUFS (this is the same perceived loudness as -16 LUFS for stereo)
- Stereo: -16 LUFS
Following the guidance above will give your podcast a high quality sound that your listeners will appreciate and keep them coming back.