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Bit Rate

Last updated: May 23, 2022

Bit rate largely determines how compressed your audio is and how large the file size is in megabytes. Codecs such as MP3 are known as lossy compression (rather than lossless). This means there is a trade-off between quality and file size. You can make an audio file really small by exporting it at a really low bit rate (e.g. 8kbps) but you’ll be throwing away most of the data and will be barely able to make out any speech — it will sound really muffled or like a bad radio and filled with digital glitches.

Headphones and digital audio equipment has generally improved over the past few decades and people have become accustomed to higher levels of quality even when out and about. At the same time internet speeds have increased to the point where most people can download a high bitrate podcast in a matter of seconds, though this varies across the world. The space an audio file takes up on the listener’s phone is also something to consider but the storage on recent devices has largely made this a non-issue.

We recommend a bit rate of 128 kbps to 256 kbps. 256kbps is generally considered the minimum you’d want to rip a music CD at. If your podcast is mainly speech then 128kbps is probably fine but this lower end is not so common as it was. As a side note, the main audiobook standards recommend 192kbps at a constant bit rate.

Whilst you’re here…

Audio Audit is an automatic benchmarking and proofing tool which checks the quality of your podcast MP3 files, giving you peace of mind before you publish.

It checks things like loudness, silences, restarted sentences, encoding, swearing and metadata.

Learn more ⇢Screenshot of an Audio Audit report

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