The important differences between MP3 and WAV files that every podcaster needs to know.
The quality of your podcast could be doomed from the start if you're recording and/or sending the wrong audio file formats to your editor. Chances are, you didn't even know that there are different audio file formats like MP3, WAV, or M4A. Or, maybe you weren't aware that there's differences between them. That's what some of my clients have told me.
What is an MP3 file? Why are WAV files much larger than MP3s? Both file formats sound the same to me, is there really a difference? These are just a few examples of what I've been asked regarding this topic and I'm going to answer them all here. But before that, let's answer the leading question first...
What audio file format should I send for editing?
If producing your show at the highest quality possible is important to you, you should be recording and sending WAV files to your editor.
Why send WAV files rather than MP3s? There is a significant difference between these file types that you need to be aware of that makes this question simple to answer. But first, to truly understand the differences I'm about to explain, we need to quickly review some foundational terms related to digital audio. I'll try to keep things simple here, but if you want to skip the nerdy stuff, jump to my summary here. If you'd like further explanations or wish to learn more, check out the resources and additional learning materials at the end of this article.
Technical Terms
A Digital Audio File is a collection of binary data created from a series of snapshot measurements (samples) of a sound wave's frequencies and amplitude over time. The amount of data captured in a single snapshot is typically determined by sample rate and bit depth.
Sample Rate determines the amount of times a sound is sampled per second. This will determine the range of frequencies captured, measured in kilohertz (kHz).
Bit Depth sets the amplitude scale of an audio file. Higher bit depths offer more dynamic range and a more accurate representation of the sound. It's also thought of as the resolution of each snapshot.
Bit Rate is the number of bits processed or transmitted per second, often measured in kilobits per second (kbps). The higher the bit rate, the higher the quality.
Uncompressed in digital audio refers to an unaltered copy or representation of a sound file.
Compressed in digital audio refers to a reduction of information in a sound file in order to reduce file size.
Lossless is a form of compression that involves no loss of information.
Lossy is a form of compression that permanently discards information in order to further reduce file size.
Now that we've covered a few of the terms used to classify and describe digital audio files, let's explore the differences between the WAV and MP3 formats that you should be aware of as a podcaster.
MP3 (MPEG-1 Audio Layer III)
The MP3 file is by far the most well-known form of digital audio. After it's initial release in 1993, the MP3 file format quickly became a hit with it's ability to reduce file sizes by over 75% compared to CD-quality digital audio. MP3 compression works by reducing frequencies that extend beyond the hearing capabilities of humans. This data is permanently removed from the file during the MP3 compression process.
This file type is considered low quality compared to other digital audio formats. MP3 files are commonly described as sounding dull or flat. This is because the frequencies most affected by the compression process are the higher frequencies that make up that brightness and presence in a recording. Lower frequencies are also degraded, but it's not as easy to hear.
Main Uses:
Streaming & Downloading
Sharing (Email / Text)
Technical Details:
Filename Extension: .mp3
Compressed - Lossy
Typical Bit Rate: 96 - 320 kbps
Typical Sample Rate: 44.1 kHz / 48 kHz
WAV (Waveform Audio File Format)
Developed by IBM and Microsoft, the WAV file was designed to accurately represent analog audio in a digital format. This is done by using pulse-code modulation (PCM) to capture samples of an analog signal at uniform intervals.
Since this file type is an uncompressed, high-quality representation of analog audio signals, the file sizes can be extremely large. This makes it less ideal for streaming and sharing purposes. WAV files are the standard digital audio format used by audio professionals.
Main Uses:
High Resolution Recording
Editing, Mixing, & Mastering
High Resolution Downloads
Technical Details:
Filename Extension: .wav
Uncompressed - Lossless
Typical Bit Depth: 16-bit / 24-bit / 32-bit
Typical Sample Rate: 44.1 - 192 kHz
A few other audio file formats you may encounter:
M4A (MPEG-4 Audio): An M4A file is the audio only component of an MP4 file, which is a multimedia container that stores video and audio information. It was designed to be the successor to MP3 with an increase in quality while maintaining a small file size.
AIFF (Audio Interchange File Format): Similar to the WAV file, AIFF files are lossless and uncompressed. This format was developed by Apple in response to IBM's and Microsoft's WAV file. Other than the different filename extension, the two file types are identical.
Why WAV files are superior for recording and editing:
The main reason why WAV files are superior for editing is due to the fact that they as lossless files. It's the full, unaltered representation of your episode. An MP3 file is a reduced, lower quality rendition of your recording.
Editing with WAV files is even more important if your podcast incorporates music or sound effects throughout the show. If your voice is an MP3 file and the music is WAV, your voice will sound extremely dull compared to the music.
MP3s are great for sharing and streaming, but not the best for editing. Converting your episode to an MP3 file should be performed after the editing is complete by a high performance converter.
PRO TIP: For high-quality recording, set your audio interface and/or recording software to record WAV files at 48 kHz with a 24-bit depth.
Final Thoughts:
It's true, the file that's uploaded to your distribution platform is likely in MP3 format, but that doesn't mean that's the file format you should be sending to your editor. It will take some extra time to upload and send WAV files, but it's well worth it. The audio quality and file size can always be reduced later on in the production process if needed. Sound removed in an MP3 file can never be recovered, so best leave that step for your editor.
Is there a podcaster you know that could benefit from this article? Share this post with them before you go!
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- Sterling Skye
Resources and Additional Learning Materials:
Brown, Griffin. “Digital Audio Basics: Sample Rate and Bit Depth.” IZotope, 15 July 2019, www.izotope.com/en/learn/digital-audio-basics-sample-rate-and-bit-depth.html.
“MP3.” Wikipedia, Wikimedia Foundation, https://en.wikipedia.org/wiki/MP3.
“WAV.” Wikipedia, Wikimedia Foundation, https://en.wikipedia.org/wiki/WAV.
“MPEG-4 Part 14.” Wikipedia, Wikimedia Foundation, https://en.wikipedia.org/wiki/MPEG-4_Part_14#Filename_extensions.
“General Knowledge of M4A Format.” Apowersoft, 9 July 2020, www.apowersoft.com/what-is-m4a-format.