MP3 vs. WAV: What's the Difference?

File formats and codecs can be the most confusing aspect of post-production. When exporting a media project, you are often presented with various export options, each impacting your footage differently.

For example, if you choose one format, the video file will become too large, or the quality will be lost if you select another. Audio formats may seem more straightforward than video, but they can still be confusing.

Those are quite a few formats to choose from! 

However, at a fundamental level, we can focus on two globally used formats. WAV and MP3. Understanding the difference can help you choose the right one for your project. 

MP3 vs WAV: What’s the difference in audio quality?

Ok, let’s say you’ve got a collection of sound effects on your computer (and if you don’t, now’s a great time to start building one), you’ve probably noticed a mix of .WAV and .MP3 files sitting within the folder.

Or, if you’re downloading from a sound effects library, you’ve likely seen an option like this to choose between formats:

So, which is the right one to use? 

Well, audio is typically categorized into two distinct categories: compressed and uncompressed.

A good analogy for understanding uncompressed versus compressed audio is comparing a RAW photo from a digital camera, and a photo downloaded from online. 

With an uncompressed RAW camera photo, you have access to a wealth of hidden data not immediately visible. This allows you to recover detail from shadows, reduce blown-out highlights, and adjust colors more freely without introducing artifacts into the image.

Image via Lewis McGregor

However, while you could download a JPEG version of that very same image, that RAW information no longer exists within this format. Likewise, when you upload a picture online, the service compresses that picture to reduce file size and ensure faster load speeds. In turn, this sacrifices some detail.

How many times has this image been uploaded and saved? Quite a few times. 

With that, we can see that WAV is like an uncompressed RAW photo straight from the camera. It’s an uncompressed audio format, meaning every bit of data is preserved without alterations. Even silent portions are preserved in a WAV file, meaning no data is discarded.

MP3, on the other hand, is a compressed file format. The software you're working with will use data algorithms to compress the file into a smaller size without drastically altering the quality. 

While it's often tricky to audibly hear the difference between the two, there is a numerical difference in the value held between both compressed and uncompressed files. 

For example, this is a WAV file for a crowd cheering at a baseball game. We can see both the waveform and the spectral frequency display. 

This is the same audio clip, but the MP3 version. 

Notice anything different? On first glance, it’s not so obvious. However, let’s focus more on the spectral frequency display for each file type.

If you look closely at the frequency peak (top of the graph), we can see that the MP3 file format loses data value, and that area is empty. This absence indicates where compression has removed audio information, typically high-frequency details, to reduce file size. Perhaps not the most significant loss for someone making a quick YouTube video, but for audio specialists, that could be make or break.

More on WAV

WAV, short for Waveform Audio File Format, is a widely used audio file type. Whether to call it WAV or WAVE is mildly debated, maybe not on the level of JIF vs. GIF, but you’ll hear people say it both ways.

A WAV file ensures that audio data remains untouched from recording to post-production software. That’s why sound designers, music producers, and audio editors rely heavily on this format. It retains all of the high-quality characteristics that this audio format carries. 

Again, if we play a WAV file or an MP3 file of the same audio track through your home television unit, mobile phone, or computer speakers, you may not hear the difference immediately. But the moment we bring it into a mixing studio, a theater setup, or even a home surround sound, you will start hearing audible differences.

It’s like watching a 4K trailer on your phone versus a 56-inch TV. While the difference might be negligible on a small screen, it becomes noticeable in a high-end setup.

If you're field recording, for example, outdoor ambience or indoor sound effects, preserving every detail in that recording is essential, as it's the most accurate representation of the sound heard on location without losing quality.

The same goes for music producers in the mixing and mastering stages; they ideally like to work with stems in WAV formats. This ensures that the audio is at a lower risk of decreasing quality in the editing stages due to the flexibility of WAV files. 

Image via Unsplash 

However, the downside to using the WAV file format is that it is much larger due to the amount of data it carries. As a result, a handful of lengthy ambient field recordings can soon eat up your storage space compared to the compressed MP3 file format. 

Take the downloadable SFX above as an example: a 21-second audio clip of a spaceship flying away is just 0.8 MB, which is pretty reasonable for a short sound effect. But the WAV version comes in at 5.3 MB. 6.6x the size!

For comparison, the 2-minute-29-second song, "Communication Breakdown" by the legendary rock band, Led Zeppelin, is only 4.89 MB as an MP3. So if your SFX and audio recordings are all in WAV format, you’re not just going to need an extra folder—you might need an extra hard drive.

More on MP3

So, let's have a look at MP3s. MP3, also known as MPEG-1 Layer 3, is a compressed file format for digital audio. This format was specifically created to reduce file sizes in the compression stages while keeping the original representation of the sound.  

Some technologies arrive too early; they are helpful in theory, but not quite right for their time. MP3, however, came at precisely the right moment. Released in 1991, the format took off alongside the rise of digital music and the internet throughout the mid-to-late '90s. Its small file size and decent quality made it the go-to format. As a result, we saw a massive boom in online music distribution, although not always through legal means. 

The use of ID3 tags also helped its online popularity. ID3 tags are a form of metadata that allows users to add details to the file, such as the artist, the title, the genre, the disc track, etc., which allows for easier file organization.

“Move over Walkman, the MP3 player is here now.” - Some tech executive in the 1990s. Probably. 

Using MP3 is advantageous because the file sizes are much more manageable. In addition, the compression works by eliminating inaudible audio in the data, as specific frequencies are impossible for the human ear to distinguish. Or in a more technical sense, “the lossy compression algorithm takes advantage of a perceptual limitation of human hearing called auditory masking.” 

Now, it's not as if we're diminishing the actual quality of the sound. Again, it's similar to watching a 4K video trailer on YouTube. The quality is still going to be great, it's going to be watchable, and the clarity is going to be fine, but it's not the same as watching that 4K trailer on your desktop player before it has been uploaded to YouTube and compressed by their system.

However, MP3's disadvantage is that we're not getting that initial 100% recording, specifically in the dynamic range, so this isn't ideal for editors who need high fidelity in their audio files. 

Which format should you choose? 

So, which format should you choose? The larger but more faithful WAV files or the more streamlined and shareable MP3s?

Ultimately, it all comes down to where your project is being distributed. If you are an audio editor or sound engineer who needs to edit audio files for a film project, then using WAV files should be your first choice. They have a much more dynamic range, as every bit of data is preserved. Hence, when the audio is edited, it avoids the risk of noticeable audio quality.

But if you're sharing a video for social media or uploading a quick bit of content to YouTube, and given that 3 out of 5 YouTube views are viewed through a mobile device, additional storage space, processing, and so forth might not be that important. In this instance, an MP3 is more than adequate.

However, it is worth noting that the institute that developed the MP3 has officially discontinued supporting the format. They now state that there are more advantageous compression formats out there, such as AAC, that can compress the file even further while retaining more of the audio's quality.

However, because MP3 has been a staple of audio formatting for so many decades, the switch has been a slow one at best.