WAV vs. MP3 Files: A Guide to Audio File Formats

Digital audio files are essentially computer code that communicates to a digital device (a computer, phone, or tablet) how to produce analog audio through speakers or headphones. Digital audio files are created by converting analog audio (sound waves) into digital files.

The format of a digital audio file affects playback quality and your ability to use the file on a digital device. Higher-quality digital audio files sound great, but they can take up a lot of hard drive space. This is because they contain a tremendous amount of information about the analog audio signal that the computer is to produce. Such files have a very high bitrate, and they can produce CD-quality sound. Other, lower-quality audio files have a low bitrate and take up less hard drive space.

Some compressed and uncompressed audio files can replicate the sounds of the original master tapes used to make a recording. Audiophiles call such formats "lossless" because they lose none of the audio fidelity of the original recording. Lossless audio formats include AIFF (audio interchange file format), WAV, and FLAC (free lossless audio codec). These files can be somewhat impractical, mostly due to their massive file size.

Most leading audio software favors the mp3 and AAC file formats. These music files compress the original audio and are known as “lossy” formats. The loss in quality is counterbalanced by their very reasonable file sizes.

A WAV file is a lossless audio format that does not compress the original analog audio recording from which it is derived. Microsoft and IBM pioneered the Waveform audio file format, and it is now widely used by digital music companies around the world. As a lossless format, WAV files offer a very high sample rate and bit depth, which permits them to include all the frequencies heard by the human ear.

A WAV file encoder uses a technique called pulse code modulation (PCM), which samples analog sound waves at regular intervals. (Some computer systems call this linear pulse code modulation, or LPCM.) The PCM encoder converts audio data into digital data with varying degrees of detail. For a CD-quality file, the PCM is at 44.1kHz and 16 bits. However, most audiophiles prefer 48-kHz and 24-bit stereo sampling, which allows even more high frequencies and low frequencies to enter the mix. This sampling rate exceeds the audio quality of CDs.

Use the WAV file format when you need the highest quality audio. The most common application for this would be the recording of original audio. If you're laying down tracks for your band in the studio, or if you're recording a podcast, save each track as a WAV file for maximum audio fidelity.

An mp3 is the most popular type of lossy audio—that is a digital audio file that has been compressed to a manageable size for storage, streaming, and downloads. Smartphones and tablets play mp3 files. The mp3 compression algorithm does result in a loss of quality compared to the original analog audio files. Yet for many listeners, this quality loss is all but imperceptible.

For most human ears, the most noticeable downside to mp3 versions of songs is a weakened bass response. This is particularly true of mp3 files coded at very low bitrates, such as 128 kbps. To counteract this, seek out mp3s that are only lightly compressed, such as 256 kpbs or, even better, 320 kbps. You can also use your audio player's equalizer to boost frequencies that may be lost during mp3 compression.

For most casual listening, the mp3 format is more practical than the WAV format since the files are compact and easy to stream. If you download mp3s, they won't take up too much space on your phone or computer. And unless you're using top-of-the-line headphones or speakers with a high-powered preamp, you may be unable to hear the difference between a lossless WAV file and a lightly compressed mp3 file at 320kbps.

Avoid using mp3 files when recording and instead use the highest-fidelity files your computer system can handle. You can always compress the files later on, but you can't recapture full audio fidelity from a compressed mp3.

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