File Formats, Audio Compression, and Why it Matters

Ever since the invention of the phonograph, engineers have been searching for the highest quality, robust, convenient, and easily reproducible solutions for recording, storing, and reproducing audio. From wax cylinders and vinyl records to the online streaming services of today, the way music is distributed and consumed has evolved rapidly over the last century and a half. Though the most die-hard audiophiles may lament the passing of the truly analog era, the robustness and convenience of digital music files makes it impossible to argue that they will be the primary medium for music consumption for the foreseeable future.


So what file type should you be listening to? And why do so many different types exist? Let’s go over a few of the most common audio file types and their intended purpose.


Uncompressed Audio

What it is:

Uncompressed audio is simply raw, uncompressed audio data. Common uncompressed formats are WAV and AIFF. Even completely uncompressed audio can differ in quality, depending on sample rate (number of samples/second) and bit depth (number of bits used per sample). Standard CD quality is 16 bit 44.1kHz.


What it’s used for:

Uncompressed audio is primarily used for audio production. The huge file sizes make it unsuitable for use in personal music libraries and streaming services, as large file sizes take up so much memory. However, the uncompressed nature of these files allow for easier manipulation, as the computer does not have to uncompress the data first. This reduces the workload on a CPU when manipulating audio or playing multiple audio streams simultaneously.


Lossless Compression

What it is:

Lossless compression reduces the size of an audio file with no loss in quality. Common lossless formats include FLAC and ALAC. Running raw audio through a lossless codec preserves all of the original data in the file, but rewrites it in a more efficient manner. For example, a string of “AAAAAYYYYAAA” might be rewritten as Ax5 Yx4 Ax3.


What it’s used for:

Lossless format is the format choice for consumers who do not want to compromise on audio quality. The smaller file sizes allow for more reasonably sized music libraries. FLAC and ALAC are also capable of storing metadata, allowing users to sort and filter their files by artist, album, genre, etc.


Lossy Compression

What it is:

Lossy compression allows for extremely small file sizes with minimal loss in quality. Common lossy file formats include MP3, WMA, and AAC.  The goal of lossy compression is to reduce file size by throwing away non-critical data. This includes removing frequencies outside the range of human hearing as well as removing masked or inaudible elements of a track.


What it’s used for:

Lossy compression, specifically mp3, is the most widespread of the file formats. They can be around half the size of lossless and up to 15x the size of uncompressed. This is critical for music streaming or for those who want to cram as much music as possible into their devices. Though it certainly exists, it takes a critical ear to perceive the drop in quality, which is perfectly acceptable to most listeners who are jamming to their workout playlist or listening to lo-fi tracks during their study sessions.


So which format should you use? That depends entirely on context. You’re going to get odd looks if you send an MP3 of your new track to a professional mastering engineer, just as you would filling up your 16GB portable music player with a handful of songs in WAV format. Use the right tool for the job and enjoy the music, whatever format it comes in.


Happy listening!