Audio file formats: what they are and why they are important for listening to your music


The type of audio file format (or codec) used by music streaming services and download sites can have a big influence on the sound quality you experience from the music you enjoy listening to. Effective audio compression techniques manage to compress large amounts of audio data into more manageable file sizes by removing some information from a recording, but the process can have a detrimental effect on the overall sound quality of your favorite tracks and your listening experience. Ultimately, this means that you hear something less than the artist or artists originally intended when recording, but if you notice a degradation in sound quality, it may depend on the type of equipment you use to listen to.

To get the most out of your music, you need to hear it on great-sounding gear that sounds natural and produces a full range of frequencies, like the models found in our best headphones, best wireless headphones, or the one of the best bluetooth speakers. And to find out which audio formats provide the best sound quality for your tracks and as the artist(s) originally intended, read on…

Digital audio types

Lossy Audio

It is a compression technique that does not decompress audio files to their original amount of data. Lossy methods provide high degrees of digital compression, which results in smaller files. In these cases, some sound waves are dropped which affects the sound quality in an audio file. Lossy compression is not recommended in professional environments where high quality is paramount.

Lossless Audio

It is a compression technique that decompresses audio files to their original amount of data. Lossless methods can provide high degrees of digital compression, but there is no loss in size or sound quality. Lossless compression is ideal in professional audio environments where full files are required. Lossless compression music formats include FLAC, ALAC and WMA Lossless.

Uncompressed audio

This is an audio file to which no compression is applied. Uncompressed audio files sound the same as when they were recorded. Examples include PCM, AIFF and WAV formats.

Audio codec formats

iPhone playing music and showing colorful sound wave on screen

(Image credit: Shutterstock)

FLAC (free lossless audio codec)

FLAC delivers CD-quality sound in a smaller file size than an actual CD. It is also a non-proprietary, open-source codec ideal for software developers who want to use lossless audio. Although FLAC files are easily accessible, they can be six times larger than MP3 files, so they take longer to download. This format is not compatible with all devices and software, but the sound is excellent when streaming via Wi-Fi or Bluetooth.

WAV (waveform audio format)

WAV is an uncompressed audio format that is ideal if you want to get the original recorded material without compromising sound quality. WAV files are ideal for shorter sound bites because their uncompressed form means they are large files, making them difficult to stream. This is especially true in cases where bandwidth is limited. The audio from these files is crisp and the sound is good over Bluetooth.

MP3 (Moving Picture Experts Group Layer-3 Audio)

MP3 is one of the most popular audio codecs and became a household name for its ability to reduce file sizes for the first wave of solid-state music players. MP3 files use lossy compression, which significantly compacts the audio. In some cases, MP3 files can be 10 times smaller than WAV files. This compression method is versatile and works on almost any playback device.

Although MP3s are great space savers, the bit rate at which they are recorded has an effect on sound quality. For example, MP3s encoded at 128kbps don’t sound as good as those encoded at 320kbps, but listeners should consider whether they prefer sound over storage. MP3s have been used for streaming in the past, but with high resolution streaming becoming more popular, they are not the only codec format option available.

WMA is available in lossy and lossless WMA formats, giving listeners some choice. Generally, WMA files are smaller than their uncompressed counterparts and similar in functionality to MP3 and FLAC files. Although WMA offers versatility, it is not compatible with all devices, especially Apple devices. It is possible to stream audio in WMA format, but major streaming providers do not use it. Fortunately, for the average listener, this format sounds great over Bluetooth. Only critical ears would hear a difference in quality.

ALAC (Apple lossless audio codec)

ALAC sounds identical to the original recorded audio, but is compressed to a smaller size without dropping any bits. ALAC works primarily with Apple products, which makes the format a bit limited for people without iOS devices. It also takes longer to download than lossy formats, but it sounds good over Bluetooth. It is possible to stream with ALAC, but this codec is not commonly used due to its incompatibility with non-Apple devices.

AAC (Advanced Audio Coding)

AAC is another lossy codec that delivers small audio files and works great for online streaming. AAC files are not useful if you need a close replica of the original recording because bits are removed. But it sounds perfectly fine otherwise. The compressed file size is ideal for mobile devices and is used as the default format for Apple Music and Tidal.

Ogg Vorbis

Ogg Vorbis is an open-source, patent-free audio codec ideal for streaming over the Internet without compromising speed. Ogg Vorbis delivers impressive sound at lower bitrates than other lossy formats. The only downside to Ogg Vorbis is that it compresses audio and strips data for smaller file sizes. However, it transfers audio quickly and sounds great over Bluetooth. Because the average music lover doesn’t use this format to compress audio, you won’t find many compatible devices – although the fact that Spotify uses it for all phone and desktop streaming means it’s widely used.

MQA (Master Quality Authenticated)

A lossless format that uses a sophisticated compression conditioning process to compress and decompress large audio files to enable efficient data stream transfers. The format is used by Tidal on its High-Resolution Masters content to provide high resolution (above CD quality) to its music content. MQA files can be packed in any lossless container such as FLAC, WAV, or ALAC file formats, but you will need compatible hardware, such as a music streamer or portable music player, or software such as the desktop application Tidal, to decode MQA files.


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