Written 2016
Streaming services use volume normalization to create a balanced listening experience across playlists and albums. Services like Spotify, Tidal and Apple Music determine an average loudness value for singles, EPs & LPs using a loudness measurement called LUFS. The song, EP or LP's loudness value is used to normalize playback volume to a target level set by the streaming service. The Audio Engineering Society suggests a streaming target level of -16LUFS, however, most streaming services use a louder target level between -13 and -16LUFS. Streaming service's target levels are much lower in volume than master levels preferred by modern artists, producers and engineers. Because of the difference between master levels and streaming service target levels, the louder a master recording is made, the more streaming services will turn down the recording to match their target level. For example, if you master an album to -8LUFS (loud) and submit the files to Spotify, they will turn down the songs playback volume 6dB to match their target volume of -14LUFS.
Streaming Service Target Volumes:
Apple Music (soundcheck on):
-16LUFS
Spotify:
-14LUFS
Tidal:
-14LUFS
YouTube:
-14LUFS
Mastering Levels and Streaming Service Target Volumes:
Below are five different masters of a single song at a different loudness levels (-8LUFS, -10LUFS, -12LUFS, -14LUFS and -16LUFS). The target playback level in the below example is -14LUFS (Spotify & Tidal). Loud master recordings (pink, orange, yellow) are turned down to the streaming service's target volume. Lower level masters are not turned down as much and provide for a greater peak to loudness ratio than albums that are mastered at loud volumes. in effect, the louder you master your album, the lower your peak to loudness ratio. However, this does not impact perceived loudness as you would expect. A more dynamic master will not result in a louder perceived playback. LUFS measurement uses a k- weighting filtering and creating a mix with an appropriate spectral balance will contribute to perceived loudness more than your master level. However, different master levels are attributed to genre. Electronic records often sound more appropriate at louder levels. Some pop or rock records sound more ‘together’ at louder master levels. The decision regarding master level is one of personal taste more than perceived loudness on streaming platforms.
The -8LUFS master (pink) is turned down 6dB, -10LUFS is turned down 4dB, -12LUFS is turned down 2dB, -14LUFS file is uneffected and the -16LUFS file is amplified by 2dB, potentially approaching the service's playback limiter.
Test Files Submitted to Streaming Services:
To illustrate the playback volume manipulation performed by streaming services I have submitted test files of master levels to streaming services. Each file consists of an identical sequences of pink noise calibrated to specific loudness levels. The five songs were submitted as "singles" to streaming services so that each track's volume is assessed individually, and not as an average for the entire EP or LP. Some streaming services have an "album mode" which normalizes the entire album's average volume to the streaming service's target volume and maintains the individual level differences between tracks set by the mastering engineer. The below test files were submitted as singles to avoid the album mode loudness averaging. This simulates what a song would do when it is added to a playlist. You can download the 16 bit, 44.1kHz test files below and the AAC files here.
Test File Info:
"8 Times" -8LUFS, -1.9dBTP
"10 Shoes" -10LUFS, -4dBTP
"12 Dozen" -12LUFS, -5.9dBTP
"14 Team" -14LUFS, -7.9dBTP
"16 Ounces" -16LUFS, -9.9dBTP
Streaming Services & Normalized Playback Volume:
Click the below links to open in-app playlists of the above test files.
The track "8 Times" is mastered 8 dB louder than "16 Ounces", but both tracks play back at a very similar perceived volume on all Spotify, Tidal and Apple Music.
Conclusion:
As you can hear in the above playlists, louder masters do not create a louder playback experience for the listener. Songs mastered at different volume levels are streamed at almost identical playback levels. Even though each streaming services has a different approach to loudness normalization, they all use a target level far below the master volume preferred by many modern artists, producers & engineers. Generally, masters that are perceived louder on streaming platforms have more to do with spectral balance than master levels. For example, excessive mid range or high frequencies will trigger a higher measurement and result in a lower playback level. Determining a master level is a decision about personal preference and genre. Loud master can sometimes sound more contained or together. Extremely dynamic masters can sound more open or loose. These differences are more about what is appropriate for the genre and personal taste. As a music maker you should worry less about level and more about feel, tone, balance and energy. You will read a lot of articles telling you the best levels for masters — do not listen to them. If you prefer the sound of louder masters, make it loud. If you prefer the sound of open and dynamic songs, master at lower levels. The most important aspect you should consider the spectral balance of your masters and the intentionality and clarity of your mastering processing. Obviously, music is not made by measurement and some forms of music simply sound better with more compression and limiting in the master recordings, while other styles of music will benefit from a more gentle approach. You should work with your mastering engineer to determine an appropriate target level that suits your particular project and genre.
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