The art of mastering has undergone some significant changes over the past few decades, moving from a description of vinyl of disc cutting to becoming the de facto final element of the music production process. Mastering engineers often sit in acoustically treated studios, surrounded by equipment designed to enhance a mix and make it sonically competitive with other recordings. Digital audio has enabled the introduction of innovative audio processing techniques and many companies are now providing automated mastering services based on algorithms and machine learning. SoundCloud has teamed up with Dolby Laboratories to produce a bespoke automated on-line mastering system for the platform. Dolby claim that the system “Critically listens to your track” and is the product of “thousands of hours of music analysis” but also contains the input from professional mastering engineers.

When Steven Wilson mixed the Henry Fool Track ‘Heartattack’ for the band’s debut album in 2001, mastering consisted mainly of making sure all the tracks were at similar volume—all other processing was considered as part of the mixing process. For the 2013 re-release of the album, the label insisted on a remaster by a critically acclaimed engineer whose studio was filled with the aforementioned specialist equipment, so I felt that having these two versions of the track available would be useful for a comparative evaluation of the Dolby mastering processing. The Soundcloud website has some useful information on how to prepare your audio for mastering and points out that you’ll need to provide a high-quality mix for the best results. The mastering process itself is simple. You upload your file and are presented with four preset mastering tools. Once selected you can choose different parts of your audio to audition—with or without the mastering process engaged—and define how intense that processing will be. Once you are happy with your audio, you pay a one-off or monthly fee and the file is quickly processed and available to download. I chose the ‘Thunder’ option at a 50% intensity as it seemed the best fit for this jazzy tune.

Comparing the spectra of the original mix verses the 2013 remaster using Queen Mary’s Sonic Visualiser program, it’s immediately apparent that the engineer had cut a little of the frequencies around 300Hz, boosted those slightly under 100Hz and cut those at 4Khz upwards on a gentle shelf. The level was also up by a fraction of a decibel. The Dolby-processed audio appeared to change the overall tonal balance of the original audio very little but was significantly boosted in loudness—indeed it was very close Soundcloud’s required level (-12 LUFS) and well up from the -17 LUFS of the original mix. I felt, after a critical listening session, that the Dolby process did no harm to the audio—which is as it should be, of course. The average level was higher, but there was little evidence of over-compression or limiting or extreme emphasis of any part of the audio spectrum. The four preset options and intensity control should allow recordists to rapidly produce suitable results for a range of genres. The human-mastered version felt as if it had a-little more ‘’weight’ and ‘air’, but I suspect it was a subtle enough of a difference not to matter to most listeners.

I believe that most serious engineers would still want to have more control of the final production, especially if any gross ‘fixes’ are required. But for those unsure of their own mastering abilities, the Dolby process is inexpensive can definitely improve the playback of your audio on SoundCloud—assuming that your mix is great in the first place…

Price: $5 per track, $12 per month and Pro users get ‘free’ tracks.