Mastering is the final stage of music and audio production. It is the process of optimizing and preparing a stereo final mix for various physical media and digital download formats.
There are many processes that may need to be addressed during mastering. These can include: equalization and tonal balancing, dynamic compression/expansion, harmonic saturation, stereo width adjustment/enhancement, peak level limiting, noise reduction, de-essing and de-clicking, editing, phase correction, fading in/out.
During mastering it is important to carefully balance the music so that it will translate accurately on any playback system it may encounter. Audio should be optimized for the most expensive boutique hifi system, the cheapest single speaker radio, the largest Funktion One club system or smallest smartphone. For electronic music it is important to control and correctly balance the bass and low end content so that the music sounds great when played at high sound pressure levels in clubs and public venues.
Every mastering job is different and may require any of the processes mentioned above to correct or enhance certain aspects of a recording. Some of the music I receive will benefit from a touch of analog dynamic compression, and tonal balancing (EQ). During mastering I will adjust for a correct musical balance, often making small dips and cuts to certain prominent frequencies and areas in the mix.
Certain genre specific areas may be enhanced. House and techno? The bass drum should be clear and prominent, with controlled low end and detailed mid and high frequencies. Ambient and drone music should be open and expansive. I can achieve these careful adjustments with very high precision in my acoustically treated and calibrated studio. Full range monitoring reveals the low end, and high quality digital to analogue conversion allows me to hear minor details that may need to be delicately balanced to enhance the listening experience. Stereo width may need to be adjusted (widened or center focused), and editing/volume fading of the beginning and end of each track will be required for smooth and clean transitions. Finally, I will use a limiter to hit current loudness targets for any music distribution, physical media and music streaming platforms required for the release.
Integrated loudness and peak levels
The loudness wars are over! Rejoice! In the not so distant past, commercial music was being pushed to the extremes of loudness using certain mastering techniques. Once the maximum amplitude for a digital audio signal is reached (0 dBfs), then perceived loudness can be increased further by using audio compression and brick wall limiting, to reduce the dynamic range of the music. Extreme dynamic range compression and limiting will make your music loud, but it will also add distortion artifacts to the audio signal, and the music will suffer as a result, sounding fatiguing and uncomfortable when listened to for extended periods.
Over the past few years the major music streaming platforms such as Spotify, YouTube and Tidal have started to apply loudness normalization to all the music on their sites, which means a master that is louder than the current threshold set by the streaming platform will actually be reduced in volume. A loud master is not needed to 'compete', and will actually sound worse than a less loud and more dynamic version of the same music.
Anyway, I have always been sensible with loudness and limiting. Too much dynamic range reduction will always have a detrimental effect on the sound quality of the music. I master a lot of bass heavy techno and electronic music which gets played by DJ's in clubs and live venues, so I have always pushed these tracks less to achieve a better quality low end. Compression and limiting are powerful tools when mastering, and applying them sensibly will allow a correctly balanced (dynamic) master to sound much better on a club system at high volumes, than an already pushed to the extreme loud master.
When I set final loudness, I will closely match the latest integrated loudness and peak level target recommendations for a variety of media formats. I can also supply a separate 'streaming optimized' version which will closely match the current peak level targets for any of the current commercial streaming platforms (Soundcloud, Spotify, YouTube etc) Overall, I can achieve a final master that provides a healthy amount of volume whilst retaining mix transients, musical dynamics and bass content.