Updated: Mar 24
Many people ask the question what is the difference between mixing and mastering and I shall attempt to answer that today! Once a song is recorded, the final two stages of the audio production process are mixing & mastering. Both are important separate stages, but these days sometimes tend to get merged together with so many people doing everything themselves. Is this the best way to make a great record? Almost certainly not, but before we discuss that - let’s define what each is.
Mixing is the stage before mastering that is essentially balancing (in fact a mix engineer used to be called a “balance engineer“ back in the glory days of big studios like Abbey Road) and combining individual tracks together to form a stereo audio (or multi-channel for a movie, perhaps ) file after mixdown is complete.
It’s highly subjective, artistic and while technical also has a large creative element. Technical elements might include organising the session, labelling and grouping tracks, cleaning up noise, adding fades to individual tracks, performing edits, fixing bad drum hits, tuning vocals, instruments or whatever is required to get the track in top shape.
The artistic side involves deciding how to balance the tracks, where to place them in the stereo (or surround) spectrum, whether or not and how to add effects like reverb, delays, modulation, saturation, how to EQ each individual element individually and to fit together sonically with space for each other or handle dynamics with compression, and what to automate to create level changes throughout the song to piece together a finished sounding, full, wide and dynamic record. This can usually take a few hours to several days in some cases. The legend has it that Thriller was mixed over 90 times…and in the end they used mix TWO. In other words, it’s easy to overthink things! Eventually when the final mix is finished, the stereo finished mix is ready for the next stage - mastering.
What is mastering? First of all, it is the last step of quality control. Your mastering engineer will (hopefully!) be listening in a well designed acoustically accurate room far better than yours and be able to make the small EQ changes needed to fix any minor issues and enhance the spectral balance of your mix. Many people are mixing on weird setups in less than ideal rooms especially these days, and this is a great opportunity to compensate for that. They may apply compression to change dynamics if need be, tighten the bass, increase the stereo image, de-ess….whatever is needed to get the best sounding version of your song possible that will translate on every playback system. One of the big problems people who self master is this: You hear things the same way in the same room and set up and literally cannot compensate for what might need to be done. You might be saving money, or making more for yourself if you're one of *those* engineers but you are cheating the song and record. Lastly yes - they will make it commercially loud using compression, clipping and limiting, though that isn’t the MAIN purpose of audio mastering which many people seem to assume!
There’s also the consideration if an album is being compiled of how the songs flow into each other - the question isn't always how to master a song, it's sometimes how to master an album as a whole - you can’t have songs being random volumes track to track, or varying wildly tonally for a good listener experience! The mastering process takes this in hand and makes sure the collection of songs sit together as a whole. Finally, there is the preparation for the assorted formats - perhaps a red book master for CD, files for vinyl, or streaming all of which have a slightly different set of requirements for best results. See any Facebook group you like for suitable confusion, misinformation and arguments.
Both mixing and mastering have a huge impact on the quality of the finished project and in almost all high-level productions they are separated to maximise the gains possible from a different set of ears, rooms, and objectivity that this provides. People are even mastering in GarageBand, or refer to the process as making a mix master, but why short change your music? After all, once it is released it is out there FOREVER, so give it the best chance of success possible. Your "I do it ALL" ego or lack of budget are the enemy of art.
I hope this has explained the key differences between mixing vs mastering and if you’d like to read more articles on mixing or mastering please have a look at the articles for artists available elsewhere on the site. Happy music making! If YOU need a great professional mix, of course...feel free to reach out and say hello.