Mastering from “separations” is an increasingly popular technique and in certain situations has significant advantages. It is a similar, but different, technique to mixing or mastering from stems.

Stems are really just sub groups or collections of related tracks. With stem-mixing, the individual audio tracks are grouped together to allow for independent control and signal processing of each stem and can be manipulated independently from each other. Stem mastering is an extension of this idea and is actually a final phase of the mixing process; not purely mastering.
These techniques have been widely used in the film and audio post production area for some time, particularly with surround sound mixing and mastering. Since the distinction between mixing and mastering is somewhat blurred when working in this way, there are opposing opinions and views on the pros and cons. All these techniques with stems have their proponents and detractors.

Mastering with “separations” differs in that there are a small number of separations generated, each complete with its own effects as they relate to the final mix. The process is similar to traditional mastering except that the mastering engineer can work from these multiple audio files instead of a single stereo file. For example a song supplied as 4 separations would consist of 4 audio files, e.g. drums, vocal, bass and other instruments. Each of these audio files should still contain all appropriate processing so that the mix can be perfectly reassembled by adding the separations together.
A stereo final mix should also be provided as the primary source for mastering and this is what would normally be used unless there are clear reasons not to do so. If there are benefits to using the separations then the final mix still provides the overall guide and an indication of the intent of the mixing engineer or producer.
The advantage here is that the mastering engineer is not required to make any creative production decisions beyond those he would normally be involved with, BUT if there’s something not quite right with the final mix, ie the lead vocal is mixed back too far or not compressed enough, it can all be put together with the right adjustments without adversely affecting the other parts of the mix. The mastering engineer is thereby able to get an improved master without altering the overall intent of the mixer. So this is still just mastering – not mixing.

What does this mean for you?
Well, if there is any doubt at all about providing a perfect mix of your song, then this might be a good insurance to avoid problems later. It can be very expensive, and sometimes simply impractical to re-mix a track if something just isn’t working.
Mastering from separations isn’t intended to provide re-mixes, but it can help to improve the final master and deliver improved clarity, punch and transparency of the outcome.
There can be a downside of course. Firstly, it can take you longer to generate all the separations as well as the final mix which might increase the cost associated with mixing. Secondly, it may take longer to set up and master a track so the costs can be higher. We would always suggest that we discuss your project before commencing mastering from separations and to establish any likely additional costs upfront.

Drums
Bass
Lead vocal
All other instruments/vocals

When mixing, generate the final mix in the normal way as we still may use this for the master anyway, but it is a reference mix in any case.
Then by pulling out or muting the other tracks and their individual related effects, generate the separations. So, for example, to produce the DRUMS only separation, mute all other tracks and non-drum related effects and run the mix through again to record just the drums. Continue in this way to mix down the other separations, always remembering that when added together they should produce the final mix.
Finally, each separation file should be clearly labelled to signify audio content e.g. Drums, Vocal, Bass etc. then sorted into clearly marked folders for each song and recorded onto a CD or DVD.
A typical folder called “GREAT SONG” should contain the following files:

Great Song Drums.wav
Great Song Bass.wav
Great Song Lead Vocal.wav
Great Song All Other Instr.wav
Great Song Final Mix.wav

So is all this worth it?!
We have a few clients who have, for various reasons, not been confident in achieving a great final mix and have produced separations which we have mastered with superb results compared to just working with the stereo mix.

At we believe that in the perfect world, working from a great mix with properly integrated components is still the ideal way to remain absolutely true to the intent of the mixing engineer and/or the producer. The mastering engineer can focus on mastering and everyone is happy.
However, the world is often not perfect and it is possible to achieve better results with separations than having to work with a mix which may have some deficiencies.
If you work with separations as a matter of routine, it may save you a lot of heartache, time and money down the track

It is your choice, but we’re happy to be able to offer that option!