Using an advanced EQ across the entire mix can provide some welcome sheen across the board, but preparing stems for the mastering engineer could mean losing that processing. We show you a way to keep mix processing intact for stems.
Stems Versus Mixes For Mastering
Traditionally, preparing mixes for mastering was straightforward. The mix engineer applied any mix bus processing (such as compression) to taste, avoiding excesses where possible. The use of mix EQ could have been considered redundant on the understanding that individual tracks should constitute the right tonal balance when summed. Bounces or mixdowns were produced, with appropriate headroom for Mastering to work with.
More recently, stem mastering has become an option where mix revisions are not possible. These afford an insurance policy for both mixer and mastering engineer, where (usually stereo) submixes of tracks and effects are brought together for the mastering engineer to work within their DAW. In a best-case scenario these stems’ levels can be left at unity so as not to alter the intended balance, but the control is there if needed. This can be simple level tweaks or targeted processing.
Where To Process?
With advancements in what audio plugins can do across entire mixes, the concept of EQ applied across the mix’s main outputs becomes something that can compliment track processing back upstream. Certainly, any tool that offers an extra ‘pair of ears’ can’t be a bad thing; the engineer can simply discard the processing if it’s not bringing anything good to the party.
At first glance, exporting stems for mastering purposes misses out on any mix bus processing, simply because rendering happens either upstream of mix processors, or because that processing needs a sum of all the stems to behave as a whole mix (as is the case with compression, or an intelligent process that needs to analyse the entire mix).
‘Mix’ Processing For Stems
Whenever a processor’s action must be driven by external audio, there is sidechain processing. With a little thought, it can be used to solve the stems-with-mix-processing conundrum.
Each stem has its own instance of the ‘mix’ processor. Each of these has the unprocessed mix as its sidechain input. The DAW needs to support delay-compensated stereo sidechaining for this to work.
In the case of an intelligent EQ such as Gullfoss, each instance can analyse the entire mix in its sidechain, while applying mix-appropriate shaping to each stem.
Stems are bounced with processing, which when summed behave like a mix with common processing. The mix engineer can apply a ‘sound’, while the mastering engineer retains extra options.
Watch in the video as we listen to Gullfoss Master across a stereo mix. We then use Gullfoss Master edition’s stereo sidechain capability to apply mix-appropriate shaping to individual stems using the technique above.
Rather than choose between a sound for the entire mix as determined by the mixer, or the flexibility and extra control afforded by stem mastering, exploiting a common sidechain signal solves the problem. As ever, the aim will always be to perfect the mix, with mastering serving as light-touch process prior to distribution. Nonetheless, when using this technique, engineers have the best of both worlds, which comes into its own with intelligent processors that are content-aware.
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