# Mastering of stems...Advice please?



## paulvanderwalt (Apr 17, 2018)

Hi

I've got some library tracks which I need to send mastered stems of, but I'm finding it really hard to keep the balance. 

Please note that I mean that I need to master the actual stems, not to master WITH stems. The client needs to be able to drop all the separate tracks/stems into a project and it needs to have the loudness and mix balance of the original stereo mix-down. 

This obviously has to do with the limiting and compression in my mastering chain and the only thing I can think of is to pretty bypass those to keep the mix balance. But then I lose the original loudness. 

I'm at the point where I'm just going to tell them to turn it up if need be as I can't get the same loudness and retain the mix compared to the original stereo mix. 

I hope this makes sense. Is there anyone else who have experienced this? Any tips or advice would be much appreciated!


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## aaronventure (Apr 17, 2018)

If all you have on your master is a limiter and a compressor, they should have no trouble achieving the same thing, just tell them what you did. Send them screenshots or write it down. If they need stems, they must have a person responsible for mixing it all together so they'll know what you're talking about.


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## Henu (Apr 17, 2018)

First of all, this is a really tricky situation. Technically, when I expect stems to be asked, I try not to use any sort of master compression or limiting at _any_ stage unless doing strictly some soundtrack/ to be released material. (Everything else is ok, though.) But obviously you can't go back to that situation again. 

What you could do are a couple of things. You could route all stems into a new bus and try to carefully compress/ limit each bus individually to match the sound of them in the original stereo file. For this you of course need the original file running in sync in your DAW for constant A/B testing. It's not the most optimal workaround and will not give you a 100% accurate result but it's better than nothing.

You could also try some really weird side- chaining too. _Technically_, you could once again route all your stems to their own buses and treat each of them with a side- chain compressor/ limiter so that your compressor would listen to the rest of the stems (while being at zero volume, so sidechain needs to be pre- fader) and act accordingly compressing your audible stem based on the others. This is something I was about to test myself a couple of years later when I was in the same situation but in the end the stems weren't luckily needed. However, I'm not actually sure it would work, but I'd at least give it a shot in an extreme situation, haha!


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## Mihkel Zilmer (Apr 17, 2018)

@Henu is on the right track. Side-chain compression and limiting is what you'll need to send them mastered stems that are (almost) identical to your mastered mix.

There's two ways to achieve this, both rely on each of your stem compressors being able to listen to a fully unprocessed version of your mix.

1) Export a copy of your uncompressed / unlimited mix. Throw that on a new audio track and use it to feed your stem compressors / limiters side-chain inputs.

2) If you want to do this in real-time then you need to branch out your stems into 2 sets. One set will be without any inserts, and they will feed a side-chain mix bus, with no output. The other set of stems will have the compressors on them, with their side-chain inputs listening to the unprocessed signal from your side-chain mix bus.

PS very few limiters actually have a side-chain input. I use Pro-L2 for this purpose.


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## kavinsky (Apr 17, 2018)

just set a number of busses that mirrors your stem count and apply compression/processing separately. place a safety limiter on your masterbus and adjust the output fader so there's no gain reduction and work exclusively on your stem busses to achieve desired sound.
this approach has a lot of workflow benefits.


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## VinRice (Apr 17, 2018)

Side-chain limiting as others have said. It's not hard once you get your head around it.


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## reddognoyz (Apr 17, 2018)

VinRice said:


> Side-chain limiting as others have said. It's not hard once you get your head around it.



This is the only way to truly repro your full mix with stems.


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## gsilbers (Apr 17, 2018)

stem deliveries like this are highly overrated when it comes to technicalities. most engineers tend to think that the stems has to add up to EXACTLY the end mix. having recieved these when doing re-recording mixing, as well as collegues.. its not that black and white. they can be somewhat different. 

i suggest sending the stems to busses with EQ, comp, reverb and limiting. so dont use sends on indivudual tracks stems. its a good option but only do it for specific fx like dub delay and such. not for normal instrument type verb and delays. clients/mixers dont like that as its another stems they have to deal with that it couldnt been added to the other stems. i know its for a music library but they deliver to clients so similar principal. 

anyways. thats it. just adjust eq, comp and limiter settings on the busses and record back the stems into the daw and out the master channel bus that also gets printed at the same time. you can add a compressor or limiter on the master bus but dont change the levels to more than 3-6db. 
i woudl also redeliver the final mix so its the subset of the stems. if its possible of course. 

and its not a real mastered stems obvously, they just want for their clients to be able to edit the music on stage if something comes up like removing a piano melody on a actors dialog etc so they can use the stems and they go and edit fast the mix final to "stems minus piano stem" and it doesnt sound way to different or level difference is not huge. 

anyways, if you can convince them to accept a new final master mix made from the stems (that you reroute to busses w a mastering chain) it will be easier than to recreate the final mix already mastered already delivered.


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## JohnG (Apr 17, 2018)

gsilbers said:


> stem deliveries like this are highly overrated when it comes to technicalities. most engineers tend to think that the stems has to add up to EXACTLY the end mix. having recieved these when doing re-recording mixing, as well as collegues.. its not that black and white. they can be somewhat different.



@gsilbers is right. I know sometimes they insist they want the sum of the parts (the stems) to add up exactly to the whole. But really, that's kind of nonsense. If they are monkeying with your mix in the first place it's kind of not your problem any more.

I've done it both ways -- with and without the stereo master exactly matching.

1. Stereo master doesn't match: provide stems with nothing but individual reverb, along with a stereo master that might have additional compression / EQ / limiting / etc. 

2. Stereo master DOES match -- put each stem through whatever compression it's going to get and then print a stereo master by just routing all the stems to a single bus, with the faders of the stems set to zero.

I still agree with gsilbers that most of the time, if they start digging in to what you provided and doing "their" mix, there's little likelihood that it matters whether in fact the stems add to the master you provided. Or that they will even notice / compare.


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## Uncle Peter (Apr 17, 2018)

aaronventure said:


> If all you have on your master is a limiter and a compressor, they should have no trouble achieving the same thing, just tell them what you did. Send them screenshots or write it down. If they need stems, they must have a person responsible for mixing it all together so they'll know what you're talking about.



What aaronventure said.

If fi is your processing and each xi is a track, you're being asked for f1(x1) + f2(x2) + ... + fn(xn) = f(x1 + x2 +...+ xn). Not happening, you may well get an approximation. The whole point of the compressor/eq/limiter on the master bus is that it is responding to the summation of the frequencies and 'gluing' it all together.

Actually, that's a good idea for a plugin - if it doesn't exist already. Split/back allocate the final processed mix to stems to be recombined- using the original stems somehow as a guide. Wonder how hard that would be to do.. I'm sure the Celemony guys could crack it.


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## Brendon Williams (Apr 17, 2018)

VinRice said:


> Side-chain limiting as others have said. It's not hard once you get your head around it.



Yep, this is the way to go. Not all limiting plugins can do this, but in Fabfilter's Pro-L, they call it "external side chain triggering." All you need to do is enable it by clicking the orange button in the bottom left corner of the plugin (see image) and then set the side chain input to a bus that has the full mix going through it.


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## charlieclouser (Apr 17, 2018)

Well, that is the way I always prepare my scores - with individual limiters / "mastering processing" on each stem's sub master, all stems combined at unity gain into a composite mix, and no further processing on that composite mix.

My stems are definitely being compressed - sometimes really heavily, and if you import the individual stems into a blank session and combine them with all faders at zero, the result absolutely matches the composite mixes that I deliver - because that unity-gain summing of those stems is exactly how I made the composite mixes in the first place.

I *do* use send-based reverbs and delays, but I have a separate set for each stem - individual tracks and instruments get sent to the appropriate effects whose outputs go into the same stem sub master as those instruments, so no overlap or crossed output issues there.

By precisely manipulating the output level of the limiters on each stem sub master, it's fairly easy to get the composite mix to reliably peak within a couple db below full scale, with no overs and no suspiciously quiet passages. Lately I use Waves L3-LL MultiMaximizer as the last processor in the chain on every stem sub master, with the output level set somewhere between -6 and -9 db depending on the content.

Somewhere on this forum is a long and overly-detailed post I made a few years ago that has screen shots of my output sub master matrix in Logic's Environment, showing the routing, stem-specific effects busses, etc. I think it's post #6 on this page:

https://vi-control.net/community/threads/setting-up-logic-pro-9-for-stems.22462/#post-3581445

Even though that's from seven years ago, in Logic v9, the principle is still the same. Stem sub masters are Aux Objects which have processing, and *sends* from those sub masters go to busses, which feed a set of sub masters for the composite mix. This allows each stem sub master to be routed to a hardware output (for printing to my separate ProTools machine) *as well as* feeding into the composite mix sub masters by way of the sends.

It's not exactly how you'd set it up for printing stems within the Logic project, but almost. Does use up a lot of busses though.


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## paulvanderwalt (Apr 18, 2018)

gsilbers said:


> stem deliveries like this are highly overrated when it comes to technicalities. most engineers tend to think that the stems has to add up to EXACTLY the end mix. having recieved these when doing re-recording mixing, as well as collegues.. its not that black and white. they can be somewhat different.



Yeah, I think in this case it's okay if it's just close to the stereo mix. Which helps.


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## paulvanderwalt (Apr 18, 2018)

Brendon Williams said:


> Yep, this is the way to go. Not all limiting plugins can do this, but in Fabfilter's Pro-L, they call it "external side chain triggering." All you need to do is enable it by clicking the orange button in the bottom left corner of the plugin (see image) and then set the side chain input to a bus that has the full mix going through it.



I am not sure if I have any limiters that can do side-chaining (I'm going to have a look) but the Pro L is on my list. Thank you.


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## paulvanderwalt (Apr 18, 2018)

VinRice said:


> Side-chain limiting as others have said. It's not hard once you get your head around it.



I am familiar with and do use side chaining in my production, I've just never used it on a limiter like this.


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## paulvanderwalt (Apr 18, 2018)

Uncle Peter said:


> What aaronventure said.
> Actually, that's a good idea for a plugin - if it doesn't exist already. Split/back allocate the final processed mix to stems to be recombined- using the original stems somehow as a guide. Wonder how hard that would be to do.. I'm sure the Celemony guys could crack it.



I would love a plugin like this. It would save me a lot of time.


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## Uncle Peter (Apr 18, 2018)

paulvanderwalt said:


> I would love a plugin like this. It would save me a lot of time.


Just daydreaming here..

I suppose it would work by sending the output of each stem to the plugin as an input. The plugin would monitor the final mix and compare the summed stem audio (pre-processed). It would then have to adjust the volume/eq etc of each stem so that when the stems are recombined it matches the processed mix.

You can imagine that each stem may end up sounding quite weird. There would have to be some kind of parameter which determines how coherent each stem sounds – i.e. no wild cuts in low end frequencies/overall volume all of a sudden. But I imagine this would be to the detriment of how close to the end mix the recombined stems sound. So the user would have to experiment with this setting. Also, when the mix levels of the final stems change it could end up sounding quite bad. It's probably a terrible idea - but you don’t know until you try!

Once happy, the user processes the result of the plugin and it outputs the adjusted stems as audio files. Job done.

For mix and match, client use stems. The best strategy may indeed be to perform most of the processing at the stem level – with just light compression/eq on the masterbus. Therefore when this (imagined) plugin is applied the effects on each stem are not so noticeable.

What does one need to do this... some signal processing - Fast Fourier Transform algorithms/C++ audio scripting and ingenuity I guess.


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## Chris Maxwell (Dec 11, 2018)

Brendon Williams said:


> Yep, this is the way to go. Not all limiting plugins can do this, but in Fabfilter's Pro-L, they call it "external side chain triggering." All you need to do is enable it by clicking the orange button in the bottom left corner of the plugin (see image) and then set the side chain input to a bus that has the full mix going through it.


I'm working on TV shows and want to do this with the FFL2. All my tracks are grouped into auxes like Strings, Drums, Brass etc.... do i take the Auxes and send them at unity gain post fader to single Aux and turn off the output then have the L2 side chained to that Aux? The devil is in the details for me since this stuff is not part of my normal workflow.


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## Nite Sun (Dec 11, 2018)

I may be overthinking, but I've achieved side-chain stem compression by using two sets of stem groups. First I have one set of the stems, eg: 100 - Vox, 200, - WW, 300 - BRS, 400 - STR etc which all send to a second set of equivalent stems, eg. 101 - Vox, 201 - WW etc. Then I also send the output of each stem in the first set to a single aux (with the output turned off). This dedicated full-mix aux can then be fed as a side-chain input to any dynamic processing plugins on the second, printable set of stems.


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## chrisr (Dec 11, 2018)

This do-able reaper too.

I posted about it some time ago (https://vi-control.net/community/th...stems-via-sidechain-from-summed-master.58947/) - although now I achieve the same thing in a slightly different way that's probably more logical.

The way I do it now is to use the ability of reaper to hold multiple/interchangeable streams of audio on a single track (in this case the 2-buss, but actually in my mix template it's a music sub-mix buss because there's other stuff going on besides the music).

All the plugins/processes on my the master/summing track *must support true side-chaining* for this to work - hence why support for side-chaining is now the first thing I look for in _any_ master-buss FX - (not just compressors).

Essentially there are 2 stereo streams running to the bus - the first is the full mix, the second is any stem of that (up to and including the full mix).

Each plug on the buss is inserted twice in sequence, the first instance is always fed by the stem material (1/2) but with the full mix as the input via sidechain (3/4). The second instance is fed by and outputs just the sidechain (3/4).

Any FX can be stacked as necessary - with the in/outs of the plugs organised so that full mix essentially runs down the second instance of each plug like any regular stereo fx chain, and the actual output (1/2) runs down the first instance of each, with the signal always processed by the full mix (3/4) side-chain key input.

The mix can be slammed completely square(!) if desired and then bounced out to as many stems as needed and the stems will still null completely if placed against the inverted full mix. This is true regardless of any volume automation / fades etc that are made as part of the mix.

To use this method you *have to* set up your reaper track sends to the 2-bus in a particular way so that you can still balance the mix and use volume automation etc... and there's also a slight compromise about how you bounce out each stem - you can't just mute the unneeded parts because it will screw up the summing - you need to turn down the individual master track volumes rather than use mute/solo. It's a slight pain ... but the pay-off is well worth it, for me at least.


*edit* - if anyone reads that other thread - the way I do it now is much more sensible and resource efficient, although the end result is the same.


*edit 2* - If anyone is reading this and thinks it's too complicated, I should mention that it's all set up in my mixing template and mixing with it just feels like any other mix really, with a couple of small caveats.

and also - of course if a stem is later removed from the mix the rest of the audio will still seem to pump around it - of course - possibly not so great.


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