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Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

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Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by Mister Fox » Sat May 27, 2017 3:04 pm

The following questions pop up over and over.
  • What do you mean when you say "try to not(!) pre-master the track (please no overuse of mix bus treatment)"?
  • shouldn't we just use fixed loudness values on the final render and the participant can decide how much treatment he uses on the summing bus?
  • how much treatment is too much?

These are all valid questions that I'd like to address with this post. In fact, there are Rules/Guidelines about this given already, and I posted several times how to perform best in this situation. But it seems to be a recurring question, so let us please discuss/tackle this topic more in-depth.




:?: THE CONCEPT OF THE MIX CHALLENGE...

The "Mix Challenge" is as the name implies. It is a mixing competition. The focus is on properly setting up a project, edit it (cutting tracks "clean", setting proper fade in/out), mix it within giving specifications and bonus-rules, then export it (re-record for hardware-only users). During the mixing process, you can use whatever tools you feel like (within given limitations), or any form of mix techniques you know (vintage mix techniques, Brauerize method, mix-in-mono first then spread it out to stereo, etc).

But the main idea is to understand how mixing works, gather experience (if you're inexperienced) and practice techniques, maybe completely overhaul your up-to-this-point used workflow (some users tend to not gain stage, and constantly exceed the limits of the digital meter, adjust the summing bus fader, etc).




:?: WHAT IS MEANT WITH "TRY NOT TO PRE-MASTER THE TRACK"?

As mentioned in the previous point, your focus should be on mixing - and mixing only(!). These days, mixing and "mastering" (technically pre-mastering) is considered to be one and the same step. But the Mix Challenge tries to get away from that and draw distinct lines. Reason being for possible further challenges(!) and for the real world, giving the mastering engineer way more room to work with of course.

If you'd handle all the EQ fixing, stereo field override, limiting and loudness raising yourself already during/after mixing - then the mastering engineer has no choice but to use(!) this as source for his further edits. Making things just more and more loud. Or trying to fix issues that were messed up during the mix with a global EQ/compressor, etc.

I am fully aware that the lines are thin these days. And there are always the questions:
"how much is too much?", "what is considered tasteful summing bus treatment?", "how to do it right?"

The short answer is, that there is no definite / right solution for this. There are only recommendations.

Ultimately it is up to you, the mix engineer, how much wiggle room you give the next person. Though keep in mind, the audio realm is currently changing. "Loudness Normalization" is a huge topic since early 2010s (and since 2017 now more than ever). Meaning that your drastically over-compressed track is being reduced in loudness to go down to a certain value. Your now "limited" track has to compete with material that still has his transients and dynamic (not to misinterpret with dynamic range!) fully intact. Which production do you think would sound better?

Notable examples to this topic:
Metallica's "Death Magnetic" from 2008 or Imagine Dragons' "Smoke + Mirrors" from 2015
vs Michael Jackson's "HIStory – Past, Present and Future Book I")




:?: WHAT CAN BE CONSIDERED AS GOOD HANDLING OF THE SUMMING BUS?

Let's start with an illustration:
Image


This image shows 4 possible ways how to handle a production on the summing bus (or "master bus" in certain hosts) without overdoing things. From "no treatment" to "considered borderline too much". This is just an example, not a clear rule.


EXAMPLE 1 - Metering only:
In this example, there is of course no further treatment happening. You mix as well as you can, and only check for levels or frequency issues on the sum of your available mix console.


EXAMPLE 2 - "The Glue Effect":
For some productions, there is a need to "gel" things together. Which in turn emphasizes certain instruments and pushes things even further. This was (and still is) a famous technique especially used in the early 90ies for Grunge and Rock productions. EDM productions also use summing bus compression for added "impact" (sometimes even with specific setup multi-band compressors). You might have heard of this in video tutorials as so called "record enable technique". However - don't misinterpret this as "mastering and loudness raising". It is an artistic choice.

The idea here is to have a moderate-to-fast responding compressor with a ratio of 2:1 to 4:1 "compacting" the incoming signal by 1,5dB to 3dB of gain reduction absolute maximum (ideally, not higher than 2dB of Gain Reduction). No output gain compensation, no raising of the volume (and therefore the perceived loudness). The effect is supposed to be subtle, but having enough impact to get the feeling that there is something "larger than life" happening to the mix. Or in other words "glue things even more together".


EXAMPLE 3 - The Console / Tape Effect:
This topic precedes "The Glue Effect". Due to the revolution in recent years with "console modeling", you see this setup more and more as deliberate artistic/sound design choice. With the right tools, you create an ITB (In-the-box) analog mixing console (some hosts have this built in, HARRISON MIXBUS comes to mind), and would maybe even like to print the mix down on to tape. So you see/use a console emulation type plugin on the summing bus (resulting in varying amounts of crosstalk and saturation), but also a tape machine (more saturation, possible sound shaping due to tape head bump effect, "tape" compression). Back in the days, this was the only way to record and process a production. These days, this technique is used to spice up mixes that might sound too digital, or if you want to re-create vintage mixing techniques.

Notice that there isn't an additional compression or EQing in the signal chain. Not only that, the console and tape machine is setup to work at their hotspots of -2VU to +2VU. Like "The Glue Effect", this can add something "larger than life" to a production, while not overdoing it as much compared to "The Glue Effect" (which can already be a precursor to pre-mastering).


EXAMPLE 4 - Console, Tape/Compressor and Fixing-EQ (fix one-EQ-band):
Now we're getting into the territory that I (personally) start to(!!!) consider "borderline too much". We now have the console (crosstalk, saturation), the tape machine (head bump, saturation, compression) and then you realize "whoops, now I have too many mid frequencies". In this case, it is still(!) valid (in my opinion) to add another EQ, and then turn down one frequency band only, maybe more if there is another problematic frequency. It can still considered be "general sound design". But then the lines turn thin - everything after that, clearly goes into "fix the mixdown" / mastering territory


The bigger picture here, is that the mixdown should sound great to begin with. The next step (mastering, porting into the right release format) is then only to emphasize on the mix with so called "Fairy Dust" (if needed!).




:?: THE THIN LINE...

Now we're treading on a very thin line. "Was the summing bus/master bus handling too much?", "What about the so called 'Fairy Dust'?", "but if we add more to the summing bus, while keeping a certain loudness value, the mastering engineer still has a lot to work with, no?"

All valid arguments. However, notice that this setup didn't use either of the following:
  • mid/side treatment / enhancement (stereo widening techniques, bass narrowing)
  • adding "Fairy Dust" (parallel EQ, broad "character EQ", more saturation)
  • multiband compression (if needed! Compacting the signal even further, which leads to...)
  • limiting
  • loudness adjustments
The focus has been (and still is) on mixing the production. You literally "fix it in the mix", not on the sum. And yes, even though CPU power these days can be trivial, not to mention that it's a very small step towards "mastering". Your focus in this challenge should be on mixing and work as best as possible, only add "minor coloration" (can be a subtle warm EQ, a "Glue Effect", very subtle stereo image enhancements through crosstalk or similar). Then later go from there...

I am fully aware that the line is thin. But there is a purpose behind it. These days, we have access to near unlimited tools - but will that be the case in a studio you're not familiar with? Or what about a pure analog large scale hardware console? This is the focus of the Mix Challenge - it's a learning experience.




:?: WHAT ABOUT SETTING A LOUDNESS VALUE FOR THE MIXDOWN THAT EVERYONE HAS TO ADHERE TO?

This has already been addressed in the Rules/Guidelines of the Mix Challenge.

It is recommended to work with a reference level of either -20dBFS = 0VU (SMPTE RP 0155 recommendation) or -18dBFS = 0VU (EBU R68 convention).

Simplified, you use a combination of a VU (without weighting filter) and Digital meter. Then you try to mix in a way so that your maximum signal strength (dBTP or dBFS) does not exceed -1dBFS, while your average signal strength (VU w/o weighting filter / RMS realtime with Dorrough specs) does hover between -21dBFS to -15dBFS (RMS realtime) on average or -3VU to +3VU.

There are plenty of articles about that on the KVR Marks of the CTO of the Mix Challenge, and now even on the Mix Challenge Forum (in Production Techniques)


I do not recommend to go with LUFS during mixing music, as this particular metering tool (ITU-R BS.1770-x specs / EBU R-128 and ATSC A/85 are presets of it) has it's main focus on mastering and broadcasting. Also, there are still many people out there, that don't know the fine details of available metering tools. So one might say "I went for xyz LUFS" but does he/she mean average, maximum, integrated, etc?

DR-Metering ("Dynamic Range" metering, or in reality "crest factor measurement", first created by Friedemann Tischmeyer/Algorithmix and ported by Brainworx) is also not suitable for the task IMO, as the value varies heavily depending on the density (how dense the production was mixed) of the source material.

Your focus should really be on the basics (in this case: digital meter and VU meter). This might sound absolutely limiting at first. But I (Mister Fox) have been doing this for 10+ years, and I feel not limited at all. In fact, it's the other way around. As I can incorporate hardware or modeled devices in software form as needed/in combination at will, without adjusting anything.





:arrow: The question is now...

How to simplify this/make the rule set more apparent?
Or is this thread enough to cover the fine details?

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by OctopusOnFire » Sat May 27, 2017 4:40 pm

I don't know, I have mixed feelings about this.

On one hand, I understand and mostly agree. With time I've found out that using the least processing possible has way more benefits than the opposite. On the other hand, I can see stuffing the mix bus and different mix groups with plugins as a valid approach as well. I don't mean throwing plugins just because, but purposely doing most of the mix on the busses, knowing how subtle you need to be.

Then again, I never went to any mixing school and I've learnt from this wild jungle of knowledge that is the internet. The first months you take a lot of BS as gospel :shrug:

So on the "how to simplify..." question I'd ask - What kind of plugins/settings are a definite no-no on the mix bus? (Other than limiters, I guess)

And here's another, not that serious one. Why not let people destroy their own mixes so they learn what not to do? :lol:

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by Mister Fox » Sat May 27, 2017 10:45 pm

OctopusOnFire wrote:
Sat May 27, 2017 4:40 pm
On one hand, I understand and mostly agree. With time I've found out that using the least processing possible has way more benefits than the opposite. On the other hand, I can see stuffing the mix bus and different mix groups with plugins as a valid approach as well. I don't mean throwing plugins just because, but purposely doing most of the mix on the busses, knowing how subtle you need to be.
This is the learning factor here. How to (maybe) do things different.

In my case, I only use sub-groups to "group together" certain instruments, to do some broad fixes / volume adjustments / easier automation, maybe stereo field manipulation. Others use sub-groups for the so called "Brauerize technique". And the next guy is using group channels for something completely different (glitching, sidechain compression, etc).

I'm not counting the use of AUX send/return busses for reverb/delay/chorus/flanger/phaser/etc of course. However, most of the time my summing bus looks like one of the 4 examples above.


OctopusOnFire wrote:
Sat May 27, 2017 4:40 pm
Then again, I never went to any mixing school and I've learnt from this wild jungle of knowledge that is the internet. The first months you take a lot of BS as gospel :shrug:
This is what the Mix Challenge is all about - gathering experience, pushing your personal boundaries, trying new things, learning.


OctopusOnFire wrote:
Sat May 27, 2017 4:40 pm
So on the "how to simplify..." question I'd ask - What kind of plugins/settings are a definite no-no on the mix bus? (Other than limiters, I guess)
I gave hints above as to what could be considered "ideal". How everyone handles this topic for themselves, is up to the participants.


OctopusOnFire wrote:
Sat May 27, 2017 4:40 pm
And here's another, not that serious one. Why not let people destroy their own mixes so they learn what not to do? :lol:
This resulted in this thread in the first place... :tu:

And in fact, also the many, many, other threads on known forums like KVR Audio, GearSlutz, etc.
(including the now infamous "The Reason Most ITB mixes don’t Sound as good as Analog mixes" thread on GS).





The thing is, you ultimately only cheat yourself. (IMO and all that)

As mentioned above - you can of course do all the overall sound shaping, compression and stereo manipulation (since the "lines are so thin" and all). Then forward it to another engineer, or another challenge. But you won't do yourself any favors IMO. Maybe the material has been damaged-beyond-repair in the process, maybe the carefully crafted transients have been squashed to bits, maybe you overdid it with the saturation modules (too hot on the input side), there is some weird stereo panning going on, the track is too loud to begin with (therefore it will lack transients and it's dynamic feel), etc. You never know. Basically, you try to be "competitive".

On the other hand, the mastering engineer then has to work with that particular material. However, there is a certain limit as to what you can still do with the material that has been given to you. See like it a hairstylist - you can always cut things shorter, but not longer again.


There is this... "notion" in this realm / industry that you have to(!) do everything yourself, that the distinct lines don't exist anymore and you "just have to make sh*t fat and loud, render as MP3, release to the masses" and then you made a hit record. I can honestly not agree with that.

I always defended the position that you should focus on what you're really good at. Unless you're experimenting and try to learn new things (to get acquainted with this area, or enhance your already existing skills) - which is acceptable of course. However, the notion is to cover "everything" - meaning: songwriting, producing, mixing and mastering. But the reality is, that there is no pressure to do everything all in one swoop.

I've seen musicians where this did more harm than good (and resulted in a very strange overall sound, or messed up mix) - so to me, this is doing more harm than good (again, IMO and all that). Just... work in the area you're really great at. Sound design, songwriting, producing, mixing or mastering. Ignore what magazines, videos on Youtube and co or "the internet says". Open your mind, broaden your horizon.

It's hard to step out of the comfort zone and "limit" yourself again. I've been there myself - and at some point, it was so liberating! And this is why I have repeat customers these days - they focus on what they're good at (producing/songwriting), and involve me in the area where my skill-set exceeds theirs (mixing and/or mastering).




And "this" is what the Mix Challenge (as a whole) tries to pass on...




Two famous movie quotes that might fit to this discussion.
How you interpret them in this context, is up to you...

"This is a sparring program, similar to the programmed reality of the Matrix. It has the same basic rules, rules like gravity. What you must learn is that these rules are no different than the rules of a computer system. Some of them can be bent. Others can be broken."
- Morpheus, The Matrix (1999)

"The code is more what you'd call 'guidelines' than actual rules"
- Hector Barbossa, Pirates of the Caribbean: Curse of the Black Pearl

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by OctopusOnFire » Mon May 29, 2017 12:49 pm

I just read that GS thread (just the 1st post) and it describes one of the most recent and helpful "wow moments" I've had. 70% of what a track needs to work in the mix is proper gain staging, and I could say 90% but I want to be conservative. If only a trim can't fix it, then reach for eq, compression, distortion, whatever.

Right now my mixes live in the yellow area of the meter, and the mix bus usually peaks under -10 dBFS, still I can't help but think "hm... maybe if I don't turn it up 5 dB it won't stand out among the rest of the candidates". It's almost an irrational fear.
I just wanted to say I've been learning for over 2 years and I still find it very, very hard to wrap my head around the whole mixing vs. mastering issue. I wish I had it clear as day. I wish I could clearly identify the point where I've stopped mixing and started mastering, so I could aim for it when mixing, not further. If I could learn only one thing from this forum, that'd be the one.

I'm curious if anyone knows about any site where you can listen to a songs' mix and master to compare? Preferably commercial or at least mildly successful bands.

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by Mister Fox » Tue May 30, 2017 5:20 am

I am not aware of any comparison sites, sadly. So no help in that direction I'm afraid.



What I can say however, is that "mixing" and "mastering" is fairly easy to separate. At least for me it is.

Mixing is basically anything that you do in a multi-track session. This is what you currently do already. You try to mix several tracks in such a way, that they work as a "whole". The sum of all things is what is important in this step. You can go nuts here with automation, filter usage, creative effect module usage, etc.



Mastering is then for adding the final touches, maybe even export it in a specific format for mass distribution.

You either do this via a couple of subgroups (that can be adjusted as needed, though I always disliked this), or merely a stereo mixdown. In this editing step, you take another look at the frequency spectrum, listen if there are frequencies that stand out or need to be "more featured". You basically add "fairy dust", or remove the "veil" that lies on the mixdown. Additional to that, maybe you want to "compact" the signal a bit (think "Glue Effect"), push the signal towards a suitable loudness, maybe further manipulate the stereo field (make it properly mono compatible up to a certain frequency, spread out the stereo field just a slight bit more), add some proper limiting of rogue peaks.



Limiting yourself with the tool usage of the summing bus does help understand the distinct lines.



Regarding suitable work levels and color codes.
I wrote plenty of comments/articles about this over on KVR Audio in these KVR marks.

But for completeness sake - I'm using the following color codes for the meters in Cubase:
Green: -inf to -18dBFS // Yellow: -18dBFS to -6dBFS // Red: -6dBFS to +inf
I'm pretty sure that you can setup similar in other hosts as well

Since I'm using a VU and Digital Meter combo during mixing, I always know where my signal strengths reside at. Bass intensive material hovers around 0VU = -18dBFS, transient heavy material doesn't exceed -6dBFS per channel. If I mixed right, the signal strength on the summing bus can hover between -3 VU and +3 VU, while the maximum signal strength (dBFS) can reach up until -3dBFS easily. If I used a lot of transient designers.

But this delves deeper into the topic "Gain Staging"... something you already dipped your toes into with the thread over on GS.

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by HerbFelho » Wed May 31, 2017 9:44 am

Well, I guess then I will try to see it as another challenge to craft mixes only with these options on the mixbus that you mentioned.
And indeed, if someone´s not able to deliver good mixes with only these plugins then something´s wrong anyway.

Altough like I mentioned in a previous post my opinion on distinction between mixing and mastering is a bit different. Times are a changing and I guess the vast majority of engineers is in the box these days and do and simply deliver "finished" songs for their clients, also on grounds of limited budgets all-around, so why not deal with that? Also, you give the impression that using multiple plugins on the master bus always provides a kind of advantage in a mix challenge which you want to avoid. Don´t worry about that, a good engineer will craft a good mix no matter if one or ten plugins on the mixbus, a not so good one will deliver not quite so good mixes and will make it even worse with every additional plugin slapped on the master, seen this a thousand times.

Like i said the only "unfair" advantage in a challenge like that could be the loudness problem, since "louder is better" is a fact, and if mixes with different average loudness is delivered to the artist, which may not be aware of this problem, this will influence his decision massively. So for me I will try to adapt to the loudness guidelines that you provide as close as possible.

Just my personal view, of course I accept avery rule you state here.
I also completely agree learning and growing as mix enigneers should be number one here for anybody.
Love this site and thanks for the hard work you put into it!

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by marc clement » Mon Aug 21, 2017 8:07 pm

Hi All,
I`ve just submitted for MC35 and had to turn down my mix to fall within the guidelines, which is fine but oh boy was it a difficult decision.
I work ITB on a principle of -18 peak in. I use parallel comp through out my mixes and have a pretty much static Stereo bus chain (which I mix into) of SSl comp, Puiltec eq, MS comp (51% wet ) all usually just tipping the meter, tape emulation and then a true peak limiter at -2 which occasionally knocks at couple of db off here and there. I also use the "rear bus" technique.
I have fixed monitoring levels and my mixes always seem to come out about -13 rms with a similar LUFS.

I`m kinda of the opinion that you should leave as little as possible to the mastering engineer and we should be delivering as near a finished product as possible. It is a learning curve and its great that we can all share knowledge and experiences.
I`m currently keeping an eye on Spotify as they are regularly updating their recommended levels which are -14LUFS which I believe is similar to RMS on a balanced mix. It would be good if Mix Challenge just set a limit of say -14 rms and thats that. In general its good to see an end to the Loudness War and we are now heading back towards a more dynamic listening experience. Digital is great but it just gets abused. !!

Marc

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by Mister Fox » Mon Aug 21, 2017 9:45 pm

Just for understanding purposes:

1) you set your VU's to -18dBFS = 0VU? -18dBFS max peak sounds really, really low (you're constantly underdriving your equipment, incl. "analog emulation" plugins)

2) moderate summing bus treatment should be fine, as long as it's not overdone (you're using two comps, plus EQ, plus tape saturation/compression and another peak limiter!)


I don't want to set an upper limit. The goal of the Mix(ing) Challenge is to learn how to mix in a best-as-possible way, without already pre-mastering.

Also see these two threads:
Q&A - Mix Challenge - rule set and reference/target levels (split from MC35)
Taking a new route - expanding the Mix Challenge

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by marc clement » Mon Aug 21, 2017 10:21 pm

Hi Mister Fox
1) you set your VU's to -18dBFS = 0VU? -18dBFS max peak sounds really, really low (you're constantly underdriving your equipment, incl. "analog emulation" plugins)

Yes sorry , I was unclear . When recording I dont want peaks much above -15, drum s are gonna be a bit more as -18dbfs is equivalent to analogue zero. My Vu are calibrated to 0dbfs, so there is no problem with the analogue emulations.


2) moderate summing bus treatment should be fine, as long as it's not overdone (you're using two comps, plus EQ, plus tape saturation/compression and another peak limiter!)

The SSl knocks about 1db off . The Millennium in M/S as I just like the shape it gives. Its not actually compressing. I am only using one limiter , a true peak limiter, set at -2 only to prevent any overs from downstream file compression e.g. mp3

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Re: Mix Challenge - Rules and Guidelines Addendum: Summing Bus Treatment

Post by Mister Fox » Mon Aug 21, 2017 10:39 pm

Apologies for editing your post, I just added the "quote" command to make things easier to read.
marc clement wrote:
Mon Aug 21, 2017 10:21 pm
Yes sorry , I was unclear . When recording I dont want peaks much above -15, drum s are gonna be a bit more as -18dbfs is equivalent to analogue zero. My Vu are calibrated to 0dbfs.
So you're using a VU (300ms) also as peak meter?
Sorry - but your values are irritating.

A VU setup to to 0dBFS would mean that the VU shows -10VU to -5VU or something if a signal at -15dBFS max peak (transient heavy material) would come in. This is why I (as Audio Engineer) insist on properly naming what values you mean. However... if you use your mixing engine this way... you either under drive/overdrive your mix environment, and then I understand why you use several compressors/limiters.

This topic however drifts off into "gain staging schemes".


marc clement wrote:
Mon Aug 21, 2017 10:21 pm
The SSl knocks about 1db off . The Millennium in M/S as I just like the shape it gives. Its not actually compressing. I am only using one limiter , a true peak limiter, set at -2 only to prevent any overs from downstream file compression e.g. MP3
If you're getting -14LUFS ILk as final result, and you don't have any rogue max digital peaks, you'll barely reach that value with 320kbit. So you're save from clipping either way.


If you have to turn your mix down on the summing bus, maybe it's time to overthink your mixing technique in general?

Maybe take note of this thread again (many more cross references in there):
Q&A - Mix Challenge - rule set and reference/target levels (split from MC35)

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