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Monday, October 15, 2018

#Musicproduction: Gain Staging Explained

Hitting the “gain staging” wall is often a lesson that everyone remembers.Mine is in 2005: I used to be finishing a youtube video scoring project at Musicians Institute and I used to be re-scoring a clip for Hellboy, within my final. I had put together many electronic sounds, an online orchestra with percussion... it became a huge session. I reached a point where things sound the way in which I like: “I simply bring inside the electronic percussions and We are done”, I think.. overly-excited to be able to go home early, that day.
When I brought those additional tracks in, my double basses disappeared. "Mh.. let's bring them up.. now the cellos are weak.. If only I had put together a bit more timpani.. what's that grinding sound? Ah! My mix buss is clipping. I'll bring its input down.. now We are no more clipping nevertheless the mix sounds off-balance, lifeless and dull."
My concept of going home early started vanishing in front of my eyes, I really didn't know how to get back to that “ok”-sounding mix, and inside the distance I began hearing the sad sound on the viola solo. It had been clear it couldn't have any worse.
The challenge - that day - was partly due to my lack of edcuation of gain staging.

What Is Gain Staging?

To me, gain staging is the tactic of consciously managing the gain of several tracks all over the entire path of their described audio signal. Being aware of how gain affects your audio signal along with your end result is often a basic, yet fantastic (and often overlooked) skill to acquire in recording, mixing and mastering.
Within a Digital Audio Workstation (DAW), the headroom of our session will depend on the degree of bits available. Since waveforms are explained by numbers, those bits determine the maximum value for your waveform the system can describe. The higher the gain, the louder the waveform, the more bits are utilized, the higher the number. Once the many bits are utilized, the device can no more describe the waveform, a red light turns onto indicate that you are “clipping” plus the waveform you're recording/hearing will have problems with unwanted distortion.
In the analog domain (think on the tape machine) things are all different. The analog device carries a sweet-spot (0 VU on its meter, usually) of operation and tone and color change when hitting it lower or higher than that. In case you continue higher with the help of gain, you might reach a point where things will sound clearly distorted, since the device cannot capture your intended signal which consists of “analog” counterpart (e.g. electric to magnetic, for a tape machine).
Without going too deep into headroom, bits (floating-point and so on in your case witty heads behind the classroom), it's clear that gain staging goes to improve our using the available headroom:
  • we can prevent hitting all of the scale value and get away from distortion/clipping
  • we are able to decide the intensity for hitting an analog (or virtual analog) device to find the color/tone that we'd like
As well as got until you wish the drums becoming a bit louder, but:
  • you make drums louder: the mix distorts and sounds terrible
  • you make all the others softer: the mix lacks life, sounds completely different and requires re-doing?

The Kick/Snare Pivot Trick

To do so, through the years, I've developed holistic approach that usually work each of the time. I set my bass drum and snare drum levels heading to just some of the “yellow” area in Pro Tools - which similar is just about -24 dBfs RMS within the meter (peaks hitting from -6 to -3 dBfs). You possibly can take this review to your DAW and construct your visual reference.
To be a the second step I set my monitoring volume to a cosy amount. I have got a stepped switchin my monitoring controller so I will usually place it at the right level without even playing the music. Once set, I propose you keep it there and usually not touch it, or at best make hard work to grow it back to the first position any time you touch it.
Should your monitors output enough volume, you will cease lured to push the volume within your tracks to ensure that things being heard. We're mixing! The main objective here is to “mix” the tracks, there's little fascination with the absolute volume level from the actual track. That's why we created mastering engineers!
After all this I will start bringing in all the aspects of the mix as well as set general volumes, even though the bass drum and snare drum are playing (always with those!). Important: I really don't set the track volume while using the volume fader of this channel! I keep that at zero and workout a “trim” at the beginning of the channel, instead.
A “trim” is an over-all volume knob or fader whose purpose is merely to get a new gain of the signal. By doing this I reserve my main track fader for automation and additional changes after the channel processing. For the reason that resolution on that fader is higher when more detailed zero, keeping it around unity gain value is an effective way to implement its maximum resolution.
If toddler make use of a plug-in, a sensible way to take action should be to change the gain of your clip itself. Every DAW these days can do it and a fantastic way to keep your session neat and sounding “right” with the get-go.
By following this technique, things will fall into position according on their loudness comparison to its kick and snare just as soon as many of the tracks are in.. evaluate the meter of your mix buss: it are going to be around -18 to -12 dBfs RMS. Plenty of headroom just in case you need to take somebody up a dB or two being heard. Your mix will breath better, your automation will sound better and you will stay well away from the dreaded red light of clipping.
Well, there's a difference.

Using Buses As An Additional Staging Point

Grouping separate tracks together by routing the theifs to a bus is an easy way to control the entire sound of their group.Drums, bass, guitars, keys, vocals and effects all go to split up busses, during my example. By doing this I will:
  • monitor their individual level
  • apply processing to the group
  • trim the quantity of each and every buss, if you need to, 100% transparently (thanks, digital!)
As you have seen, I needed less vocals and a tad bit more effects. One quick method it had been move the faders about the busses.. sometimes I even put a fresh Trim plug-in on those busses, input the values and then reset the faders to zero.

Gain Staging For Analog Outboard And Plug-Ins

You should know that gain staging is vital even when simply usingan analog or digital device (especially after they make believe you emulate analog!). Beware: it's mostly subtle, however it is there!
Every example has a new volume of “current” flowing in the actual EQ circuitry. This makes the EQ sound slightly different from, for example: IN+12 OUT-12 (lots of gain pushing into the EQ) and IN-12 OUT+12.
Are plug-ins different? Incredibly more the same goes with the UAD 550A plug-in.
As you're able tell, there's still some difference, although even perhaps less space-consuming than in the hardware version. Knowing these subtleties will allow you to find out the particular level at each bit of analog hardware wants to be struck for a specific sound!
Let's go back to my busses and let's put a compressor plug-in on all of them. I've used the Brainworx Townhouse Compressor on every one of them, with various settings for each bus. This amazing item of hardware has a great story and it would be a goal to get six of these questions rack, so since "one can dream" I made my own personal, virtual Townhouse rack (added geeky-ness: the cables towards the end are a true picture of the back of among the list of racks, only at Fuseroom).
First off, let's send a 100 Hz sine wave through it. You will observe the yellow line being the normal sine.Now check what develops when we push gain in the compressor while engaged: the harmonic distortion of your emulation re-creates the adjustments that, supposedly, the hardware introduces. Therefore, commencing this plug-in louder or softer won't get a new compression amount (hence the tone) but also the harmonic distortion placed on the track (the "tone of the therapy lamp"). I told you get staging was important!
It gets more interesting: the output knob of your plug-in has a solid of the company's own and isn't linear.Think about the two pictures comparing a +13.5dB output gain done that has a transparent Trim plug-in in Pro Tools or done together with the output knob of your Townhouse compressor (yellow vs violet). Therefore even that output gain knob is generating some color/tone.
This becomes apparent whenever we have fun playing the song with various trim values before those compressors. By trimming many of the buses down of the same amount (and then compensating) we're hitting the compressor differently, getting different variety of compression and for that reason a new tone and "glue" of your mix.

Gain Staging On Your Mix Buss

At the end of your chain can be your mix buss and activities like that could possibly get affected on your gain staging. I always enjoy having control in my ways IN and OUT of their mix buss. In Pro Tools it's possible with Master Channels (as you observe on this picture, the red ones around the green Mix Buss channel are respectively just how IN and OUT). The main thing should be to have something completely transparent that handles the quantity of gain interior and exterior that bus.
Essentially, I loaded a generic mix buss chain that I love, from my template. What I am using will not be important, but here goes:
  • UAD Shadow Hills Mastering Compressor
  • Slate Digital FG-Red Compressor
  • UAD K-Stereo
  • UAD Precision Equalizer
  • DUY Valve
  • DUY Tape
  • UAD Precision Maximizer
  • UAD Precision Limiter
  • UAD Neve 88RS Channel Strip
Let's send a 1 kHz sine wave tone that slowly creeps in profit from -30 dBfs to -1 dBfs. The initial pass are going to be while using Mix Buss completely bypassed plus the second you are going to be while using Mix Buss engaged.
In the event you compare the 2 main, some may be perfectly linear (as to be anticipated at a simple sine sweep in digital) but one other is not. The fun thing is that - while using Mix Buss engaged - the loudness meter demonstrates one more gain is lower than the original for signals a lesser amount than (approximately) -16dBfs) and higher for signals above it, getting higher in difference the harder we approach 0dBfs.
Why is that? In theory, since we've compressors on the mix buss, we might expect the opposite. Compressors will commence compressing as soon as the Mix Buss is engaged, so the linear sine wave sweep should end up being the louder one. But this is not the case. The real reason for this is the harmonic distortion that is certainly created by each of the plug-ins, especially the Valve/Tape emulation and the UAD Maximizer, winding up with the 88RS channel strip that I put there used only for flavour (it does “something” for the sound, regardless of whether the channel strip remains completely flat).
During this final case, understanding how the gain staging works from plug-in to plug-in inside the chain and on the mix buss “like a whole” will support you in finding out the sweet spot and tune one further processing bus for top result.
Proper knowledge of gain staging makes it simple to combine directly into any processor, which is one area We do on a regular basis in hybrid mixing (and also in those rare cases of mixing entirely ITB). This process makes my mixes easier, faster and effortlessthan the pain of going by way of a merely “transparent” virtual desk around my DAW. I know most of you prefer to maintain the mix buss clean until the end with the mixing.. to each and every his/her own!

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