Mastering Compression Settings Overview
In this video, the chapters are in no particular order, but we will be discussing various forms
of compression in-depth, as well as introduce some useful techniques you can use when mastering.
We’ll cover how to glue a mix together with compression, as well as how to very transparently
compress, to get a cohesive and colorful sound or solely control dynamics respectively.
Then we’ll cover how compression can alter the frequency response, and how we can use
a MB compressor to mimic how our ears compress in order to create natural-sounding compression.
Next, we’ll discuss New York-style parallel compression and how it can be used creatively
to affect a master in a way most regular processors can’t - before we discuss the benefits of
simultaneous expansion and compression, and how compressors can be used to alter a master’s
stereo width.
Next, we’ll cover how to bring quieter details of a master to the forefront without the need
for aggressive peak-down compression.
Lastly, we’ll cover how to de-ess during a mastering session to attenuate sibilance,
but avoid compressing unrelated frequencies, how to reduce resonances with a couple of
different processors, and finally how to use dynamic EQ to attenuate out of key frequencies.
I’m guessing you won’t want to use all of these types of compression, but at least
1 will definitely be helpful for your style of mastering, so stick around to learn about
each type and technique.
Master Compression to Glue Mix
One of the most popular ways to introduce compression when mastering is as a way to
glue together the sound.
Glue compression is created by setting a longer release time so that multiple transients are
compressed collectively.
The benefit is that the master sounds cohesive, but we need to be careful, since affecting
multiple transients can affect the perceived timing of the track.
To do this the right way, we need to time our compression with the BPM of the track.
So if our BPM is 140, we can divide 60000 by 140 - the result is 1 quarter note in millisecond;
In this example, 429 milliseconds is 1 quarter note.
Then I can multiply this number by 4 to get 1 whole note, then subtractive the value of
our attack time, and use this value as the release time.
For the sake of understanding this better, let’s say we use a release time that is
not in time with our track, say 1 second.
Then whenever the signal returns to unity, it’ll sound amplified relative to what was
just attenuated.
In other words, it’ll serve a somewhat similar purpose to a transient - if this return to
unity is out of time with the track, we can severely mess up the perceived dynamics and
subsequent timing of the master.
In addition to timing our release time, we can use a compressor that imparts a specific
tone to the signal - this means a compressor that introduces harmonics and maybe some subtle
equalization.
For this reason, maybe engineers like to use variable compressors, more commonly called
Vari-mu compressors.
I’ll use this Pulsar Vari-mu plugin to demonstrate the idea, but Klanghelm offers a great free
option if you’re interested.
Let’s take a listen to glue compression being introduced with a Vari-mu type compressor,
and with the release set to be in time with the track.
Creating Transparent Mastering Compression
Sometimes when introducing compression, you don’t want to create a colorful sound - or
even be able to tell that the compressor is there at all.
When this is the case, we’ll want to use clean, transparent compressors, and in-time
settings that return the signal to unity quickly but are set in a way that doesn’t result
in distortion.
Let’s use this free plugin - Tokyo Dawn Lab’s Kotelnikov, to introduce transparent
compression.
Notice that with it, we can introduce both peak down and RMS detection - RMS or root-mean-square
detection will average the incoming signal to measure an average loudness.
It’ll result in more transparent compression; however, it may let loud peaks through, so
we may want to find a good balance between peak and RMS detection, and pay attention
to when the signal is being attenuated.
We’ll want to set an attack time that’s no quicker than 10ms, and a release no quicker
than 50ms - the reason being, if we set quicker times, we can cut into a transient, in turn
causing harmonic distortion.
This is great to have the transients stick out, but it’s not useful for clean-sounding
compression.
Additionally, I’ll set the release to be in time with the track, similar to last chapter,
but instead of a whole note, I’ll use a 1/16th note.
To find that take 60000 and divide it by the BPM, and then divide by 4.
Lastly, we’ll want to set the stereo sensitivity toward the center or mid-image - this way
we’re detecting and affecting where the majority of the master’s energy is.
Be sure to carefully set your threshold and use a low ratio to ensure we don’t compress
more than 1.5dB.
Let’s listen to this compressor being used, and notice how it cleanly attenuates the master.
Using MB Compression as EQ
Multi-band compression is super useful if we want to control a specific bandwidth of
frequencies - it can also be less noticeable than regular stereo compression for this reason.
All of the concepts we’ve discussed in the last 2 chapters still apply - like timing
the release to be in time with the BPM and avoiding super quick attack and release times
to avoid distortion.
The main difference is that we can use fast attack and release times on the highest frequencies
- since the distortion typically caused by these settings only occurs to low frequencies.
The main idea I want to introduce though is that compressing specific frequencies both
controls dynamics and causes equalization.
So let’s say the track is sounding muddy and I’m having trouble hearing the vocals
- I could center the compression on 250Hz. and attenuate by 1 to 2 dB.
This will attenuate the frequency range like an EQ but do so dynamically, instead of statically.
This a great way to alter the frequency response of a master, but only when a particular range
becomes too loud.
Or let’s say the reverb is covering up the vocal too much, I could dynamically attenuate
2-5kHz on the side image so that the mid-image vocal cuts through whenever it’s present.
Also, I’ll use this FF-MB, but a good free alternative is TDR NOVA.
Let’s take a listen to MB compression being used in this way, and notice how it shapes
the frequency response.
Recreating How Our Ears Compress Sound
While we’re on the topic of frequency-specific compression, let’s cover how we can use
MB compression to mimic how our ears naturally compress sounds that are too loud.
I covered this in our last video on vocals but let's look at it one more time.
In short, our ears compress frequencies below 1000Hz, whenever the sound gets too loud - this
attenuation is between 1-20dB, depending on how loud the sound is.
Also, the 2 structures that cause this can’t move instantly to attenuate the sound - it
takes about 40ms for them to tense up or contract, and they stay contracted for about 150ms.
With that in mind, we can use a MB compressor and attenuate frequencies below 1000Hz by
a couple of dB.
We’ll set the attack to 40ms and the release to 150ms to mimic the response of the 2 ear
structures, and if available, use a softer knee to cause gradual compression.
Be sure to avoid lookahead and any other unrelated settings.
Let’s take a listen, and like last chapter, you can use TDR NOVA as a free alternative
to this plugin.
New York Style Mastering Compression
New York Style compression is a combination of parallel compression and EQ.
To create it we’ll need to set up a send and corresponding auxiliary track from our
channel track.
On it, we’ll insert a compressor and an EQ.
We can use compression that glues the signal together or transparent settings but with
a great overall amount of attenuation - since we’ll be blending this effect in with the
auxiliary track’s fader, we can be more aggressive with our settings.
Then, we’ll insert our EQ - we could use a fully parametric one to really control what
part of the compressed signal gets amplified, or we could use something more stylistic like
a Pultec EQ to shape the sound - if available, be sure to use a linear phase setting for
the EQ to avoid phase cancellation between this track and the original channel.
With the EQ, we could amplify the kick, and the vocal range, and maybe some of the highs
to accentuate important ranges - but what you amplify is up to you.
If you want to get even more of the sound of the compressor, we could insert an EQ before
it, and drive frequencies into it.
This way the compressor is having to work harder on those ranges, in turn causing compression
on those frequencies to be more apparent.
This method both controls dynamics gives you the option to equalize the compression and
makes it easier to automate this compression by altering the aux track’s channel fader.
I’ve been using this FF-Pro C2, but let’s use this free SSL emulation by Analog Obsession
and create parallel compression with a lot of character.
I’ll equalize both before and after compression to emphasize important ranges and then blend
in the effect.
Let’s take a listen, and notice how the master sounds fuller, and how the amplified
frequencies stick out a bit more.
Omnipressor Expansion and Compression
The Omnipressor is a unique compressor - it allows you to set levels for compression and
expansion simultaneously, resulting in signal attenuation whenever the signal goes above
the threshold, and expansion whenever the signal falls below the threshold.
As a result, the signal stays within a dynamic range, resulting in louder parts becoming
quieter, and quieter parts becoming louder.
Although this effect is typically used for mixing, it can be used to great effect when
mastering.
If we limit the expansion and compression ranges to 1dB, set the function or ratio near
the middle, and very carefully set our threshold, we can achieve a dynamically controlled, and
surprisingly loud master without unwanted artifacts.
I find that this effect works great before limiting when I want the signal louder, but
I don’t want to resort to heavy amounts of attenuation to achieve it.
Although you could use 2-instances of a free compressor like MCompressor by Melda Audio
to achieve compression and then expansion, the routing is different than this plugin,
so unfortunately I don’t know of a free alternative that matches this plugin exactly.
Let’s take a listen to this plugin used with subtle settings, and notice how it makes
the track louder, dynamically controlled, and makes quieter details easier to hear.
Mastering Compression for Stereo Expansion
We touched on this concept in chapter 4 when we used MB compression on our side image,
but let’s go into more detail about affecting a master’s stereo width with compression.
If we use a compressor that’s capable of mid-side compression, we can introduce more
compression to the mid image to cause stereo expansion - whenever the mid image is attenuated,
the side image will sound louder relative to the mid or centered image.
Usually, I want to attenuate the mid-image by .5 to 1.5dB, and avoid things like make-up
gain, since that would negate the stereo expansion aspect.
Some plugins that work well for this include Presswerk by Uhi, Weiss Maximizer if you select
the Wide algorithm and the more comprehensive DS1 compressor, and the FF-Pro MB if you want
the attenuation to be frequency specific.
A great free option though is the MCompressor by Melda Audio - if we open the toolbar section,
we can change the routing from stereo to mid and side, or in this case just the mid image.
Ultimately, this is one of my favorite ways to compress a master, since it controls dynamics,
and results in very natural-sounding stereo expansion.
Let’s take a listen, with more aggressive settings than usual, and notice how the master
sounds wider whenever the mid-image is attenuated.
Why Upward Compression is so Useful So far, all of the compression types we’ve
covered cause attenuation from the peaks down, or from an averaged loudness down in the case
of RMS compression.
But one of the most useful forms of compression in my opinion is upward compression.
In the case of the Waves MV2 - it can measure quieter parts of the signal, control the dynamics
of that quieter section, and then amplify it.
This results in a controlled dynamic range, without the need for attenuating peaks.
More importantly, it amplifies quieter details and makes the overall master sound fuller
and more forward.
Another option is the Sonnox Oxford Inflator - it works a little differently by prioritizing
aspects of the digital signal with more 0s than 1s (at least that’s how it’s described
in the manual) and then amplifying these parts of the signal, and adding harmonics to fill
out the sound.
Alternatively, you could use the free MCompressor and use the custom shape setting to amplify
the signal whenever it falls below the threshold - the concept is similar, but the final sound
will be a little different.
One more free option is OTT by Xfer records which offers frequency-specific maximization,
but you’ll need to use incredibly subtle settings with this one since it’s a really
aggressive effect.
Let’s take a listen to the effect with my personal favorite option, the Sonnox Limiter’s
enhance function, and notice how we’re not attenuating the peaks, however, the details
of the master are greatly increased, as is the overall loudness.
Upward Compression on Mid Hz.
Now that we understand upward compression, let’s see how it can be used creatively.
If we use upward compression in a form of New York-style parallel compression, we can
greatly emphasize a particular range of frequencies.
To do this, I’ll set up a send from the channel track, and on the corresponding aux
track first, insert a linear phase EQ.
With it, I’ll isolate the signal to the mid frequencies by using a high-pass and low-pass
filter.
Where you center these filters is up to you, but I’ll set mine to 400Hz and 4kHz respectively.
Then, I’ll insert an upward compressor or maximizer - in this case, I’ll use the Sonnox
Inflator, but you can use an of the options we just discussed in the last chapter.
With the inflator, I’ll set its effect to 100% and then blend in the upward processed
mid frequencies with my original signal.
With this setup, we reduced the dynamics of the mid-frequency range, greatly increased
aspects that would’ve otherwise been masked, and then dialed in the effect until the overall
sound is balanced.
Like chapter 6, we have the option to emphasize frequencies into the processor if we want
them to be more apparent.
So I’ll create a bell around my vocal’s clarity range around 2kHz, and also amplify
the side image around the 500Hz.
This is just what I thought sounded best for this particular track, but use your ear and
emphasize and frequencies you want more of.
Let’s take a listen and notice how the mid frequencies are present, and how the overall
master sounds fuller and more impressive.
De-essing During Mastering
Although de-essing isn’t always needed when mastering, it does serve an important role
when it is needed.
Finding the right settings can be challenging so let’s look into it.
We’ll need to isolate the compression to the range of sibilant frequencies, usually
between 5-8kHz, but you’ll need to listen to find these, or listen and observe the frequency
spectrum.
After we’ve isolated the attenuation to the correct range, we’ll need to ensure
that attenuation only occurs whenever a sibilant occurs.
If we don’t set the threshold correctly, it’s really easy to attenuate unrelated
aspects of the signal, like cymbals or other high frequencies.
Doing this correctly comes down to listening carefully, and observing the attenuation,
and seeing if it pairs up with when sibilance occurs, or if it’s attenuating at an unrelated
part of the signal.
I’ll use this Weiss de-esser, but you could use a MB compressor.
If you want a free option, T-De-Esser is a good alternative, and I would also recommend
Sibilance 4 by Toneboosters, which offers a lot of control and is really affordable.
Let’s take a listen and pay attention to how attenuation only occurs whenever sibilance
is present.
Resonance Reduction with MB Compressor
Although resonance reduction is usually thought of as a form of equalization, it’s really
a multi-band compressor with a preset threshold that determines when to attenuate various
frequencies.
It’s an incredibly useful tool when trying to create a balanced master - so let’s look
at some good settings.
I’ll use this Soothe 2 plugin, and to make it easy, select the Balanced to the Grammy
Awards setting - which measures the mid and side separately to apply compression when
needed.
From here, we can adjust the pre-emphasis EQ bands as needed, to attenuate aspects of
the master that are too prevalent.
The low mids are usually a trouble area - the same could be said about the sibilance range.
That said you’ll have to use your ears.
Lastly, if you use this plugin, be sure to use higher quality settings to reduce phase
cancellation, and to dial in the effect with the mix dial.
Although I don’t know of a free alternative, Smooth Operator by Baby Audio is a good affordable
option.
Let’s take a listen, and notice how the master sounds balanced.
Out-of-key Subtractive Dynamic EQ
In chapter 4 we discussed how MB compression can change the frequency response, and in
a way, be used as equalization.
If we have a dynamic EQ, we can pinpoint which frequencies we compress - in this case, we'll
attenuate out of key frequencies.
This results in a more musical sound since desirable in-key frequencies become louder
relative to out-of-key frequencies.
To find these frequencies, we can use this free online Tunebat analyzer, and once we
know the key, look up which frequencies are in and out of key.
From there, we can use this Pro-Q 3’s piano roll to snap the band’s center frequency
to exact notes, but if you don’t have this EQ, you can look up the exact frequencies
of notes, and center bands on those.
Lastly, we’ll enable dynamics for each band and set the threshold as needed.
We’re aiming for between .5 to 1dB of attenuation, and it’s best to set a narrow Q value so
that the majority of the attenuation occurs on the out-of-key note.
Let’s take a listen, and notice how the track sounds more balanced, and a little more
musical.
Thanks for watching, and be sure to check out the link in the description for a free
mastered sample of your mix.