Hello my name is Jonathan Wyner, thank you
for joining me for another episode of Are You listening? Feel free to go to the iZotope.com website
there are lots of educational materials there and you can download a copy of Ozone. For this segment work to be talking about
compression. Compression’s hard. It is one of the hardest things to learn to
work with. It took me quite a while before I felt like
I had a handle on hearing it and using it. When you're hearing compression very often
you're hearing the absence of something as opposed to the presence of something and so
just takes a little bit of training and time. You should understand that compression doesn't
play a role in every mastering session not every song needs it. The best gain control in the context of music
production is usually that that takes place using a fader; gain riding is awesome it's
very high fidelity there's no artifacts there's no color from it and then compressing and
controlling the dynamics and dynamicism of elements within your mix is really the best
way to go. Most engineers that I've worked with who has
been working at their craft for a long period of time and spend most of their time compressing
if they compress in the channel or maybe on a sub-bus for individual instruments there
are exceptions to this I know Sylvia Massy is a huge proponent of setting up her control
on the mix bus and mixing to it so there's no right way to do it or wrong way to do it
but even in that case you've got the compressor on the mix bus and you can mix into it . In mastering everything's fully baked so if
we try to use a heavy hand with compression in one section of a song chances are it won't
work as well in the next. Having said that sometimes we do need to use
compression to help us manage in a subtle way the relationship between elements in a
mix, maybe got a little bit more punch or smooth out the sound or reconcile differences
from section to section. Sometimes in mastering we even just doing
game riding going for one second to the next so here's some thoughts and ideas about using
compression in mastering. Compressor are different from limiters in
that they let you work with longer timeframes. Limiters a really a safety to prevent you
from over modulating. Compressors because they will, the release
time of the compressor might be fractions of a second rather than milliseconds if you
will, they map better to musical signals anything with sustain anything that's got a note to
it. And so if you find yourself needing to smooth
out the musical dynamics in a track a compressor is a much better choice for that in the applies
to mixing as well as mastering. Common myth number 624.9 compressors: don't
make anything louder compressors turn things down. The common misconception that people think
that in order to make a track loud you need to squash it... it does make sense that if
you restrict dynamics of a signal you might create more headroom so you can turn the whole
thing up but really what you're doing is you're turning it down so that then you can turn
it up after the fact. It's important to keep that in mind, equally
important is to understand that compressors will rob a signal of some early harmonics. And early harmonics often are positioned in
the spectrum in a place where our ears are more sensitive so a lot of harmonic content
between 1000 and 3000 or 4000 hertz will give you more loudness according to our perception
when you compress you probably lose a little bit of that information unless you use a really
fast release time or some unusual compressor circuit that adds distortion. A compressor’s is good for adding punch
for adding glue all of these things that I'll try to give some audible definitions to in
some sound examples but it's not really the thing that makes something loud. When I think about a compressor I think about
the way it helps you shape the envelope of a signal the adsr attack decay sustain release
envelope. In some ways compressor are like transient
shapers; they allow you to modify the relationship in the sharpness or the the duration or the
energy at the attack of a signal compared to the decay and sustain and to some extent
the release. This is something you can certainly do in
the extreme when you're compressing a bass to get more sustain out of every note that
a bass plays in mastering we have to be a little bit more subtle with it. But I think by modifying the ADSR are that's
where we come up with a lot of the effects that were used to describing as a result of
using compressors. The trade-off when using a compressor for
me is between transient and sustain and there's also a trade-off between clarity and density. If you want a record to sound clear chances
are you have to be pretty light-handed with a compressor not use very much, use very low
ratios long attack times so that you don't ruin or diminish the ability to distinguish
between one element and another in a mix. If on the other hand you want a modern pop
sort of wall-of-sound sense to to a recording sometimes a compressor can be really helpful
and just kind of bringing everything together and giving you what some people might call
glue. When people talk about wanting to get a little
bit more punch out of a recording using compression in my mind the way I translate that is they
want a little bit more of the transient to come forward after the the processing. So the recipe that I will use is a compressor
that's got a longer attack time what's the transient come through in the compression
kicks in. I am going to set up a compressor with a fairly
modest ratio actually it's in mastering is kind of average 2:1 use an attack time of
about 40-50 milliseconds and a release time that's on the quick side which in mastering
compression land might be a hundred hundred twenty five milliseconds or so. So hopefully once I'm done applying is compression
you're going to get a little bit more of the thrust the punch of the rhythm track and compared
to anything that sustained in the truck so let's see if I can make that happen. Here you see 50 millisecond attack time hundred
millisecond release ratio of 2:1 on average we got to 2-3 DB of gain reduction I'm going
to start with the Dynamics bypassed and then going to bring them in. So let’s go through that one more time,
dynamics turned off. So hopefully you can understand what's happening
there is the compressor’s is not kicking in until the first 50 milliseconds of the
whatever is triggering the threshold and 50 milliseconds is actually kind of an interesting
number that corresponds to the period of a 20 Hertz signal so that means that anything
that is present at the moment that a transient hits that might cross the threshold will go
through a full cycle before the compressor actually kicks in and interrupts it, so in
my way of thinking there is a relationship between the low-frequency component and the
attack time. As the attack time gets shorter it's going
to start to pull back the low-frequency transient and then as it gets shorter and shorter it
starts to interrupt or influence the the transient shape as one moves higher and higher up the
spectrum. So let me go ahead and demonstrate that I'm
going to play that same section and bring the attack time shorter and shorter and see
if you can hear that the kick drum begins to diminish and the transients in general
start to fold back into the overall mix. And one more time starting with it bypassed. As you play with that more and more I think
you become attuned to that relationship between the rhythm Section and the attack time. The release time will also come into play
to some extent obviously a longer release time will mean that the compression is having
more of a smoothing affect overall and have also an impact on the rhythm section, but
in general the attack time is the thing that that really seems to have the greatest impact. Side chains like opinions everybody's got
one...just trying to be cute here. You've heard people talk about sidechain compression
and most of the people when they say that they are referring to this colloquial idea
having to do with house music or creating some pumping in the low end but the fact of
the matter is every compressor has a side chain and what you feed the sidechain ultimately
has a strong effect or influence on the behavior of the compressor. In the case of sidechaining you might take
a Kick Drum and feed that into a compressor and every time to kick it's the compressor
shoves the signal down it's almost like an automatic gain control circuit or like a ducker. That's a very effective way to get that particular
kind of sound not something that usually happens in mastering that usually happens in mixing. In mastering off and what we want to do with
the side chain is hide the action of the compressor about the compression to not have a sound
so much as we want it to be kind of an invisible or transparent smoother and have a smoothing
effect and the best way to do that is to affect the signal running into the side chain the
most common strategy is using a high pass filter to remove some of the very low frequency
signals from the signal that drives the threshold right that affects the compressor signals
that have more sustain or shorter wavelengths are the things that are actually triggering
the compressor so I'm going to I'm going to exaggerate the effect of this compression
so we really hear at pumping and then I'm going to change the sidechain filter on the
compressor and you'll hear how the behavior of the compressor changes and the compression
effect gets more smooth. So just to help you hear what's going on here
there's enough compression so that every time the kick drum hits the compressor is driving
the the level down and then when it releases obviously you hear the gain ride come back
up pay special attention to the relationship between the kick drum and was functioning
as the snare without the impression they're pretty even in level in the mix when I turn
the compression on the kick drum lower than the snare drum. Give that to you one more time, starting with
it bypassed. You can even hear the gain ride the imprint
of the compression on the vocals as the gain compressor action is taking the level down
and then releasing letting it come back up again. So the way to prevent this from happening
is to employ a sidechain filter there's one in Ozone here where you can run a highpass
at various slopes let me solo the sidechain you can actually hear the sound of the signal
going through the sidechain circuit so remember this isn't the signal we’re compressing
this is the signal that's feeding the sidechain that will actually govern the compressor. If I leave it set just like that you can hear
that the bass and the kick drum just don't have any play at all on the compressor and
the compressor would only be paying attention to the vocal. And maybe the snare drum. So let me turn this sidechain listen function
off and now you can hear the difference in the behavior of the compressor I'm going to
leave the high pass on to start and then I'm going to turn it off so you can hear the A/B
comparison. One more time, start with a high pass on. Hopefully you can hear when the sidechain
goes off every time the kick drum hits the whole level sags two different effects do
you want one sometimes you want one and sometimes you want the other but this is a very very
powerful way of changing the effect of the compression on the mastering chain. So as I’ve said compressors don't make anything
louder they actually turn the signal down and the end result is that rather than something
getting bigger it tends to get thicker. So if you want to create a little bit of what
I think some people call glue using a compressor what you want to listen for is a lessening
of the differences, the clarity of individual elements in the mix, of everything sort of
comes together we lose a little bit of a transient energy so we can hear the sustained energy
a little bit better. So I’m going to play you before and after
of this Color In Me track and listen for the way everything gets a little closer together
you don't hear the reverb as well when everything's going on as you used to you don't even hear
the separation between the individual elements in the mix as well but everything feels a
little bit more together glued together. So it's a small difference that you're here
and here again in mastering land we're looking at maybe a dB, dB and a half of gain reduction
at the peak but has a real effect on changing the relationships in a mix between the individual
elements and so it can be used as a thickening agent but it needs to be used judiciously
if you start to feel like you're losing too much energy or you're losing clarity or you're
losing some of the sharpness or vividness of elements in the mix you might be compressing
too much or you can start playing around with settings. Use lower ratios, use longer attack times
shorter release times and you can change other parameters also to influence it, you can change
the shape of the knee. Hard knee will result in a harder sound, a
brighter sound and can also change even the detector type. So all of these will influence the amount
of smoothing that you get from a compressor. The knee of a compressor is something that's
a little bit tricky to understand. Usually when you take a look at a manual for
a compressor you'll see something that looks like a rounded or angular shape that describes
the signal level. And what happens to the signal as it approaches
the threshold, the short of it is that using a soft knee means that you're going to get
more compression starting at a lower level and a gradual onset of compression which results
in a smoother overall sound of the the classic compressor the LA2A, the fathers of compressor
types uses of soft knee so it’s favoured a lot for smoothing effects on vocals and
and signals that have a a longer-term envelope to them. A hard knee on the other hand will result
in a very fast onset of compression as a signal crosses the threshold which translates to
a brighter sound, usually it’s got a little more distortion and sometimes even hear the
effect of the compressor switching this is characteristic of the 1176 which is kind of
the other great ancestor of most modern compressors. Many modern compressors allow you to adjust
between a soft knee and a hard knee. My rule of thumb is if I want a smoothing
effect, a soft knee is better if I want a hard knee if I want to maintain the edginess
in an EDM track or in a Hard Rock track of any sort I'll usually go more for a hard knee
because I don't want to rob the track of the energy that's kind of baked into the mix. If you want to get really nerdy about compressors
we also think about the detector type. There are different ways of measuring level
Peak or average or something in-between and that will result in different behavior in
the compressor. If you use a peak detector it's going to be
using it's it's almost like Peak reading meter it looks at the peak level in a very short
window of time and uses that to to say: this is what the level is now or now or now compared
to the threshold so a compressor that uses a peak detector will track very fast-moving
level. Something that uses an average detector will
window the level over the course of the classic RMS measurement is 300 milliseconds are in
a third of a second the envelope of a sound that might take up a 1/3 of a second would
be something probably that's melodic like a vocal or a guitar or even a sustained bass
note so when you use an RMS detector the compressor is more likely to track the activity the level
of those elements and those instruments in a mix. So the question is do you want the compressor
to track your drums or do you want to track your sustained instruments. Again this works with knee and attack and
release all of these things come together and creating the overall compression effect,
and if you’re just getting started and just trying to search figure out compression I
would say don't worry about that other stuff stick with ratio, threshold and play around
a little bit with attack & release that's a really good starting point. In the case of the withdrawal of the Latrell
James track I probably would be inclined to use the peak detector because I want the compressor
to respond very quickly to the rhythm track and therefore preserve more of the punch and
a character and the sharpness the vividness of the rhythm track so just to remind you
what that sounds like. This is assuming that this track even needs
any compression. But in that case that's the compressor detector
type that I would use in the case of the color in me track I would probably use the RMS detector
type because in this case I'm looking for glue that brings together all of the sustained
elements in the track. So I think you can hear when I change it to
peak detector the compressor starts to respond to the drums and the sustained instruments
sound like they're jumping around like crazy the RMS detector really gives a smoother thicker
fuller sound across the entire mix. Probably the area of greatest challenge to
mix engineers is getting the relationship right in a low-end between the kick drum and
sustained bass it's understandable why that is our hearing isn't all that sensitive down
there and then most mix Engineers don't have speakers that will give him a good shot at
hearing energy below 80 Hertz at least not in a way that's even across the Spectrum and
so as a mastering engineer I'm often trying to adjust or reconcile or or make that relationship
better while I am generally not a fan of going into multi-band compression there are instances
where doing frequency specific compression is called for in really helpful and low bad
compression is one of them. A low band compressor is a very very powerful
way of controlling the low-frequency envelope in the relationship between the kick and the
bass this is sustain of the bass. If I find i’m needing to change that relationship
I will split a compressor so that I've got a low band and then everything else usually
around 150 Hertz or so and I will turn off the everything else band and only compress
the bass region hopefully you can hear that if you can't it's
probably time to get bigger speakers. So I'm just compressing that band and by changing
the attack time I can actually change the relationship between kick and bass with a
long attack time it'll let the kick come forward and compress the base and if I shorten the
attack time it keeps the kick in check and so if we raise the output, the makeup gain
of that band we’ll hear more of the base so let me try to demonstrate that for you
and will be listing across the entire mix. I'm going to play it turned off and then turned
on and I think you'll hear that with a fast attack the relationship between the kick drum
and the bass is changed and you hear more of the note of the bass. One more time, starting with it turned off. So if you find yourself constantly struggling
with this relationship this is way to help you modify that or adjust that after the fact. Thanks for watching are you listening if you
want to be notified about other episodes when they come out subscribe to the YouTube channel
and then you use the little bell icon feel free to go to the iZotope.com website there
are lots of educational materials there is there is the iZo sessions you can download
sound samples and experiment with them yourself you can download a copy of Ozone and I look
forward to seeing you next time, I hope you find this useful.
That first compression is really subtle. I had a hard time hearing the difference.
Welcome into my life, Ozone sidechain filter.
Edit: I want to elaborate a bit. This has been the missing piece I've been searching for for months. I remember seeing a video with Noisia (gold standard for EDM production in my mind) saying something along the lines of deciding how much "sub to send to the limiter" in his mix, and until I saw this, I was completely confounded by that statement.
Great way of telling stuff in a way that you understand it.
I love this video series. It really gives you an idea how thoughtful and precise you have to be with some tools. Not just slapping a compressor plugin on everything 'couse it's supposed to make it "beterrer"
Great video, but he should have turned off adaptive release for the demonstration.
this guys a legend
This video series is pretty informative, he says things others don't
RemindMe! 2 days
Great no-nonsense approach to mastering compression... which some might think is 180º away from mixing compression, but I feel like they are so, so related.