Hi, and welcome back.
My recent video about parallel EQ and NOVA got lots of insightful comments as usual,
not least this one from Fabien, one of NOVA's developers, which I've pinned at the top of
the comments section, and which I'll come back to shortly.
So, one comment raised the issue of multiple instances in series.
Actually the initial comment got it the wrong way around, but was immediately corrected,
so the hive mind of my viewership got there between them.
Anyway, here's the response we get running two adjacent boosts in Pro-Q3… and here's
what happens if we run two instances of Pro-Q3 in series, with each instance running one boost.
No difference.
The filters run in series either way; same result.
Now here's NOVA running two adjacent boosts… and now two NOVAs in series…
not at all the same result.
Now the second band is being fed the output of the first band, instead of the original
signal, and we've effectively turned NOVA into a serial EQ design.
So by implication, the extra two bands available in the Gentlemen's Edition are more valuable
than they may first appear, as you can't replicate them by just loading another instance of the
free NOVA instead.
Next, a question.
It's the one from my video title: "what type of EQ should I be using, and when?"
Before I answer that I want to clarify something: at the end of that video I posed the rhetorical
question, “what was the point of this video?”.
And the more serious answer to that question is: learning how your tools work, and finding
their intrinsic strengths and weaknesses, will help you to not worry about those technical
differences when mixing.
One thing I've become conscious of is that, while I enjoy analysing my tools and discovering
all the tiny little differences, my videos on the subject might give the impression that
this is how I approach mixing.
And that would be entirely the wrong impression.
In fact, when I geek out with plugin doctor or null tests, this is more comparible with
a musician popping on a metronome to practise their scales and arpeggios.
They do so to get those movements ingrained into muscle memory, so that when they perform
they don't have to think about the technical details.
Likewise, when I analyse my plugins strengths and weaknesses, its so that I don't have to
worry about it when mixing, and so that, as far as possible, when I want something that
behaves a certain way, I know what to reach for.
In the heat of a mix, you shouldn't be worrying about which EQ to use.
You should be thinking about which frequencies to cut or boost, and by how much.
And, if you make good decisions about those, you're probably fine with your stock EQ.
Honestly, your stock EQ is almost certainly an order of magnitude better quality than
the crappy cheap analogue console EQs I learnt on.
I'm serious.
You guys don't know you're born!
The biggest reason to reach for something else might be high frequency cramping.
I've made a video specifically explaining what that is, so I'll just pop up a card here
and won't repeat myself.
If your stock EQ cramps (and not all do) then you might want to choose something else for
your airy high frequency boosts.
But that doesn't have to mean spending money: the free NOVA does great sounding high frequency
boosts, as does the free Slick EQ, also from Tokyo Dawn Labs.
Another possible reason you might want something different to stock is saturation.
Most stock EQs are clean and free of non linearities, as is Pro-Q3 and NOVA, if you ignore the dynamics
and saturation options.
But it is possible for a mix to be too clean, in which case more colourful EQs might help
If you're boosting the low end of a part, but it gets boomy or muddy before it gains
the weight or thickness you wanted… or if you're boosting the high end, and it gets
harsh and abrasive before it gains the brightness and airiness you wanted… both are signs
that you might need to add some extra harmonics as well as boost those that are already present.
Slick EQ can do very tastefully subtle saturation for EQ boosts… and I've become very fond
of the colourful shelves and bells available in Volcano 3…
I'm also a fan of Spectre from Wavesfactory, not strictly an EQ plugin but nevertheless
great for colorful EQ style boosts.
But bear in mind that there are many ways to skin a cat, and colourful EQ is not the
only way to add desirable harmonics.
I've recently become a fan of this IK Tascam tape simulator, for those times when I want
thicker, richer bass… and I've long been a fan of U-He Satin for the airy sheen it
can impart to the high frequencies.
If you choose to stick with clean linear EQs and add the harmonics elsewhere, that's perfectly
valid and you're not doing it wrong.
Alright, what about linear phase?
I'll be honest, I hardly ever use it myself.
And perhaps this is self reinforcing: the fact that I rarely prefer it might mean that
I fail to try it out in situations when it might be helpful.
But, here's the thing: real life is minimum phase.
When sound bounces around in the air as acoustic energy, the phase shifts as the frequency
response changes, and really, they're both different sides of the same coin.
Here's the impulse response of a minimum phase filter: the ringing comes after the impulse:
effect follows cause: this is natural and wholesome, like motherhood and apple pie.
Now here's the impulse response of a linear phase filter: the ringing starts before the
impulse: effect precedes cause: this implies time travel, and is the work of the devil.
And on a technical level: the kernel of a minimum phase IIR filter is probably just
a handful of multiplications and additions.
But a linear phase FIR filter has to dice your signal into separate chunks, fast Fourier
transform them into essentially an image file, inverse fft them back, then reassemble all
the chunks using some kind of windowing function.
I may have got some or all those details wrong, but you get the gist: linear phase filtering
means much more complex and profound processing, which is reflected in the CPU use.
The idea that linear phase is somehow purer and more natural than minimum phase, because
it avoids the unnatural phase shifts, is literally exactly backwards.
That said, there are a couple of scenarios where I do use linear phase.
Mid side processing is one: if I want to narrow the stereo width for low frequencies, without
changing the stereo image at all for mid and high frequencies, I'll use linear phase filtering.
I've covered that in more detail in another video, card at the top hopefully.
And, the only situation where I always use linear phase is if I'm rolling my own crossover
filters.
Not that that's something I have to do very often, but nevertheless.
Funnily enough I got a question specifically about that subject, so let's run through the
issue.
Here's Metaplugin running inside Plugin Doctor, with two instances of Pro-Q3 running in parallel.
I've set up one as a low pass filter, and the other as a high pass filter, both tuned
to the same frequency.
And as you can see, the combined frequency response is not ideal.
We've got a massive notch at the crossover frequency.
That won't do at all.
Before we worry about that however, these filters are both set to the default 12dB per
octave setting.
We want to be steeper than that: let's set them both to 24dB.
And actually that's improved matters already: the notch has gone, but we now have a bump
instead.
Now, the usual way to define the cutoff of a filter is the 3dB down point.
So, at the cutoff frequency, both halves of the signal are being attenuated by 3dB.
But adding the same signal to itself usually doubles the amplitude, which means a boost
of 6dB.
Ok, 6.01 dB if you're being pedantic.
Or is it 6.02dB as one commenter claims?
Honestly I haven't checked that, but I'm one of those normal people that's happy to round
it to 6dB regardless.
So that suggests that we need each filter to be attenuating 6dB at the crossover frequency,
rather than 3dB.
Now, we could possibly adjust the lowpass cutoff down a bit, and the highpass up a bit
to compensate.
But I don't want to open that can of worms: I want to be able to just set the same crossover
frequency in both and have it work.
And fortunately there's an easy way to achieve this.
First I'll select the lowpass filter, and switch it to 12dB per octave instead of 24.
Don't worry, we will end up back at 24, bear with me.
Now, split it into separate filters for the left and right channel.
Then make sure both filters are selected… and switch them back to stereo.
This is just a quick and easy way to stack up two 12dB filters at the same frequency,
which gives us 24 dB per octave again, but now the cutoff frequency is being attenuated
by 6dB instead.
We have, in effect, just shifted the cutoff slightly lower.
Let's do the same for the high pass filter… and that's a lovely flat frequency response
when they're recombined.
But notice we're still in zero latency mode.
So what's the problem?
Well, first of all, what if I want a different crossover steepness?
Let's switch all the filters to 6dB per octave, to make an effective 12dB per octave crossover…
and there's that pesky notch again.
Ok, so actually that's not the end of the world: if I flip the polarity for one of the
bands… we flatten out the frequency response again.
And this still works if I switch to 18dB filters, to create an effective 36dB per octave crossover:
still good.
But if I try to make a 48dB crossover… the notch comes back, and I have to flip the polarity
back again to fix it.
And of course, the other issue with a minimum phase crossover is, the phase shift.
You can flatten out the frequency response, but you still get a hefty phase shift at the
crossover frequency, as if you ran your signal through an all-pass filter.
Now many people will tell you that static phase shifts are inaudible.
I prefer to think of it differently: most of the time your brain decides that static
phase shifts are not important and ignores them.
But, sometimes it doesn't.
And, if you can swerve the issue entirely, why the hell not?
So let's switch both instances to linear phase mode… and tell Metaplugin to recalculate
the latency.
Now, of course, the phase shift is gone.
But also, and more importantly, the frequency response is still flat… and remains flat
whatever filter slopes I choose, so long as I match both bands…
with no need to flip the polarity with any settings… which makes this setup much easier
to not screw up.
And of course, this becomes much more of a consideration if you're trying to setup more
complex crossovers with more bands.
So, those are the only two ways I personally use linear phase EQ.
But I can't ignore the fact that many people like it for high frequency boosts, especially
in a mastering context.
Here's one possible explanation.
The main issue with linear phase filtering, ignoring practical issues like latency or
CPU load, is pre-ringing.
That's what we saw on the impulse earlier: the filter starts to ring ahead of the impulse,
and sometimes this can smear the transients, and reduce their impact.
This is mostly only an audible issue with low frequencies.
But the pre-ringing happens at mid and high frequencies as well, its just too short to
discern.
Perhaps the resulting very subtle softening of transients is actually what some people
like about linear phase high frequency boosts?
Other reasons to load a specific EQ might be the control set: sometimes I like to use
Pultec style EQs.
If you've got a kick drum that sounds a bit like a cardboard box… and you want it to
thump like a kick drum instead…
the classic Pultec trick gets you there straight away, no problem.
Now, I could probably recreate this same frequency response with Pro-Q3, and get essentially
the same sound… in fact, let's try it: here's what we get if I EQ match the Pultec kick
with the Fabfilter EQ… what do you think?
Do they sound the same?
The biggest difference, in my opinion, is the user experience.
The FabFilter EQ tends to pose the question: are you sure this crazy frequency response
is the one you're after?
While the Pultec style plugin pats you on the back and congratulates you on your good
taste, and would never dream of judging your life choices.
Ultimately, once it's in the mix, it doesn't really matter how you create that frequency
response, the listener won't know the difference.
So if you know in advance that you want that Pultec style sound, why burden yourself with
all the extra options, when you can just twist 3 knobs and move on?
And that doesn't mean that, further into the mix process, you can't throw on a Pro-Q3 or
similar as well, and tweak things further.
Of course you can, and I'll often do exactly that.
Another reason to load a specific EQ might be a specific feature that's not present in
your stock or goto EQ.
EQ match is a good example: I wouldn't normally bother using it to replace my Pultec style
plugins of course!
But if you need to comp together takes recorded on different days on different microphones,
it can be a lifesaver.
Or maybe you've got a stereo file with an unbalanced image that could be improved by
EQ matching one channel to the other?
It's not something I use every day, but can be useful occasionally.
Here's another example, courtesy of Slick EQ Gentleman's Edition.
I sometimes load this up for broad tone shaping options, as it's easy and fast to operate
even with the graph display hidden away so it doesn't worry you.
But there's a feature unique to the GE version that I often load it up for: the phase rotation
for the low band, which sometimes helps low frequencies to sit better in the mix.
It also, sometimes, makes the low end turn to mush.
And sometimes it's hard to hear any difference at all.
Honestly I'm no good at predicting when this trick will work, and all I can say is try
it and see if it feels better.
But sometimes I'll load Slick EQ GE to deal with the low end of a part specifically because
I want to be able to toggle that feature on and off to see if it helps.
So what about parallel EQ vs serial: the can of worms I opened in my last video?
It was suggested in the comments that, as adjacent cuts or boosts remain more separate
in a parallel design, that it will therefore be better for surgical adjustments.
I'm a little sceptical of this to be honest.
Q3 is quite capable of tightening up the Q for these bands, so they cease to affect one
another: are you saying this isn't surgical enough?
And, if you specifically want that twin peaks response that the parallel EQ provided, you
can get pretty close by adding a third band to dip the middle.
Likewise, if you want that more unified, flat topped single band response from NOVA, you
can get pretty close by adding a third band to boost the middle instead.
Basically what I'm saying is, either topology is capable of creating any frequency response
you're likely to need, with the only difference being, perhaps, how many bands you'll need
to achieve it.
And these brings me to a point that Fabien made in his comment, which I should perhaps
have emphasized more in my video: NOVA was designed from the ground up as a dynamic EQ,
while Pro-Q3 is very much a conventional EQ that's grown some extra dynamics features.
That may seem like an irrelevant detail, but in fact that's the real reason for the parallel
design in NOVA: artifacts from the dynamics processing add up in parallel instead of multiplying
in series, and potentially give you a much cleaner overall result.
When I load NOVA its never because of the static EQ behaviour, and always because I
want some of its dynamic goodness.
And this, combined with another of Fabien's insights, helps to clear up a little mystery.
You may have detected my slight confusion in the last video, that the differences between
the different curve options seemed so slight in my null tests.
That didn't chime with the impression I had that the differences are significant and easy
to hear.
Well, it turns out that in fact the dynamic behaviour of these curve types is very different.
And of course, I normally use NOVA precisely for its dynamic behaviour.
So I was in fact hearing differences that simply don't show up when measuring the static
EQ curves.
It's always nice when a deeper understanding confirms what your ears were telling you,
rather than, as is so often the case, precisely the opposite!
Anyway, its taken me longer than I expected to reach this answer, but here it is: if you
have to ask which EQ you should be using, you should be using the stock EQ, or your
usual goto EQ, and just worrying about which frequencies to tweak.
If you ever load something else in the heat of a mix, it should be because you know it
offers something specific which you think might help in that situation.
Otherwise, focus on the frequencies, because that's what usually matters.
That's all, thanks for watching.