Hey guys, Eric Tarr here for theproaudiofiles.com.
In this video I’m gonna be doing a side by side comparison of two different kinds
of modulation effects.
Specifically the flanging effect and the phaser effect.
I get a lot of questions about these modulation effects with one question being what is the
difference between flanging and phasing.
Another question being, what are these processors actually doing to my input signal.
So I came up with this little demonstration that I’ll show you to hopefully illustrate
and answer these questions.
Let’s get to it.
I’ve got a Pro Tools session already set up where I’m gonna be synthesizing a signal
that I’m gonna send through each of these plugins separately and then analyze what that
plugin is doing.
So I’ve got my signal generator plugin pulled up and I’m creating some white noise.
I specifically chose white noise because it has energy all the way across the spectrum
from low frequencies up to high frequencies.
I’ve printed this white noise onto a separate audio track, that way every time through,
I’m gonna be passing the same exact signal through each one of these plugins.
I’m gonna be using the very basic effects, the stock plugins that come with Pro Tools:
Air Flanger and Air Phaser.
But you can do this demonstration with all kinds of different modulation effects.
Then after the signal goes through the plugins it’s gonna come over here and be analyzed
inside of iZotope’s Ozone 5 meter bridge.
What you’ll see here is the spectrum and then also the spectrogram to see how these
frequencies are changed across time.
So before I even bring in the plugins I can play you back the white noise and you can
see what it looks like.
[white noise + iZotope Ozone 5 Meter Bridge]
Next up what I’m gonna do is focus on the flanger.
And what I’ll do is bring it in, and you can see what happens all the way across the
spectrum when I’m using the flanging effect.
So I’ll go ahead and bring it in.
Right now I’ve got it set up on the factory default.
But for the sake of the demonstration I’m actually gonna change a few things so I can
make it a very basic flanger.
So I’ll slow down the depth, slow down the rate.
This will help you be able to see what’s taking place.
And bring down the pre-delay.
So I’ll bypass it to begin with and then bring it in.
[Air Flanger + iZotope Ozone 5 Meter Bridge Spectrogram]
So what you can see happening is across the spectrum there are these notches that are
carved out.
And this is called comb filtering.
And you can see this in the spectrum and also the spectrogram how these notches are sweeping,
they’re changing across time and they depend on things like the depth and the rate and
the pre delay.
So if I change some of these parameters you can see what the effect is.
[flanging effect]
So by changing the pre-delay, what I’ve done is increased the number of notches and
they show up at different places throughout the spectrum.
I’ll lower it back down again.
Now I can change the rate.
What that’s gonna do is the sweeping of the position of those notches is going to
happen at a quicker rate.
Next up is the depth.
Bring this back down.
So the depth parameter is gonna control how far across the whole frequency spectrum these
notches are going to sweep.
Alright, so that basically covers the flanger.
I guess another thing to point out is that an important thing is that these notches are
occurring at harmonics of each other.
At even harmonics and odd harmonics of where these notches — the lowest one is occurring
— you have all these other notches taking place.
And that’s just a product of the signal processing.
Next up, let me move on to the phaser effect.
Just like before I’ve got the factory default but I’ll change a few things so that it’s
a very simple phasing effect.
I’ll slow down the rate, slow down the depth and we’ll see what’s happening here.
Start in bypass and then bring it in.
[phasing modulation effect]
So right now we have a single notch that’s being taken out rather than having a bunch
of notches in the entire comb filter.
Ok, the center of that notch where it’s occurring is around 1000 Hz, but it’s gonna
sweep a little bit based on the rate and the depth.
So if I increase the depth you’ll see that the sweeping goes further and further across
the spectrum.
[sweeping phaser]
I can change the rate and it’ll go faster.
Another thing that I can do is change the number of poles.
This will actually change the number of notches that are occurring across the spectrum, so
I can go from having two poles, where you have essentially one notch to four poles.
Now I have two notches.
Six.
Three.
And then with eight you get four.
An important thing to point out is where the frequencies — these notches occur — they
don’t necessarily have to be harmonically related.
Alright, the last thing I’ll point out is with feedback you can actually increase the
resonance of where these notches are occurring too.
Alright, so that basically covers the effect that the flanger and the phaser have on the
input signal.
They also show you side by side what’s taking place.
With the flanger you have this sweeping comb effect that starts up at high frequencies
and goes down and back up.
With the phaser, you can center it around a specific frequency here and just sweep around
there.
You also with the phaser you can just notch out one decrease in amplitude across the spectrum
rather than having a bunch of them show up like what happens with the flanger effect.
In my next video I’m actually gonna show you behind the scenes what’s taking place
with the signal processing that causes these comb filters and notches to occur in these
different kinds of effects.
So stay tuned for that guys.