Hey guys, Eric Tarr here for theproaudiofiles.com. This is my second in a two-part series on
the differences between phasing and flanging modulation effects. In my first video I looked
at side by side what each one of these processors is doing to an input signal. In this video
I’m gonna demonstrate how these effects are actually created — what’s going behind
the scenes of the plugins to create these effects. Just like before I’m gonna be working
inside of Pro Tools. i’ve synthesized a signal that I’m gonna be using as a test
signal to analyze.
So I’ve started out with the white noise inside of the signal generator plugin and
I’ve printed it onto a separate audio track. That way each time I go through and analyze
the signal I’m working with the same exact signal. Then I’m gonna be feeding it into
the iZotope Ozone 5 meter bridge plugin. I’ve got the spectrum and the spectrogram displayed.
So the white noise by itself looks like this
[white noise via signal generator plugin]
So it’s got energy all the way across the spectrum from low frequencies to high frequencies.
Next, let me talk about how the flanging effect is actually created. What I’m gonna do is
bring up some other tracks that I’ve already got going. Alright, here I’ve got my original
white noise that’s printed onto this track here but then what I did is I duplicated it
and I’ve got several different versions of the same track. So if I zoom in here, all
the way in where I can see it at the sample level, what you’ll notice is I’ve got
the same exact signal on all these tracks. The only difference is I’ve just shifted
the original signal by one sample for each one of these tracks. So to go from this one
down to my next one here I’ve called 1 sample, I’ve shifted it over, I’ve nudged it over
by one sample. Then for the next one I’ve got compared to the original I’ve got it
nudged over by two samples. My third one, over three samples. All the way down to eight
samples. The reason why I did this is to actually show you that the way that a flanging effect
creates this comb filter that sweeps across the spectrum is it actually uses very short
delay times such that when it adds a signal with itself that’s been shifted by one sample
or by 2 samples or by 3 samples of delay, what ends up happening is there are certain
frequency that get cancelled. And that’s exactly how the comb filter gets created.
Now let me show you how this works. Right now I’ve got the original flanging noise
that I’m gonna use here going through the Ozone plugin. It looks like this.
[white noise]
Now watch what happens if I bring in a signal, the same exact signal that’s been duplicated,
but I delay it by one sample so there’s a one sample delay between these, watch what
happens. It’s kind of subtle to see but you end up having the high frequencies rolled
off up here.
[white noise]
So right now we have a kind of spectral effect taking place by actually using a time delay.
Now if I mute the 1 for 1 sample and I bring in the 1 for 2 samples you’ll see that there’s
another notch that shows up. So now I’ve done a time delay, a very short time delay
of that white noise signal and added it in with itself. And look what happens.
Next up if I do a time sample of three samples of delay it looks like this. So the notch
is occurring at a different place than 2. And 4, 5, 6, 7 and 8 you can see what happens.
So what on a conceptual level how the flanger creates this kind of sweeping comb filter
is actually to use very short delay times where it’s blending in together the original
signal with one that’s been delayed by just 1, 2, 3 or a few samples and it modulates
that. So rather than just sticking with a delay time of 1, 2 or 3, it actually moves
between these different samples of delay and what that’s gonna do is shift where these
notches occur across the spectrum. So that’s how the flanging effect is created.
Next let me move on and show you how the phasing effect is created. So I’m gonna get rid of these
tracks and bring up some more that I’ve already prepared. Okay. Here what I’ve done
is I’ve got that same white noise signal printed, got that here in the purple track.
And then what I did is I duplicated it down here on a separate track. So now I’m gonna
be mixing together the original signal with a version of itself. The only difference is
I’m gonna be using a phase plugin, and this is one that’s created by Waves, it’s called
InPhase. What it allows you to do is actually to shift the phase of a signal at specific
frequencies. So for low frequencies and high frequencies I’m leaving the signal as it
was before. Zero degree phase shift. However at this frequency here — at 1000 Hz — I’m
actually gonna be shifting the phase by 180 degrees. I’m gonna be taking it out of phase
so now that the frequencies here are out of phase and have destructive interference with
the original. So if I show you the original, right, I’ve brought it up so I have the
same number of samples of delay of internal processing, but I’ve got it turned off now
here, then my second version of it, right, I’ve got the part here at 1000 kHz where
I’m doing the phase shift. Watch what ends up happening when I’ve got the original
and then bring in the second one here.
[white noise + Waves InPhase plugin]
So what the phaser effect is gonna do is flip the phase of certain frequencies and then
modulate the frequency here so I can sweep this one around and you can see how this sweeps
across the spectrum then.
[noise + Waves InPhase]
And
this is exactly what’s taking place behind the scenes inside of the phaser plugin. Now
it’s gonna be doing it in a much smoother way rather than stepping from one frequency
to another, but the idea is you’re gonna be flipping the phase on certain frequencies
and then adding them together so you have constructive interference with the two signals
when they’re at zero degrees phase shift. And destructive interference where they cancel
out just at these frequencies. And that’s how the phaser effect is created.
Hopefully these last two videos you guys have given you a good idea about the differences
and similarities between phasing and flanging. It shows you what is actually happens, what
the plugins are doing to your input signal and then also how these effects are actually
created by using signal processing. That’s all there is to it. Play around with this
yourself, guys. Try it out with different kinds of signals, not just noise and see for
yourself what’s taking place. Take care guys.