- Hi, I'm Jordan from Kettner Creative.
In this video,
I wanna show you how a one knob audio compressor works.
A one knob audio compressor is increasingly common
in small analog audio consoles,
like the one in front of me today.
Now, in order to demonstrate how this compressor works,
we're gonna show you how it works
on a digital audio console.
And then we're gonna take what we learn over there
and bring it back to this one knob compressor.
And show you how it works by reducing all the factors
that are in play on a digital audio console to a single knob
on this analog audio console.
Before we do that, we need to talk a little bit
about what does an audio compressor do.
So an audio compressor narrows the dynamic range
of an audio input.
What does that mean?
Basically, it means that we need to make the quiet things
a little bit louder, we need to make the loud things
a little bit quieter.
We're squishing that dynamic range into a smaller window.
An example of this would be a kick drum.
We want the kick drum to sound the same all night.
So what we do is be compressed the heck out of it.
So as the drummer tires or the drummer gets excited,
the kick drum sounds the same and it sits in the same spot
in the mix the whole night.
On the opposite end, you have something like a vocal mic.
Vocalists will have a large dynamic range
that they wanna show off.
That makes it pretty hard to put into a mix sometimes.
So it can be helpful to compress that dynamic range
just a little bit.
You don't wanna overdo it and flatten them completely,
but you need to make it practical so it can sit
and do a range inside your mix.
So that's what we're trying to do.
Again, if we go to the opposite spectrum of that,
we have something like a podium mic.
Generally, a podium mic doesn't need a lot of dynamics
and you don't necessarily wanna be chasing it with volume
throughout the entire presentation.
So a compressor is helpful in narrowing that window
to make sure that if the podium presenter backs up
or gets really close to the podium mic,
that the volume of that audio input stays relatively
the same and your guests can hear at the same level
throughout the presentation.
So that's what we're going to show you today.
So next, we're gonna kick over to a digital audio console
so I can show you how a compressor works.
Okay, so here we are with our digital audio console.
What we have today is we have a Shure SM58
plugged into this audio console.
So you should be able to hear everything that I'm doing
and you'll hear what those changes sound like.
So what we have here with the digital audio console
is we have five different variables at our disposal.
We have the threshold, the ratio, the gain, the attack,
and the release.
Now, with the Yamaha one knob compressor,
the attack and the release are fixed at 25 milliseconds
and 300 milliseconds respectively.
So what that compressor is doing is that those
are staying fixed and these three variables are moving here.
So on the threshold,
the threshold on the Yamaha one knob compressor
moves between 18 decibels,
all the way down to negative seven.
So as you can see, if we dial this down,
we're gonna look up in the top right-hand corner
and we see that this threshold of the knee there,
that the bend is moving up and down.
So it comes all the way down to negative seven.
So what that means is any audio that comes and crosses
that threshold, you can see there,
then it gets squished by the compressor.
That's what that knee or that bend there is showing.
And what that bend is controlled by is the ratio.
So on an a Yamaha compressor,
we can go all the way from one to one when the compressor
is turned off and it goes all the way down to four to one.
So as you turn that compressor up,
anything that goes past this threshold
will get squashed four to one and anything in the middle.
So if you have that one knob compressor at halfway,
it'll be squashed at a rate of two to one.
But that squash only happens when the compressor kicks in.
You can see here, that red bar that comes down
as I speak louder, you can see it kick in there.
So that ratio of compression will only kick in
once the threshold is exceeded on the audio console.
So that's how it brings the dynamic range down.
Now, we also said that a compressor will increase
the things that are quiet.
And how it does that is it simply just adds gain
to the channel.
As we increases gain, so when the compressors is full
on a one knob compressor at seven decibels of gain,
that's what this second arrow is demonstrating here.
So that will make the quiet things a little bit louder.
You should've heard this microphone
just get seven dB louder as that added that gain.
So we can see here, when the compressor is off,
you won't be able to hear the difference.
I'm just showing you right now.
So when the compressors off, it'll have a threshold
of 18 decibels, means that it's wide open there.
There's a ratio of one to one and the gain is set to zero.
When that compressor goes full bore,
like we have with the microphone that's plugged in,
the threshold comes all the way down to minus seven.
The ratio goes four to one,
which means that's compressing four things for every one
that it leaves at regular volume and then the gain.
So the low, the quiet sections, are brought all the way up
by seven dB and the attack and the release
are at 25 and 300 milliseconds there.
Now, the attack and the release there are quite slow.
And that's just showing you that the Yamaha is trying
to have a slow buffer.
They don't wanna hear the compressor slamming.
They just wanna round everything out.
So that's how an audio compressor works.
And specifically, those are the variables
that are plugged in to the Yamaha one knob compression.
So now we're gonna undo this and then we're gonna go back
to the Yamaha console, we'll plug into there,
and you'll be able to hear how that sounds.
Okay, so we're back with the Yamaha MG10XU.
And now we're going to hear how this sounds.
So as we increase this one knob compression,
we're gonna expect to hear that threshold come down.
So it won't let things get louder without compressing them.
And then we're gonna hear that ratio.
So it's going to get more aggressive on the compression.
But on the flip side, we're going to hear seven decibels
of gain come in on the low-end to boost everything.
So we're gonna expect to hear it get louder
as we turn it up and in a much smaller,
more compressed dynamic range.
So let's go ahead and turn that up now.
"The quick brown fox jumped over the lazy dog".
Test, test, test.
"The quick brown fox jumped over the lazy dog".
You should really hear the compression kicking in now
as we go up to 10 'cause this does have a massive effect
on gain as well.
So we're all the way up at 10 now.
Now, we're going to come all the way back down to five.
The compressor is sitting right in the middle right now.
And now we're gonna roll it all the way off again.
We're going to hear how this sounds compared to where it was
when it was at half and when it was at full.
So I hope this video has been helpful.
I hope you have a better understanding
of how that one knob compressor works.
To me when I'm using the one knob compressor,
I generally don't take it up past half
just because it has that factor of adding so much gain.
But also, if you plan on using the compressor
with your audio channel here,
it's important to factor that in when you set your gain
on the channel.
Because if you add a compressor, that will also affect
your Aux outputs, your effects, and everything else
that that channel is interacting with because it adds gained
to the whole channel.
So that's important to keep in mind as well.
If you can't hear a difference,
if you don't see a big benefit of this,
then generally less is more.
Just don't use it if it's not effective in what
you're trying to achieve.
But again, for me as a general rule,
I never take these compressors up past half.
I'm generally somewhere around here,
which is the 11 o'clock to 10 o'clock position
on the compressor.
Hope this video has been helpful.
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And if you have any questions,
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Thank you so much for watching.
(energetic music) ♪ Audio fire ♪