The Band Pass Filter 
is like a Low Pass Filter
PLUS a High Pass Filter.
So it passes only the middle frequencies
(near the cutoff point)
When set low, it's like a Low Pass Filter.
Set high it's like a High Pass Filter.
That's it for the BPF.
Next we have the Peak Filter.
Next is Bypass,
Last is Bypass,
which effectively bypasses the filter entirely.
So, that's it for the GAIA's 5 filter types .
OK I've set it back to Low Pass Filter
There's another very important feature:
Resonance.
Resonance is...
Ok let's start with Resonance at zero.
What happens when we
change the Cutoff?
It sounds like this.
Now, with Resonance just above halfway...
Hear that? It's like 'meeyonnnnn'.
Let's set it even higher.
What Resonance does is
emphasize the frequencies
near the Cutoff point.
Depending on how high Resonance is set,
you can extremely emphasize those
frequencies, which produces
the characteristic Filter Sweep sound,
that 'meeyooonnnn' sound...
This sound here has
'synthesizer' written all over it.
Last is the Amplifier,
which sets the overall volume
of the sound.
The volume is changing yeah?
It's really a simple system...
but we haven't looked at the sliders
down here at the bottom yet.
The sliders are critically important!
Technically speaking, the sliders
allow us to edit what we call
Envelope Generators.
Envelope Generators shape the sound
and change it over time.
For example, let's use the Amp
section this time, shall we?
If you look, there's a diagram here,
Can you see it?
It starts with 'Key on',
then goes to the 'A' (Attack) time,
rises to a peak,
then to the 'D' (Decay) time,
which falls (decays)
to the 'S' (Sustain level),
and after you release the key,
which is labeled as 'Key off', 
the 'R' (Release time) finishes the envelope.
This is the ADSR.
This is another key concept!
A = Attack
D = Decay
S = Sustain
R = Release
(explains in Japanese)
Ok? Let's put Sustain all the way up.
Back to where we started..
What happens if we raise the Attack time?
The sound fades in slowly.
Right? 
Ok, let's move it back down to zero again.
At zero, it sounds as soon as you press a key.
What about release?
This affects what happens after you release a key.
Get it?
It fades out slowly now.
OK back to zero.
Right now, the Sustain is
set to maximum, with
everything else set to zero.
So the sounds starts as soon as
you press a key and rises instantly
to the max Sustain level,
and stays there, until you release the key,
and the sound is abruptly cut off.
Chop!
Like that.
Let's turn the Sustain off
by setting it at zero,
and see what happens.
It's kind of a quick blip sound now.
What's happening is the envelope is
immediately going to the top level,
but since the levels are set to zero,
it only sounds right when you press a key.
Let's raise the Decay and see what happens.
Gradually raising it does this...
So even though I'm holding the key down,
the sound slowly fades out.
This is just like a piano.
After the hammer strikes the string,
the string vibrates, making a sound,
but as the string stops vibrating,
it fades out.
This is exactly like that.
So, we can shape how a sound changes over time
using Attack, Decay, Sustain, Release,
more simply, the ADSR,
also known as the Envelope Generator.
There are Envelope Generators
on the Amplifier,
and the Filter too.
The Amplifier envelope controls volume,
but the Filter envelope controls the brightness.
You hear how the brightness changes?
going up + down
like what we did with volume...
That's how you can use the Filter envelope.
There's also an Envelope Generator
here in the Oscillator section,
but this one only has Attack + Decay.
This one lets you change
the pitch of the Oscillator over time.
Let's try it out.
We have to adjust the Envelope Depth first.
Let's set it halfway up.
Let's raise the Attack
It's going up...
then immediately drops. Let's raise the Decay.
It's like a mountain, the pitch goes up
then down.
Ok, now, the Envelope Depth is
set to a positive value, but
let's set it to a negative value
and see what happens.
Now the mountain's upside down.
Mmmm that's fun!
So by doing this kind of editing,
with Envelope Generators,
a variety of time-based changes
are possible:
timbre, volume, pitch, etc.
any way that you want.
And that is a lot of fun!
AND we haven't even touched on 
the Blue section yet—the LFO,
which stands for
Low Frequency Oscillator.
an ultra-slow Oscillator used to
impart a waver, like tremolo,
onto the sound.
Here, written in red, no wait, yellow,
we have Pitch, Filter, Amp.
What do you suppose that's for?
Well, over here we have the Rate knob,
which controls the speed of the LFO,
turn it up and the light blinks faster.
Ok, so let's raise the Pitch slider
and see what happens.
Ok, the pitch is fluctuating.
How about moving the Amp slider?
Ok, what about Filter?
let's move the slider down this time.
This is what you can do with the LFO!
You can also change the LFO shape.
Here's the Wave section,
like we had for the Oscillator,
but these waveforms are just for 
the LFO, just for modulation.
For example, let's set it to Square
and see what happens.
You get this kind of sound.
Amp and Filter...
There's also a Fade Time slider here,
which lets you change how fast
or slow the LFO affects the sound
after you press a key.
When it's set to zero,
it's on as soon as you press a key.
If you raise it, though
at first there's no LFO effect,
it fades in slowly.
The interval between Key on
and LFO on is Fade Time.
So, to wrap up, we've looked into the
Oscillator, Filter, Amplifier,
and of course LFO
are the building blocks
from which a huge variety
of sounds can be made.
This is the fundamental system of
sound creation on the GAIA,
it's 'secret', so to say.
Once you understand this,
you'll be able to make sounds
not only using the GAIA, but also
with basically every synthesizer ever made.
Because they basically all work 
in the same exact way!
If you can grasp these concepts,
your understanding of synthesizers
will just get deeper and deeper.
Oscillator, Filter, Amplifier, LFO.
Envelope Generators too.
Don't ever forget these concepts!
