Korg musical instruments

Playing and editing Programs

EGs (Envelope Generators)

An envelope creates a modulation signal by moving

from one level to another over a speciﬁed time, and

then moving to another level over another period of

time, and so on.

The HD-1 includes three EGs, for Pitch, Filter, and

Amp. These produce time-varying changes in pitch,

tone, and volume respectively. They can also be used

to modulate a number of other Program parameters

via AMS.

Using Alternate Modulation (AMS) and the AMS Mixers

AMS (Alternate Modulation Source) refers to any of

the assignable modulation sources in OASYS,

including:

• Built-in physical controllers, such as the Joystick,

Ribbon, and Real-Time Knobs

• Incoming MIDI controllers, or MIDI controllers

generated by KARMA or the Vector EG

• Modulators such as the Filter, Pitch, and Amp EGs,

the LFOs, or the AMS Mixers

Intensity is a parameter that sets the degree (speed,

depth, amount etc.) to which AMS will control the

modulation.

A number of frequently-used modulation routings,

such as using the joystick to vary the pitch, are

provided as additional, dedicated routings, separate

from AMS.

Note that not all AMS sources may be available for

some modulation destinations.

For details on alternate modulation and AMS, see

“Alternate Modulation Sources (AMS),” on page 965 of

the Parameter Guide.

Using the AMS Mixers

The AMS Mixers combine two AMS sources into one,

or process an AMS source to make it into something

new.

For instance, they can add two AMS sources together,

or use one AMS source to scale the amount of another.

You can also use them to change the shapes of LFOs

and EGs in various ways, modify the response of

realtime controllers, and more.

The AMS Mixer outputs appear in the list of AMS

sources, just like the LFOs and EGs.

This also means that the original, unmodiﬁed inputs to

the AMS Mixers are still available as well. For instance,

if you use LFO 1 as an input to a AMS Mixer, you can

use the processed version of the LFO to control one

AMS destination, and the original version to control

another.

Finally, you can cascade the two AMS Mixers together,

by using AMS Mixer 1 as an input to AMS Mixer 2.

Adding two AMS sources together

AMS mixers will do different things depending on

their Type setting. The A+B setting merges two AMS

sources into one. This can be handy when you need to

add one more modulation source to a parameter, but

you’ve already used up all of the available AMS slots.

For instance, let’s say that you’re using an LFO to

modulate Filter Resonance, and then you decide that it

would be interesting to scale that parameter with an

EG as well. Resonance has only a single AMS input,

but you can easily merge the LFO and the EG together

using the A+B AMS Mixer:

1. Assign the LFO to AMS A.

2. Assign the EG to AMS B.

3. Assign the AMS Mixer as the Filter Resonance

AMS source.

AMS Mixer A+B example

Scaling one AMS source with another

When the Type is set to Amt A x B, the mixer uses the

AMS B input to scale the amount of AMS A. For

instance, you can control the amount LFO1 with the

Filter EG, or control the amount of the Pitch EG with

the ribbon.

Level

Time

Attack Time

Decay Time Slope Time Release Time

Attack Level

Start Level

Sustain Level

Break Level

note-on note-off

Release Level

AMS A: LFO

AMS B: EG

A+B Output