CLAVIA DMI AB CLAVIA NORD Rack 2X [89/114] Ad envelope

About Subtractive Synthesis Page 87

▼ If you release a key before the envelope has reach its sustain, it will immediately “jump” to the Release.

The effect of this can be studied in the illustration below.

▼ Often envelope levels can be made to vary with how hard you play the keys. This is used to make a

sound vary with your playing style, for example to make the sound brighter (filter envelope) or louder

(amplifier envelope).

AD-Envelope

A simpler form of envelope has Attack and Decay parameters only, and is therefore called an AD-enve-

lope. In effect, the AD-envelope behaves like an ADSR-envelope with Sustain set to 0 (see the picture at

the top of this page??). This type of envelope, often with amount and inversion controls, is suitable when

you want to affect the start of the sound only.

On the Nord Lead, the Modulation Envelope is of AD-type. Typically, it can be made to modulate the FM

amplitude or the pitch of Oscillator 2, to create a different timbre during the attack part of the sounds.

LFOs

An LFO is an oscillator, just like the ones that produce the sound in a synthesizer, but with two main dif-

ferences:

▼ The LFO produces very low frequencies, most often below the hearing range (up to 20Hz).

▼ The LFO is not used to produce sound, instead it is connected to other modules to provide modulation

of parameters.

If you for example route an LFO to pitch, you get a vibrato. If you route it to the filter’s cutoff frequency

you get a wah-wah type of effect. And if you route it to the amplifier of an instrument you get a tremolo.

The three basic parameters for an LFO are Waveform, Rate (frequency) and Amount:

▼ The waveform determines the type of vibrato, for example “regular” (triangle or sine), ramp (sawtooth)

or random.

▼ The Rate determines the speed of the vibrato.

▼ The Amount controls to what degree the LFO affects its destination.

Key Down

Key Up

Level

Time