Lfos; Summary; Ultranova Signal Low Diagram - Novation ULTRANOVA Mode D'emploi

In the UltraNova, Envelope Generators 3 to 6 can be used for special purposes, such as
Modulating the Wavetable index or FX levels.
KEY "ON"
FILTER
CUT-OFF
ATTACK DECAY
TIME

LFOs

Like the Envelope Generators, the LFO section of a synthesizer is a Modulator. Thus in-
stead of being a part of the sound synthesis itself, it is used to change (or modulate) other
sections of the synthesizer. For example, an LFO can be used to alter Oscillator pitch, or
Filter cutoff frequency.
Most musical instruments produce sounds that vary over time both in volume and in pitch
and timbre. Sometimes these variations can be quite subtle, but still contribute greatly
towards characterising the inal sound.
Whereas an Envelope is used to control a one-off modulation over during the lifetime of a
single note, LFOs modulate by using a repeating cyclic waveform or pattern. As discussed
earlier, Oscillators produce a constant waveform which can take the shape of a repeating
sine wave, triangle wave etc. LFOs produce waveforms in a similar way, but normally at a
frequency which is too low to produce a sound that the human ear could perceive. (In fact,
LFO stands for Low Frequency Oscillator.)
As with an Envelope, the waveforms generated by the LFOs may be fed to other parts of
the synthesizer to create the desired changes over time – or 'movements' - to the sound.
The UltraNova has three independent LFOs, which may be used to modulate different
synthesizer sections and can run at different speeds.
ultranova SIgnal floW DIagram
OSCILLATOR 1
OSCILLATOR 2
OSCILLATOR 3
NOISE
RING MOD 1*3
RING MOD 2*3
12
KEY "OFF"
SUSTAIN
RELEASE
MIXER
A typical waveshape for an LFO would be a Triangle wave.
PITCH
TIME
Imagine this very low frequency wave being applied to an Oscillator's pitch. The result is
that the pitch of the Oscillator slowly rises and falls above and below its original pitch. This
would simulate, for example, a violinist moving a inger up and down the string of the instru-
ment whilst it is being bowed. This subtle up and down movement of pitch is referred to as
the 'Vibrato' effect.
Alternatively, if the same LFO signal were to modulate the Filter cut-off frequency instead of
the Oscillator pitch, a familiar wobbling effect known as 'wah- wah' would be result.
As well as setting up various sections of the synthesizer to be modulated by LFOs, ad-
ditional Envelopes may also be used as modulators at the same time. Clearly, the more
Oscillators, Filters, Envelopes and LFOs there are in a synthesizer, the more powerful it is.

Summary

A synthesizer can be broken down into ive main sound generating or sound modifying
(modulating) blocks.
1 Oscillators that generate waveforms at a various pitches.
2 A Mixer that mixes the outputs from the Oscillators together.
3 Filters that remove certain harmonics, changing the character or timbre of the sound.
4 An Ampliier controlled by an Envelope generator, which alters the volume of a sound
over time when a note is played.
5 LFOs and Envelopes that can be used to modulate any of the above.
Much of the enjoyment to be had with a Synthesizer is with experimenting with the factory
preset sounds and creating new ones. There is no substitute for 'hands on' experience.
Experiments with adjusting the UltraNova's many parameters will eventually lead to a fuller
understanding of how the various controls alter and help shape new sounds.
Armed with the knowledge in this chapter, and an understanding of what is actually hap-
pening in the machine when tweaks to the knobs and switches are made, the process of
creating new and exciting sounds will become easy - Have fun.
ENVELOPES 3 - 6
ENVELOPE 1
ENVELOPE 2
FILTER 1 DISTORTION FILTER 1
FILTER 2 DISTORTION FILTER 2
LFO 1 - 3
FX 1
FX 2
AMP FX 3
FX 4
FX 5
OUT