Novation UltraNova Benutzerhandbuch Seite 11

Noise Waves
Volume
These are basically random signals, and have no one fundamental frequency (and therefore
no pitch property). All frequencies are at the same volume. Because they possess no pitch,
noise signals are often useful for creating sound effects and percussion type sounds.
Digital Waveforms
In addition to the traditional types of Oscillator waveforms detailed above, the UltraNova
also offers a set of carefully selected, digitally-generated waveforms containing useful
harmonic elements normally dificult to produce using traditional Oscillators.
Wavetables
A "wavetable" is essentially a group of digital waveforms. The UltraNova's 36 wavetables
each contain 9 separate digital waveforms. The beneit of a wavetable is that consecutive
waveforms in the wavetable can be blended. Some of the UltraNova's wavetables contain
waveforms with similar harmonic content, while others contain waveforms with greatly dif-
fering harmonic content. Wavetables come alive when the 'wavetable index' – the position
within the wavetable - is modulated, resulting in a sound that continually changes character,
either smoothly or abruptly.
9 Waves make up a wave table
Ring Modulation
A Ring Modulator is a sound generator that takes signals from two of the UltraNova's
osclillators and effectively "multiplies" them together. The Ultranova has 2 Ring Modulators,
one takes Osc 1 and Osc 3 as inputs, and the other takes Osc 2 and Osc 3. The resulting
output depends on the various frequencies and harmonic content present in each of the
two oscillator signals, and will consist of a series of sum and difference frequencies as well
as the frequencies present in the original signals.
OSC 1
X
OSC 3
The Mixer
To extend the range of sounds that may be produced, typical analogue synthesizers have
more than one Oscillator. By using multiple Oscillators to create a sound, it is possible
to achieve very interesting harmonic mixes. It is also possible to slightly detune individual
Oscillators against each other, which creates a very warm, 'fat' sound. The UltraNova's
Mixer allows mixing of three independent Oscillators, a separate Noise Oscillator and two
Ring Modulator sources.
OSC 1
OSC 1 VOLUME
OSC 2
OSC 2 VOLUME
OSC 3
OSC 3 VOLUME
10
1 2 3 4 5
MIXER
INPUT TO
FILTER
COMPLEX
WAVEFORM
MIX OF
OSC1, 2 AND 3
The Filter
The Ultranova is a subtractive music synthesizer. Subtractive implies that part of the sound
is subtracted somewhere in the synthesis process.
The Oscillators provide the raw waveforms with plenty of harmonic content and the Filter
section subtracts some of the harmonics in a controlled manner.
14 types of Filter are available on the UltraNova, though these are varieties of three basic
ilter types: Low Pass, Band Pass and High Pass. The type of Filter most commonly found
on synthesizers is the Low Pass type. With a Low Pass Filter, a cut-off point (or cut-off fre-
quency) is chosen and any frequencies below the point are passed, and frequencies above
are iltered out. The setting of the Filter Frequency parameter dictates the point below
which frequencies are removed. This process of removing harmonics from the waveforms
has the effect of changing the sound's character or timbre. When the Frequency parameter
is at maximum, the ilter is completely "open" and no frequencies are removed from the raw
Oscillator waveforms.
In practice, there is a gradual (rather than a sudden) reduction in the volume of the
harmonics above the cut-off point of a Low Pass Filter. How rapidly these harmonics
reduce in volume as frequency increases above the cut-off point is determined by the
Filter's slope. The slope is measured in 'volume units per octave'. Since Volume is
measured in decibels, this slope is usually quoted as so many decibels per octave
(dB/oct). Typical values are 12 dB/oct and 24 dB/oct. The higher the number, the greater
the rejection of harmonics above the cut-off point, and the more pronounced the iltering effect.
A further important parameter of the Filter is its Resonance. Frequencies at the cut-off point
may be increased in volume by the Filter Resonance control. This is useful for emphasizing
certain harmonics of the sound.
As Resonance is increased, a whistling-like quality will be introduced to the sound passing
through the ilter. When set to very high levels, Resonance actually causes the ilter to self
- oscillate whenever a signal is being passed through it. The resulting whistling tone being
produced is actually a pure sine wave, the pitch of which depends on the setting of the
Frequency knob (the ilter's cut-off point). This resonance-produced sine wave can actually
be used for some sounds as an additional sound source if wished.
The diagram below shows the response of a typical low pass ilter. Frequencies above the
cut-off point are reduced in volume.
Volume
Frequency
When resonance is added, frequencies at the cut off point are boosted in volume.
Volume
Frequency
Cutoff
Frequency
Cutoff
Frequency