26
Oscillator Drift
Displayed as: D rif t
Initial value: 0
Range of adjustment: 0 to 127
Summit has a dedicated very low frequency oscillator which can be used to apply a very
slight meandering detune to the three Oscillators. This is to emulate the oscillator drift of
traditional voltage controlled analogue synths: by applying a controlled amount of detuning,
the oscillators become slightly out of tune with each other, adding a “fuller” character to the
sound. Unlike Diverge, the drift effect changes over time.
Tuning Table
Displayed as: Tu nin gTa ble
Initial value: 0
Range of adjustment: 0 to 16
Summit normally operates with the tuning of a standard piano keyboard. The data which
relates the notes of the keyboard (or other MIDI transmitting device connected to Summit)
to the oscillator pitch intervals is called a Tuning Table: the default is Table 0, which cannot
be edited. The Tu nin gTa ble parameter lets you select one of 16 alternative tuning
tables, which you can send to Summit via Novation Components, or create yourself. See
page 26 for details of how to create a Tuning Table. Note that all 16 Tuning Tables are
initially copies of Tuning Table 0, so their effect will not be apparent until a different table
has been created.
Key Sync
Displayed as: KeySync
Initial value: Off
Range of adjustment: Off or On
With KeySync set Off, Summit’s three oscillators are free-running and even when set
accurately to the same pitch, may not be in phase with each other. This often does not
matter, but if the Ring Modulator or FM effects are in use, the out-of-phase effect may not
produce the result required. To overcome this, KeySync may be selected to On, which
ensures that the oscillators always start generating their waveforms at the start of a cycle
when a key is pressed.
Low-pass noise filter
Displayed as: NoiseLPF
Initial value: 127
Range of adjustment: 0 to 127
In addition to the three Oscillators, Summit also has a noise generator. Noise is a signal
comprising a wide range of frequencies, and is a familiar “hissing” sound. This Noise filter
is a low-pass type: restricting the bandwidth of the noise alters the characteristic of the
“hiss”, and you can adjust the filter cut-off frequency to do this. The parameter’s default
value of 127 sets the filter “fully open”. Note that the noise generator has its own input
to the mixer, and in order to hear it in isolation, its input will need to be turned up and the
oscillator inputs turned down. (See “The Mixer Section” on page 27)
High-pass noise filter
Displayed as: NoiseHPF
Initial value: 0
Range of adjustment: 0 to 127
This filter performs the same function as NoiseLPF, except that it is a high-pass filter,
and therefore as the parameter value is increased, the filter’s higher frequencies are
passed and more low-frequency content of the noise signal is rejected. The parameter’s
default value of zero sets the filter “fully open”. The effect of applying this is that each voice
will have its own tuning characteristic.
Per-Oscillator pages:
The default menu displays for Oscillator 1 are shown below:
OSCILLATOR 1 3/8
WaveMore BS sine H
FixedNote Off
BendRange +12
OSCILLATOR 1 4/8
Vsync 0 H
SawDense 0
DenseDet 64
More Waveforms
Displayed as: WaveMore
Initial value: BS sine
Range of adjustment: See list on page 45 for a list of wavetables
Summit includes an extensive set of wavetables, allowing the generation of a much broader
palette of sounds than the simple sine, triangle, sawtooth and pulse waveforms can provide
alone. Each wavetable is actually a bank of five custom waveforms, between which the
user can interpolate with the Shape control
22
. The WaveMore parameter selects
the wavetable the oscillator is to use when Wave
19
is set to more. The name of the
wavetable appears on Row 2 of the display and gives a clue as to the nature of the sound.
As with many other aspects of Summit, users will best gain an understanding of wavetables
by experimenting, and especially by adjusting the Shape control. In many cases, this will
alter the sonic nature of the selected waveform quite dramatically.
Single Fixed Note
Displayed as: FixedNote
Initial value: Off
Range of adjustment: Off, C -2 to D# 5
Some sounds need not be chromatic pitch-dependent. Examples would be certain
percussion sounds (e.g., bass drums), and sound effects, such as a laser gun. It is possible
to assign a fixed note to a patch, such that playing any key on the keyboard generates the
same sound. The pitch on which the sound is based may be any semitone note in a range
of over eight octaves. With the parameter set Off, the keyboard behaves as normal. With it
set to any other value, every key plays the sound at the pitch corresponding to the value.
Pitch Wheel Range
Displayed as: BendRange
Initial value: +12
Range of adjustment: -24 to +24
The keyboard pitch wheel can vary the pitch of each of the three oscillators by up to two
octaves, up or down: BendRange may have a different value for each oscillator. The
units are in semitones, so with the default value of +12, moving the pitch wheel up will
increase the pitch of the notes being played by one octave, and moving it down takes them
down an octave. Setting the parameter to a negative value has the effect of reversing the
operating sense of the pitch wheel. You will find that many of the factory patches either
have this parameter set to +12, giving a pitch wheel range of ±1 octave, or to +2 for a
range of 1 tone.
Try setting BendRange to different values for each of the three oscillators.
This can produce some interesting triad chords when the pitch wheel is
moved.
Oscillator Sync
Displayed as: VSync
Initial value: 0
Range of adjustment: 0 to 127
Oscillator Sync is traditionally a technique of using one oscillator (the master) to add
harmonics to another (the slave). Summit provides Oscillator Sync by implementing a
virtual oscillator for each of the three main oscillators. The virtual oscillators are not heard,
but the frequency of each is used to re-trigger that of the main oscillator. The Vsync
parameter controls the frequency offset of the virtual oscillator relative to the (audible)
main oscillator. This technique produces an interesting range of sonic effects. The nature
of the resulting sound varies as the parameter value is altered because the virtual oscillator
frequency increases in proportion to the main oscillator frequency as the parameter value
increases. When the Vsync value is a multiple of 16, the virtual oscillator frequency is a
musical harmonic of the main oscillator frequency. The overall effect is a transposition of
the oscillator that moves up the harmonic series, with values in between multiples of 16
producing more discordant effects.
OSC 2
OSC 1 (MASTER)
OSC 2 (SLAVE)
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