User Manual

19
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). Peak provides Oscillator Sync by using 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)
Vsync may be controlled for any or all oscillators using the Modulation
Matrix. See “The Modulation Matrix” on page 26 for details of how to
use the Matrix.
To get the best out of Vsync, try modulating it using the LFO. Try assigning
it to the MOD wheel for real-time control.
Sawtooth Density
Displayed as: SawDense
Initial value: 0
Range of adjustment: 0 to 127
This parameter only affects sawtooth waveforms. It effectively adds copies of the oscillator
waveform to itself. Two additional virtual oscillators are used for this, producing a “thicker”
sound at low to medium values, but if the virtual oscillators are detuned slightly (see
Density Detuning below), a more interesting effect is obtained.
Density Detuning
Displayed as: DenseDet
Initial value: 64
Range of adjustment: 0 to 127
This parameter should be used in conjunction with Sawtooth Density. It detunes the virtual
density oscillators, and you will notice not only a thicker sound, but the effect of beating as
well.
Sawtooth Density and Density Detuning parameters can be used to
“thicken” the sound, and simulate the effect of adding additional Voices.
The Unison and Unison Detune parameters in the Voice Menu can be used
to create a very similar effect, but using Density and Density Detune have
the advantage of not needing to use additional Voices, which are finite in
number.
Common Oscillator page:
The default menu display is shown below:
OSC COMN 1 1/8
Diverge 0 h
Drift 0
Noise 127
OSC COMN 2 2/8
KeySync Off h
Diverge
Displayed as: Diverge
Initial value: 0
Range of adjustment: 0 to 127
Peak is an eight-voice synth, and each voice has three oscillators. Diverge applies very
small pitch variations independently to each of these 24 oscillators. The effect of applying
this is that each voice will have its own tuning characteristic. This adds a further interesting
colouration to the sound quality and can be used to bring the synth alive. The parameter
sets the degree of variation.
Oscillator Drift
Displayed as: D rift
Initial value: 0
Range of adjustment: 0 to 127
Peak 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 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.
Noise filter
Displayed as: NoiseLPF
Initial value: 127
Range of adjustment: 0 to 127
In addition to the three Oscillators, Peak also has a noise generator. Noise is a signal
comprising a wide range of frequencies, and is a familiar “hissing” sound. The Noise filter
is a low-pass type: restricting the bandwidth of the noise alters the characteristic of the
“hiss”, and you can adjusting 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 22.)
Key Sync
Displayed as: KeySync
Initial value: Off
Range of adjustment: Off or On
With KeySync set Off, Peak’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 is 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.