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Pulsar
Pulsar is a pulsar synthesizer based on the concept developed by Curtis Roads. Short packets of windowed basic waves, called "pulsarets", are emitted regularly according to an emission frequency.
- Preview display
- Burst/Channel and Stochastic masking modes
- Decoupled formant mode
- Emission sync/trigger
- CV control over most parameters
- Overlap mode with 16 max pulsars
- Polyphonic
FREQUENCY controls the emission frequency, also known as the fundamental. In the oscillator modes, it controls the rate of emission of new pulsars. When the formant is not in decoupled mode, it's also used as the base frequency for the formant.
In audio rate mode, the range is 16 Hz to 16 KHz. In low frequency mode, the range is 0.125 Hz to 128 Hz
FORMANT controls the frequency of the pulsarets.
In coupled mode, it applies an offset to the emission frequency, in 1 V/Oct. The range is -4V to 6V.
In decoupled mode, it specifies an absolute frequency. The frequency ranges are identical to the emission frequency's control.
WAVE CLUSTER determines how many cycles the base pulsaret waveform completes before it ends.
Fractional values are supported, allowing for hard sync effects.
WAVE SHAPE determines the shape of the base pulsaret waveform, crossfading between them. The shapes are, in order: Sine, Triangle, Saw, Square and Noise.
WAVE FOLD applies wavefolding to the base waveform.
WAVE AMOUNT controls how much windowing to apply to the pulsarets. At 0%, there is no windowing of the pulsaret.
WAVE SHAPE determines the shape of the window, crossfading between them. The shapes are, in order: Cosine, Linear, Exponential envelope and Logarithmic envelope.
WAVE SKEW skews the window shape. At 0%, the the window is perfectly centered, at -100%, the window has a fast attack and slow fall, and at 100%, the window has a slow attack and fast fall.
BURST (Burst count) and REST (Rest count) differ between the masking modes:
- In Burst/Channel mode, BURST determines the number of bursts, ranging from 1 to 7, while REST determines the number of rests, ranging from 0 to 7.
- In Stochastic mode, BURST determines the rest probability, while REST determines the *skip probability. Refer to the section describing the masking modes for further information.
EDGE FAC (Edge factor) controls the crossfade time when overlap mode is off. Refer to the section describing the overlap modes for further information.
MASK switches between Burst/Channel and Stochastic modes.
OVERLAP switches overlap mode on and off.
FREQ switches the emission frequency between Audio rate, Low frequency, Triggered audio rate and Triggered low frequency modes.
FORMANT switches the formant between Linked, Decoupled - Audio rate and Decoupled - Low frequency modes
All inputs are audio-rate, but new settings are only applied when a pulsaret is emitted. Currently-playing pulsarets retain the values the controls had when they were emitted.
V/OCT controls the emission frequency, following 1 V/Oct. Can be used to extend the frequency range past the limits of the emission frequency (FREQUENCY) knob.
FORMANT controls the formant frequency, following 1 V/Oct when the attenuverter is at 100%. Can be used to extend the frequency range past the limits of the formant frequency (FORMANT) knob.
SYNC hard syncs the emission, restarting the internal emission oscillator and emitting a pulsaret.
WAVE CLUSTER, WAVE SHAPE, WAVE FOLD, WINDOW AMOUNT, WINDOW SHAPE, WINDOW SKEW, BURST and REST control the controls with the same names.
MAIN outputs the pulsarets emitted as bursts.
REST outputs the pulsarets emitted as rests.
Pulsarets will not be emitted for disconnected outputs, saving processing power and pulsaret slots
The display shows the shape of the pulsaret, the emission and formant frequencies, the selected modes, and the window shape.
By default, a DC blocker is used in audio rate modes. This may be disabled in the right click menu.
In Burst/Channel mode, pulsarets will be emitted as X bursts followed by Y rests, specified by the burst count (BURST) and rest count (REST) controls.
In Stochastic mode, pulsarets will be emitted as bursts or rests randomly based on the Rest probability.
As Rest probability (BURST) increases, pulsarets will be more frequently emitted as rests.
Skip probability (REST) controls the chance for a pulsaret to not be emitted.
When overlap is off, when a new pulsaret emitted, any other currently-playing pulsarets will be crossfaded to silence. The crossfade time is controlled by the edge factor (EDGE) knob.
When the formant frequency is lower than the emission frequency, it is termed Pulsaret-Width Modulation, or "PulWM".
When overlap in on, pulsarets are allowed to overlap. There are 16 slots for pulsarets per channel, shared between bursts and rests.
When the formant frequency is lower than the emission frequency, it is termed Overlapped Pulsaret-Width Modulation, or "OPulWM".
The Audio rate and Low frequency
Audio rate ranges from 16 Hz to 16 KHz.
Low frequency ranges from 0.125 Hz to 128 Hz.
The triggered modes turn off internal pulsar emission, instead only emitting pulsarets through use of the Sync input.
In this mode, the frequency ranges and the emission frequency knob are used only as a base for the Linked formant mode.
Linked mode links the formant frequency to the emission frequency, allowing both to be controlled using only the V/Oct input, with the formant frequency knob acting as a relative V/Oct offset to the emission frequency.
The decoupled modes unlinks the formant frequency from the emission frequency, ignoring it and the V/Oct input. In this mode, the formant frequency knob acts as an absolute frequency in Hz.
Both modes use the FORMANT input, following 1 V/Oct when the attenuverter is at 100%.
- Oversampling
- Off, 2x, 4x, 8x and 16x
- Defaults to 4x
- Linear-phase oversampling (worth noting this introduces a few dozen samples of delay)
- Channel count
- Auto, and 1 through 16 channels, controls how many polyphony channels are used
- Defaults to Auto
- Display polyphony channel
- 1 through 16, controls which polyphony channel to use for the display
- Defaults to channel 1
- If the selected channel is higher than the polyphony count, defaults to channel 1
- Formant frequency display mode
- Determines how the formant frequency is shown in the display
- Auto: Determines which mode to use based on whether the formant is decoupled
- Absolute Hz: Shows the formant frequency in Hz
- Relative V/Oct: Shows the formant frequency in V/Oct, relative to the emission frequency
- Defaults to Auto
- DC blocker (Audio rate)
- When enabled, Pulsar will apply DC blockers to the outputs when in audio rate modes
- DC blocker (Low frequency)
- When enabled, Pulsar will apply DC blockers to the outputs when in low frequency modes
Pulsar:
- A pulsar consists of a burst of sound, called a pulsaret, followed by a period of silence. This total period is the fundamental or emission frequency.
Pulsaret:
- A burst of sound, made up of a basic waveform, completing a number of cycles (cluster), optionally windowed.
Window:
- A second wave, following the pulsaret's frequency, by which the base waveform is multiplied, softening the sound.
Cluster:
- The number of cycles a pulsaret completes before it ends.
Emission frequency:
- The frequency at which pulsarets are emitted. Also known as the fundamental frequency.
Formant frequency:
- The base frequency of a pulsaret, termed so because it allows for formant effects.
- Sound Composition with Pulsars, by Curtis Roads
- Microsound, by Curtis Roads