hieroglyphic/plume

Plume

Hieroglyphic

A pulsar synthesizer for Eurorack based on Curtis Roads' principles, operating between oscillator, granulator, and clock generator, with stereo 96kHz/24-bit outputs, formant and cluster controls, wave shaping, folding, and output masking.1010

Capabilities 4

Granulargranular
Pulsar synthesis groups single-cycle waves into pulsars with cluster, window, and masking controls analogous to granular synthesis techniques.1010
LFOlfo
LO range extends down to sub-audio frequencies (0.5Hz–50Hz via panel knobs, 0.006Hz–6.5kHz via V/oct); suitable for LFO or clock-generator use.1010
Pulsar Synthesizerpulsar-synthesizer
Implements Curtis Roads' pulsar synthesis with formant, cluster, wave shape, fold, masking (burst and stochastic), and pulsar window controls.1010
Voltage-Controlled Oscillatorvco
Range switch selects HI mode (audio-rate VCO) or LO mode (LFO/clock); fundamental frequency set by coarse and fine knobs plus V/oct CV.1010

Jacks 11 (9 in / 2 out)

NameSignalVoltageDescription
Inputs (9)
Burst CVcv-7V to 7V1010
Cluster CVcv-7V to 7V1010
Fold CVcv-7V to 7V1010
Formant CVcv-7V to 7V1010
Shape CVcv-7V to 7V1010
SyncgateHard sync input that resets the output waveform on any rising edge above the 2.5V threshold.1010
V/Octcv-3V to 7V1010
Window Amount CVcv-7V to 7V1010
Window Type CVcv-7V to 7V1010
Outputs (2)
Output Laudio-5V to 5VLeft output; carries burst pulsars in Burst mode, or left-channel signal in Stochastic stereo mode.1010
Output Raudio-5V to 5VRight output; carries rest pulsars in Burst mode, or right-channel signal in Stochastic stereo mode.1010

Parameters 14

NameTypeRangeBehavior
AmountfaderSets the depth of the window modulation applied to each pulsar; at maximum with the rectangle window type, the output is fully muted.1010
Burstfader1 – 7In Burst masking mode, sets the count of pulsars present in the burst portion of the burst:rest loop.1010
Clusterfader1 – 7Controls the number of single-cycle waves per pulsar, continuously variable from 1 to 7; increasing cluster may affect the fundamental frequency when formant is at maximum.1010
Coarse TuneknobSets the fundamental frequency over a 10-octave range; HI mode spans 10Hz–10kHz, LO mode spans 0.5Hz–50Hz. When frequency is locked, becomes a ±2 octave switch.1010
Fine Tuneknob-6semitone – 6semitoneAdjusts the fundamental frequency by up to ±6 semitones from the centre position; deactivated when frequency lock is engaged.1010
FoldfaderApplies West-Coast-style wavefolding to the pulsar waveshape; the degree of folding is set by the slider and summed with the Fold CV input.1010
FormantfaderSets the formant frequency of the pulsar; in coupled mode the value is relative to the fundamental frequency, and in decoupled mode it is independent of it.1010
MaskbuttonSingle press toggles between Stochastic and Burst masking modes; holding for 3 seconds toggles between coupled and decoupled formant modes. Hold both Range and Mask for 5 seconds to enter calibration mode.1010
PanfaderIn Stochastic masking mode, pans the pulsar train across the stereo field.1010
ProbfaderIn Stochastic masking mode, sets the weighted probability that any given pulsar is removed from the pulsar train.1010
RangebuttonSingle press switches between HI and LO frequency ranges; holding for 3 seconds locks the frequency, disabling fine tune and making the coarse knob a ±2-octave switch. Hold both Range and Mask for 5 seconds to enter calibration mode.1010
Restfader0 – 6In Burst masking mode, sets the count of pulsars removed (muted) in the rest portion of the burst:rest ratio loop.1010
ShapefaderContinuously morphs among 7 waveforms: sine, up ramp, triangle, down ramp, square, noisy square, and white noise.1010
TypefaderMorphs among 7 window amplitude contour shapes: gaussian, exp. attack, lin. attack, triangle, lin. decay, exp. decay, rectangle. The rectangle shape acts as a reverse VCA and mutes the output when at maximum.1010

Firmware history 1 version

VersionReleasedNotes
1.1Current firmware version documented in this user guide; runs on the Electrosmith Daisy platform with web-based programmer for updates.1010

References 2

  1. [1010]
    Hieroglyphic Plume User Guidemanual
    verified 2026-05-28
  2. [1011]
    Hieroglyphic Plume product pageproduct_page
    verified 2026-05-28