Pulsar Hell

Sound is a train of pulsars: brief events emitted at a controllable rate. Each pulsar has two parts. The pulsaret is a waveform that loops inside the grain. The envelope plays once and sets the grain's length and shape. The output is their product.

Fund freq sets how often grains fire; in the audio range they fuse into a pitched tone. Formant sets how fast the pulsaret is scanned inside each grain, so tone color moves independently of pitch.

Grain length is 1 / (fund × formant × env) seconds, and each grain holds about 1 / env pulsaret cycles. At ENV 1.0 the pulsaret is read through exactly once per grain.

Pulsar Hell runs four complete pulsar trains, PULSAR 1 to 4. All four sound at the same time; the tabs only choose which one you view and edit. Trains never affect each other in the engine. They meet only at the mixer.

Each train has its own pulsaret and envelope, fundamental, modulation matrix, FM and flux, masking, Fourier and wavelet state, sieve pattern and channel routing.

Three groups per train

Inside a train, three independent groups scan the same pulsaret and envelope. Each sets its own FORM, ENV, PULSE, PAN and AMP. The groups are not linked or synced, so one train layers three formant-shaped voices from one source.

Masking and modulation

Every trigger passes three gates in order: probability, then burst and rest, then the sieve pattern. A rejected trigger silences all three groups.

FM sets each grain's playback rate at the moment it spawns, so pitch varies across grains rather than within them. Mode B subtracts instead of multiplies, and grain rates can go negative for backward playback. FLUX adds random jitter to density and pitch.

Every train reads one pulsaret and one envelope, both wavetables of 2048 samples. 912 factory wavetables in 31 categories, including Analog, Chaos, FOF, Glottal, Oto, Superformula and Window. A browser with search and waveform thumbnails loads a table on click.

Your own WAV, AIFF and FLAC files load as wavetables. Up to 65,536 samples are read and resampled to 2048 with linear interpolation, loaded as they are: no normalization, no DC removal. Originals are never modified.

Draw directly on the canvas, or apply transforms. Transforms accumulate, so their order matters. Lock keeps a table when you load presets. Save writes it to your User folder.

Editor transforms

Four modulators, M1 to M4, route to 14 targets: Fund, FORM 1 to 3, ENV 1 to 3, PAN 1 to 3, AMP 1 to 3 and PROB. Click a cell to connect. One modulator can drive many targets, and several can sum onto one. Each has a rate from 0.001 to 150 Hz and a depth from 0 to 10.

Types are Sine, Saw, Square, Triangle, S&H, and four chaotic or stochastic sources: Latoocarfian, Gendy, Henon and Lorenz. Modulation is bipolar for fundamental, formant and envelope, attenuating for pan and probability, and multiplicative for amplitude.

A separate loop engine reads wavetables as automation curves. It sweeps over 0.3 to 120 seconds in Forward, Reverse, PingPong, Random or Drunk direction, and modulates fundamental, probability, FM, flux and the per-group parameters.

An additive editor that builds the pulsaret from 32 harmonics. Draw amplitude and phase by hand, with a preview of the waveform as you go. Turning it on captures the current pulsaret and renders the spectrum into it; turning it off restores the captured table, so you can compare without losing the original.

Generators replace the spectrum. Modifiers such as Decay, Thin, Scatter and Rotate reshape it. In Phase mode, presets redistribute phase without changing the amplitude spectrum. STR pushes partials off integer ratios, TILT brightens or darkens, and each can cycle on its own triangle LFO from 0.5 to 30 seconds.

Amplitude generators

Phase presets

A step sequencer based on Xenakis sieve theory, which builds rhythms from residue classes rather than by hand. The pattern is the third masking gate, after probability and burst and rest. With the sieve on, each trigger consumes one step. Grains fire only on active steps.

Length of 8, 16 or 32 steps. Euclid spaces hits evenly, Sieve builds a structured pattern at the chosen density, Rnd fills at random. Inv and Clr invert or clear. Any step can be edited by hand. A circular view draws the same pattern around a ring, which shows its rotational symmetry.

A discrete wavelet transform stage. Grain DWT processes the train's output in fixed 1024-sample frames, decomposing with one wavelet and reconstructing with another; the mismatch recolors the sound. With Cycling on, each trigger advances one entry through the analysis and synthesis lists.

Stream DWT processes the continuous output in buffers of 256 to 4096 samples, with ten coefficient operations including Bin Rotation, Magnitude Freeze, Per-Scale EQ, Scale Swap and Threshold Gate. The library holds more than 50 wavelets across the Daubechies, Haar, B-spline and Coiflet families.

Morph is per train. Each train crossfades between two captured snapshots of its own, Set A and Set B, with its own Cycle and Rate; the cycle period runs from 0.1 to 60 seconds. Morphing one train never affects another.

Loading a preset clears that train's snapshots. Morph never touches the mixer or the power buttons: master volume, mute and limiter, and every train's Level, mute, limiter and Enable stay under your control throughout.

The output bus has 8 discrete channels with no fixed speaker assignment. Each train chooses its own channel count on the mixer: 2, 3, 4, 6 or 8.

Grains are placed around a ring of channels with equal-power panning. CH MASK cycles successive grains through positions, and the four trains sum channel for channel.

Mixer

Each strip has a level fader, mute, solo, and per-channel peak meters with peak hold. The master section adds global volume, mute, and a lookahead limiter that is off by default.

In Reaper, raise the track's channel count to 8. To send channels to another application, route through a virtual multichannel device such as Loopback.

The whole instrument lives in one fixed window: top bar, three columns, and the mixer. The right column switches between five tabs; the window itself is at the top of this page.

TablesMatrixFourierPatternWavelet

Pulsar Hell is a macOS product. All three formats share the same engine, presets and wavetables.

Install locations and content folders: Support →

Pulsar Hell is not released yet. It is $150 USD, and pre-orders open before release. Payment is handled by Lemon Squeezy as merchant of record, and licence terms are set out in the end user licence agreement. Refunds are covered by the refund policy.