Gaussian Blur User Manual
v1.0.0
1. Description
Gaussian Blur is a stereo granular bloom reverb in two stages. The bloom stage delays, diffuses, and overlaps grains of the input, and the bloom curve sets when they are most present. The grains then feed a plate-style tail (the Plate), which sets the late decay. Part of the tail returns to the bloom, so later grains can draw on earlier reverb.
Spread controls the temporal blur: a wider range blends a broader stretch of recent sound into a more blurred, stretched texture. Density independently controls how populated the grain cloud is, from sparse fragments to continuous overlap.
Each grain starts at the same point in both channels and uses one fade, but plays its left and right channels a few cents apart. The two sides drift apart as the grain plays, which widens mono sources like a gentle chorus without panning grains to random positions. Low frequencies stay near the center while higher frequencies spread, and a sound that is only in one channel stays in that channel. Each grain also has a slight random detune, and the Plate is gently modulated, so the reverb keeps moving instead of ringing on fixed resonances. Width controls the complete wet image.
2. Main panel
The standard interface shows the bloom, tail, and tone controls on one page.
| Control | Operation |
|---|---|
| Metronome | Select the metronome to turn tempo sync on or off. The panel shows Bloom Sync when tempo sync is on. It shows Bloom Time when tempo sync is off. |
| Bloom start node | Drag the node horizontally to change Spread. |
| Bloom contour node | Drag the node horizontally to change Bias. Drag the node vertically to change Shape. |
| Default value | Double-click a knob or a value rail to restore its default value. |
On a narrow iOS screen, select BLOOM or TAIL. BLOOM shows the bloom response display and the bloom controls. TAIL shows Decay, Size, Width, Recirculate, Direction, Grain Tone, High Pass, and Low Pass.
Use this procedure to set the effect:
- Set Grain Size and Density.
- Set Bloom Time or Bloom Sync.
- Drag the bloom nodes to set Spread, Shape, and Bias.
- Set Focus, Diffusion, and Shimmer.
- Set Decay, Size, Recirculate, Direction, and Grain Tone.
- Set Width, High Pass, and Low Pass.
- Set Mix.
3. Bloom controls
| Control | Function |
|---|---|
| Bloom response display | Shows the bloom contour, the event positions, the bloom time, and the signal activity. The left node controls Spread. The contour node controls Shape and Bias. |
| Tempo Sync (metronome) | Selects the source of the bloom time. When Tempo Sync is off, Gaussian Blur uses Bloom Time. When Tempo Sync is on, Gaussian Blur uses Bloom Sync and the host tempo. Before the host supplies a tempo, Gaussian Blur uses 120 BPM. |
| Bloom Time | Sets the center time of the bloom events in milliseconds. This control is available when Tempo Sync is off. |
| Bloom Sync | Sets the bloom time as a musical note division. This control is available when Tempo Sync is on. T identifies a triplet division. D identifies a dotted division. The resulting bloom time stays between 20 ms and 5.00 s. |
| Spread | Sets the width of the event-time range around Bloom Time. Narrow settings keep the source fragments closer together in time; wider settings blend more of the recent audio into a blurred, stretched texture. Spread changes the source-time range, while Density changes grain overlap. Drag the start node to the left to increase the range, or to the right to decrease it. |
| Shape | Sets the concentration of events in the event-time range. Drag the contour node up to increase the concentration. Drag the node down to make the distribution more uniform. |
| Bias | Sets the position of the event concentration. Drag the contour node to the left to move the concentration earlier. Drag the node to the right to move the concentration later. When Shape is 0%, Bias has no effect. |
| Grain Size | Sets the duration of each grain, from 20 ms to 1 second. At a given Density, shorter grains launch more frequently and longer grains launch less frequently to maintain the target overlap. Short settings can expose more grain texture; around 200 ms is a useful starting point for a smooth cloud. Longer settings may make only a subtle difference on sustained sounds. Longer grains also spread wider in stereo, further into the low frequencies. |
| Density | Sets how many grains overlap. Low values produce a sparse cloud; high values blend more grains into a continuous texture. Around 67% targets 24 overlapping grains, and the top 18% extends the range to a target of 81. At 0%, no grains launch, but the Plate can still respond to the input. At low Density, additional filtered input and early-reflection support help establish the Plate ambience; this support fades out as Density rises through roughly 39%. Grains launch at irregular moments around the average rate rather than on a fixed pulse, so sparse settings sound scattered rather than rhythmic. At very low Density, grains can be up to 2 seconds apart. |
| Diffusion | High values soften the start of the bloom and diffuse the grain output. |
| Shimmer | Sets the probability that a new grain uses the selected Shimmer Mode. At 0%, all new grains play at the normal pitch. At 100%, every new grain is shifted. |
| Shimmer Mode | Octaves shifts every selected grain up one octave. Fifths and Octaves gives each selected grain an equal chance of playing a perfect fifth or one octave higher. |
| Focus | Changes the balance of early reflections and the main bloom. High values increase the early-reflection level and decrease the main-bloom level. Focus also reduces the small random variation in where grains read from the recent sound: 0% allows the most variation, while 100% removes that added variation. Focus does not change when grains launch. This applies throughout the Shape range and can help control the texture of shorter grains. |
4. Tail and tone controls
| Control | Function |
|---|---|
| Decay | Sets the RT60 target for the whole reverb, including the bloom and the Plate tail. RT60 is the time that the reverb level takes to decrease by 60 dB. High frequencies fade sooner, depending on Low Pass. |
| Size | Sets the delay lengths of the early reflections and the late tail. High values make more space between the reflections. |
| Width | Sets the stereo width of the complete wet reverb, including the bloom, early reflections, and Plate tail. At 0%, the wet reverb is mono. At 100%, it keeps its full stereo image. Lower settings sound denser and closer; higher settings sound more open and spacious. Width does not change the dry signal. |
| Recirculate | Increases grain-to-grain feedback before the sound passes through the Plate. Higher values regenerate recognizable material that later grains can repeat, reverse, or pitch-shift with Shimmer. Low Spread and Diffusion make separate generations easier to hear; higher settings blur them together. At 0%, only the faint background circulation remains. The Plate contributes a fixed, low-level return throughout the range. Recirculate works with Decay rather than against it: at short and medium Decay settings it extends the tail well past the Plate's own decay, and its reach narrows as Decay approaches its maximum, where the reverb is already sustaining. Decay controls how quickly the combined reverb fades. |
| Direction | Sets the playback direction chance for each newly launched grain. At -100%, every grain plays in reverse. At 0%, forward and reverse have equal probability. At +100%, every grain plays forward. Changing Direction does not alter grains that are already playing. |
| Grain Tone | Applies a bipolar low/high tilt to the summed grains before they excite the late tail. Negative values darken grain edges, fizz, and Shimmer; positive values emphasize grain brightness. At 0%, the grain signal is unchanged. |
| High Pass | Reduces frequencies below the selected frequency in the signal that enters the reverb. Increase the value to reduce low-frequency reverb. |
| Low Pass | Reduces frequencies above the selected frequency in the signal that enters the reverb. It also damps high frequencies in the coupled Grain and Plate returns. Decrease the value to reduce high-frequency reverb. |
5. Header controls
| Control | Function |
|---|---|
| Randomize (dice) | Changes the bloom, tail, and tone controls by random amounts. Mix does not change. |
| Preset selector | Shows the current preset pack and preset name. Opens the preset list. Select a preset to load its control values. |
| Menu | Opens the preset and product actions. |
| Clear | Removes the sound stored in the reverb buffers. It does not change the control values. |
| Mix | Sets the equal-power balance between the dry input and the wet reverb. |
6. Menu actions and presets
| Control | Function |
|---|---|
| Undo | Reverses the last control-value change, Randomize action, preset load, or Init action. |
| Redo | Restores the last operation that Undo reversed. |
| Grain Window | Chooses how each grain fades in and out: Tukey, Half Sine, Hann, Hamming, or Gaussian. Tukey is the default. Window differences can be subtle when many grains overlap. A new selection applies to newly launched grains; grains already playing finish with their existing window. |
| Init | Loads the initial control values. |
| Save Preset | Opens the Save Preset dialog. |
| Export User Presets | Saves the User preset pack as a ZIP file. |
Overwrite will replace the currently loaded user preset.