SpinBud is an iOS-first AUv3 rotary spatial modulation effect built around a simple model: a fixed stereo mic rig listens to up to 3 rotating speaker plates, and each plate can hold up to 3 horns. It is not a full Leslie emulation. It is a rotating emitter plus fixed stereo listener system designed for motion, width, modulation, and controllable spectral routing.
Use SpinBud on organs, synths, guitars, pads, drums, vocals, or full mixes when you want animated stereo movement that ranges from subtle cabinet bloom to aggressive multi-band spin textures.
SpinBud gives you three independent rotary layers that can each process a chosen part of the spectrum. You can run it like a classic two-way rotary cabinet, or build more experimental setups with overlapping bands, different spin rates, extra horns, and phase offsets.
SpinBud processes your input in mono for the rotating excitation path, then captures the moving result with a fixed stereo mic rig.
This matters because the effect is not just panning. Motion comes from rotating directionality, Doppler shift, off-axis tone change, horn count, phase, and mic geometry working together.
SpinBud is a single-screen instrument/effect interface.
When Plate 1, 2, or 3 is selected, the control grid shows that plate's rotary parameters.
When Mix is selected, the control grid switches to global controls for mics, room, drive, dry/wet, and output.
SpinBud works in portrait and landscape. Landscape gives the plate scene and control layout more horizontal breathing room and is usually the best editing view.
SpinBud's signal flow is straightforward and important to understand:
The plate visualizer shows the rotary system and helps you understand motion at a glance.
You can drag a plate in the visualizer to manually spin it. This is useful for performance gestures, checking motion response, and previewing how a plate reacts before settling back into motor-driven movement.
Each plate has its own independent control set.
| Control | Description |
|---|---|
| On | Enables or disables the selected plate |
| CW / CCW | Sets the rotation direction: clockwise or counter-clockwise |
| Sync | Locks plate speed to host tempo and shows the Rate control |
| Speed | Sets plate rotation speed in Hz when Sync is off |
| Rate | Sets tempo-synced rotation division when Sync is on |
| Horns | Sets horn count from 1 to 3 |
| Level | Controls the output level of that plate |
| Doppler | Sets the amount of pitch-shift motion from moving horns |
| Directivity | Narrows or widens the horn radiation pattern |
| Tone | Controls off-axis tonal darkening as horns turn away |
| Phase | Offsets the starting rotation angle in degrees |
| Wobble | Adds mechanical speed instability and motor imperfection |
| Band | Chooses a quick band preset or Custom |
| Ramp Up | Sets acceleration time into the target speed |
| Ramp Down | Sets deceleration time when slowing or stopping |
| Min Freq | Lower edge of the plate's band |
| Max Freq | Upper edge of the plate's band |
Turn plates on and off per layer. Disabling unused plates keeps the setup simpler and cleaner.
More horns create denser modulation and a richer spread. One horn feels focused and obvious. Two or three horns feel fuller and more chorus-like.
Higher values exaggerate pitch motion as horns approach and recede from the microphones. Use it carefully on wide-band material if you want to avoid seasick movement.
Higher directivity narrows the radiation beam. This usually increases amplitude motion and makes the stereo animation feel more pronounced.
This sets how much the sound darkens off axis. Higher values make the rotating pattern feel more speaker-like and less flat.
Phase is especially powerful when multiple plates overlap in frequency. Small offsets create moving complexity. Larger offsets can produce dramatic stereo reshaping.
Wobble adds mechanical jitter. Low settings add life. High settings produce unstable, broken, or woozy motion.
These controls shape how fast a plate reaches its new motor speed. Longer ramps are good for chorale-to-tremolo transitions and brake effects.
Each plate can process a different part of the spectrum. This is the core of SpinBud's multi-plate design.
| Band Preset | Frequency Range |
|---|---|
| Sub | 20 Hz to 80 Hz |
| Low | 20 Hz to 180 Hz |
| Bass | 60 Hz to 300 Hz |
| Body | 120 Hz to 900 Hz |
| Mid | 500 Hz to 2200 Hz |
| Hi-Mid | 2000 Hz to 8000 Hz |
| Presence | 1500 Hz to 6000 Hz |
| Treble | 5000 Hz to 20000 Hz |
| High | 8000 Hz to 20000 Hz |
| Air | 4000 Hz to 20000 Hz |
| Full | 20 Hz to 20000 Hz |
| Custom | Manual min and max values |
The lower spectrum area shows real-time frequency activity and helps you see where energy is landing while you define bands. Colored regions indicate the assigned ranges for the plates.
If you move Min Freq or Max Freq manually, the Band selector becomes Custom.
The Mix page contains the global controls shared by all plates.
| Control | Description |
|---|---|
| Angle | Rotates the stereo mic pair around the rotor field |
| Spread | Sets the angular distance between left and right mics |
| Mic L | Sets the left mic distance from the center |
| Mic R | Sets the right mic distance from the center |
| Room | Adds cabinet or room bloom to the summed wet signal |
| Drive | Applies input drive before rotary processing |
| Dry/Wet | Blends original signal with processed signal |
| Master | Sets final output gain |
The mic rig is global. All plates are heard through the same left and right microphone layout.
Changing mic geometry can be as important as changing plate speed. Small asymmetries often create more natural width than perfectly symmetrical settings.
Room adds indirect cabinet-style ambience around the summed wet signal. It does not affect the individual plate stem buses.
Drive pushes the mono excitation signal before rotary processing. A little drive can help organs and synths speak more clearly. Too much drive can flatten delicate motion, so rebalance with Master.
Use 100% wet for insert-style rotary effects when the host already manages dry signal, or when you want to use SpinBud's plate stems separately. Use lower values when you want to preserve more of the original source.
SpinBud supports both free-running motor speeds and host-synced rhythmic speeds.
When Sync is off, each plate speed is set directly in Hz. This is best for cabinet-style behavior and sound design where physical speed matters more than beat alignment.
When Sync is on, SpinBud converts the chosen note division into a rotation speed based on the current host tempo.
This is useful when:
Ramp Up and Ramp Down still matter in synced setups. They determine how the plate settles into its new target speed after a change.
SpinBud includes factory presets that cover classic cabinet references and more exaggerated motion textures.
Load the closest preset, then adjust these first:
SpinBud supports user presets in addition to the factory bank.
This makes it practical to keep project-specific setups, cabinet-style favorites, and host-routing templates.
In standalone mode, SpinBud includes MIDI note control for plate gestures.
MIDI note input can flick individual plates with a gesture-derived spin impulse. This is a performance feature, not a full keyboard instrument mapping.
Velocity affects the strength of the flick gesture. Higher velocity creates a faster spin impulse.
The Settings view lets you change:
The settings page also provides access to the built-in tutorial and app information.
SpinBud can run as an AUv3 effect in compatible hosts and exposes multiple stereo outputs.
| Bus | Content |
|---|---|
| Bus 0 | Main stereo output: dry/wet mix plus room and output gain |
| Bus 1 | Plate 1 wet stereo stem |
| Bus 2 | Plate 2 wet stereo stem |
| Bus 3 | Plate 3 wet stereo stem |
The per-plate outputs let you:
How multi-out routing appears depends on the host. In hosts that support AUv3 multi-out, instantiate SpinBud on a compatible effect slot and enable its extra outputs or return buses from the host's channel routing page.
Common uses:
If a setup feels messy, simplify first: use two plates, separate their bands clearly, set sensible speeds, and only then add phase offsets, extra horns, or heavy wobble.