iOS Manual

1. Thank You

Thank you for purchasing VMEGAfm. A great deal of care, love, and close listening went into creating this instrument, and we hope that passion comes through every time you play it.

VMEGAfm for iPad contains two closely related instruments in one installation:

Both interface modes use the same four-operator, sine-only FM instrument. They share factory sounds, user presets, global preferences, and synthesis behavior.

The sound engine recreates the original MEGAfm character from its schematics, source code, and listening tests with real hardware, including its compression, saturation, and fuzzy output behavior.

VMEGAfm is also available for macOS and Windows as a standalone instrument and DAW plug-in. Installation and desktop-specific operation are covered in the separate desktop manual.

2. System Requirements

Older supported iPads can run VMEGAfm, but a busy host session may need a larger audio buffer or fewer simultaneous instruments and effects.

3. Installation and Opening the AUv3

Install the app

1. Install VMEGAfm from its authorized distribution source.
2. Launch the VMEGAfm app once so iPadOS can make the AUv3 instrument available to compatible music apps.
3. Keep the iPad in landscape orientation for the full-screen app.

GarageBand for iPad

1. Open or create a GarageBand song.
2. In the Sound browser, swipe to External.
3. Tap Audio Unit Extensions.
4. Select VMEGAfm. GarageBand creates an instrument track and provides its own keyboard, transport, recording, and track controls around the compact VMEGAfm editor.

Apple documents this workflow in Use other music apps with GarageBand for iPad. GarageBand wording and button placement may change between releases.

Other AUv3 hosts

Add VMEGAfm as an instrument or music device, not as an effect. Route MIDI to it and connect its stereo output to the host mixer. Hosts differ in how they expose plug-in windows, MIDI clock, MPE, preset snapshots, and file access.

4. Full-Screen App vs Hosted AUv3

5. Quick Start

Full-screen app

1. Launch VMEGAfm in landscape.
2. Select a factory sound from the top-left factory browser. A fresh installation starts on Time To Rain.
3. Play the onscreen keyboard.
4. Move operator Total Level and Multiply faders, then try a different algorithm.
5. Press write and name the patch when you want to keep it.

GarageBand or another host

1. Add VMEGAfm as an AUv3 instrument and open its custom view.
2. Choose a factory preset in VMEGAfm's own top bar.
3. Compact layout starts on voice; choose classic layout in Settings when the host provides enough space.
4. Use op1-2 and op3-4 to shape the sound.
5. Use lfo for movement, and the far-right Link 1/2/3 tabs to connect the last-touched control.
6. Record MIDI in the host. Save the host song for complete instance recall; use VMEGAfm Write for a portable user preset.

6. Touch Interaction

VMEGAfm uses enlarged invisible hit areas around compact knobs and faders, especially in the hosted interface. The visible controls do not overlap, while their touch zones fill as much free space as possible.

Knob

Touch and drag vertically. Hosted controls remain smooth and responsive even during vigorous movement.

Fader

Touch near the fader and drag vertically. The hosted fader hit area is wider than the drawn track.

Algorithm

Tap an algorithm LED/drawing directly, or drag the Algorithm knob.

Voicing

On the Voice tab, tap the text Poly12, Wide6, or Unison. The labels are invisible-button hitboxes; the LED shows the selection.

Tune center

Double-tap the Global Tune or Preset Tune slider to return to zero.

Preset browser

Scroll by dragging. A preset loads only when touch-down and touch-up complete without becoming a scroll gesture.

Ghost faders and knobs show the effective LFO-modulated position while the normal control remains at its stored base value. A blue halo appears around the current CC Learn target only while CC Learn is active.

7. Presets and Shared User Banks

Factory and user browsers

The Factory browser contains built-in, read-only sounds. The User browser contains sounds you write or import. Both browsers are drawn inside VMEGAfm, so they remain visible and touch-safe even when GarageBand does not display native plug-in pop-up menus correctly.

A fresh installation or new AUv3 instance with no restored state starts on Time To Rain. Saved app or host state takes priority afterward. Tap Reset to load 01 Clean(ish) Sine; hold it for two seconds to vary the current patch, then keep holding for progressively wider changes. A randomly tinted panel light sweep confirms each variation.

VMEGAfm includes 100 core factory presets covering electronic keys, basses, leads, mallets, pads, movement, sequences, percussion, and experimental effects. Ten additional MPE presets appear when MPE is enabled.

Factory presets are grouped by category. The MPE category contains 10 additional expressive presets and appears only when MPE mode is enabled, after 01 Clean(ish) Sine. Turning MPE off hides the category without removing its sounds. User presets can also be tagged by category when saved; empty categories are hidden from the browser, and the MPE tag is shown only while MPE is on.

Top-bar actions

Write

Names and stores the current sound in the shared user bank. A matching existing name is updated.

Delete

Deletes the currently selected user preset after confirmation. Factory entries cannot be deleted.

Import

Uses the iPad document picker to read a VMEGAfm XML user bank or an original MEGAfm .syx bank.

Export

Uses the document picker/share flow to save the complete user bank as XML.

Add or replace

Import asks whether to add the chosen bank to My Presets or replace the current bank. Original MEGAfm SYX banks are translated to VMEGAfm's direct ADSR controls; recognized Limbic banks keep their MAGNITUDE or PARSEC names and categories. The first imported sound loads immediately and is highlighted. Export before Replace if the current bank matters.

Sharing between the app and AUv3

The full-screen app and AUv3 instrument share the same VMEGAfm user-preset library. A preset written in the app becomes available in GarageBand, and a preset written in GarageBand becomes available in the app. If a browser was already open, close and reopen it or reopen the plug-in to refresh the list.

The host's own Presets or Save Sound feature stores a host-specific snapshot. VMEGAfm Write stores a VMEGAfm user preset that can be exported and used in other hosts. Both are useful, but they are not the same library.

8. Full-Screen Interface

The full-screen panel closely matches the desktop standalone application. Its header and major sections stay in fixed positions so it reads like an instrument rather than a collection of pages.

Header

Factory / User

Open the built-in preset browsers.

Write / Delete

Create or remove user presets.

Import / Export

Exchange XML user banks or import original MEGAfm SYX banks through the iPad document picker.

Settings

Opens the global settings overlay.

Links

Scrolls the complete panel upward to reveal the full modulation matrix, then returns to the main panel when closed.

CC Learn

Shows controller assignments over learnable knobs/faders and accepts an incoming standard MIDI CC for the selected target.

Hold

Applies sustain to the onscreen keyboard.

Manual icon

Opens the iOS manual in the browser.

Main panel sections

• Global: algorithm knob/drawings, feedback, display, preset navigation/reset, and reverb flap.
• Operators 1-4: Total Level, Multiply, Attack, Decay, Sustain, and Release faders.
• LFO 1-3: Rate, Depth, select/link buttons, waveform, Retrig, and Loop. The printed LFO labels change to velocity, mod wheel, slide, aftertouch, or pressure when a bus is overridden.
• Arp: Mode, Rate, Range, and Rec.
• Vibrato: Rate and Depth.
• Voicing: Poly12, Wide6, Unison, Fat, Glide, and Volume.
• Keyboard: octave movement, Hold, multitouch notes, and optional Slide.

Display behavior

• The active factory or user preset index returns to the display after temporary value feedback.
• Algorithm, feedback, ratios, envelope values, rate choices, and mode changes briefly use the display.
• Velocity, mod wheel, aftertouch, pressure, and Slide override labels appear during deliberate edits, not during a preset load.
• The selected LFO waveform LED remains on and glows brighter with LFO intensity.
• Moving an operator fader temporarily changes the LFO LED cluster into the operator envelope-loop display.

9. Hosted AUv3 Interface

Hosted AUv3 offers two layouts with the same sound engine. Use Settings > Display mode to toggle them; the choice is remembered.

• Compact layout: fixed tabbed pages designed for GarageBand and short plug-in windows.
• Classic layout: the complete hardware-style panel without the onscreen keyboard, intended for larger AUM, Loopy Pro, and similar host windows.

Both layouts stay anchored at the top-left. When a host makes the window smaller than the reference layout, VMEGAfm crops rather than crushing controls together; use the subtle bottom and right scrollbars to reach the hidden area.

Compact top bar

From left to right, the bar contains Factory, User, Write, Delete, Import, Export, Voice, Op1-2, Op3-4, LFO, Settings, and three numbered Link tabs. The Link 1/2/3 tabs refer to the last knob or fader you touched:

• An inactive link tab has a dark body with a white outline, white chain icon, and white number.
• An active assignment fills warm white; its chain icon and number become dark so they remain legible.
• The link tabs are static status controls. They do not pulse with the LFO waveform.
• Tap a link tab to toggle the current control's assignment to that LFO. A disabled tab means the requested self-link is not legal.

Classic layout

Classic layout presents all four operators, LFOs, arp, vibrato, voicing, reverb, Links, and CC Learn together. The reverb flap is directly above the Feedback knob: tap the blue REVERB label to open the flap and reveal Mix and Size, then tap it again to close it. Classic layout intentionally omits the built-in keyboard because the host supplies MIDI notes. The full panel may be cropped in a small host window, but its control spacing does not change.

Voice tab

Op1-2 and Op3-4 tabs

Each page shows two operators and uses the vertical space for 12 large fader lanes: six per operator.

Above the faders, both operator tabs show Algorithm, the eight algorithm diagrams/LEDs, Feedback, and a dedicated Loop button/LED for each visible operator. Tap an algorithm LED/drawing directly. Loop buttons are momentary; their separate LED shows state and does not latch the button artwork.

LFO tab

The top row contains six shape/action buttons and LEDs: Square, Triangle, Saw, Noise, Retrig, and Loop. Below are three framed Rate/Depth pairs. An activity LED between each pair shows that LFO's instantaneous value. The Links shortcut opens the routing matrix without consuming top-bar width.

When MPE or another mapping overrides an LFO bus, the label changes to the active source. With MPE pressure enabled, LFO3 is labeled Pressure. With MPE slide enabled, LFO2 is labeled Slide. Turning those switches off restores the normal LFO labels and behavior.

Links page

The Links page has four subtabs in this order: voice, op1-2, op3-4, and lfo. Every parameter row has cells 1, 2, and 3 for the three LFOs. Off cells are neutral gray; active cells are warm white. An LFO's own Rate and Depth cells are disabled for that LFO.

• Voice: Algorithm, Feedback, Fat, Arp Rate, Arp Range, Reverb Mix, Reverb Size.
• Op1-2: Total Level, Multiply, Attack, Decay, Sustain, and Release for operators 1 and 2.
• Op3-4: The same rows for operators 3 and 4.
• LFO: LFO 1-3 Rate/Depth plus Vibrato Rate/Depth.

10. How Four-Operator FM Works

Each of the four operators is a sine oscillator with its own ratio, output level, and envelope. An audible operator is a carrier. An operator that changes another operator's frequency is a modulator. The algorithm selects the routing; operator 1 owns feedback.

Increasing a carrier level raises its contribution to loudness. Increasing a modulator level raises modulation index and therefore spectral brightness or complexity. In a chain, a fast-decaying modulator over a slower carrier is a reliable way to create an acoustic-style attack.

Multiply and Feedback

Multiply offers 0.5 and integer ratios 1-15. Harmonic integer relationships produce stable pitched sounds; high or widely separated ratios produce tines, bells, metal, and effects. The curated VMEGAfm patch convention often uses displayed Multiply 4 for the principal carrier and chooses other ratios relative to it.

Feedback sends operator 1 into itself. Small amounts add harmonics; high amounts can become raspy or noisy, particularly when operator 1 is deep in a modulation chain. Feedback is especially effective for percussion and special effects.

11. Operators, Custom ADSR, and Envelope Loops

Core operator controls

VMEGAfm translates the YM2612's multi-rate envelope system into direct Attack, Decay, Sustain, and Release controls. The timing remains characterful, but programming is faster and easier than the original register-level workflow.

For a piano, bell, mallet, or pluck, set Sustain to zero and use Decay for the natural tail. For an organ, pad, brass, or drone, use a nonzero Sustain. A modulator can have a shorter decay than the carrier to create a bright transient that settles.

Operator looping in the full-screen app

1. Move any fader belonging to an operator.
2. For about two seconds, the LFO shape/retrig/loop cluster displays that operator's envelope-loop state.
3. If the operator loop is enabled, the Loop LED pulses at 3 Hz.
4. Tap Loop during this period to toggle the focused operator.

Operator looping in hosted mode

Op1-2 provides Loop1 and Loop2; Op3-4 provides Loop3 and Loop4. Tap once to toggle. The button remains visually momentary and the separate LED carries the persistent state. A looping operator cycles Attack, Decay, Sustain, and Release while the key remains held.

12. Voice and Performance

MPE uses the 12 channels as independent member lanes and temporarily bypasses normal Poly12/Wide6/Unison allocation. The previous normal mode returns when MPE is disabled.

13. LFOs, Quick Links, and the Link Matrix

There are three independent modulation buses. Each can use Square, Triangle, Saw, or Noise; can retrigger per note; can run once or loop; and can connect to many parameters at the same time. A bus can also be replaced by an input source such as velocity, mod wheel, aftertouch, MPE pressure, or slide.

LFO controls

The printed labels above the LFO controls are contextual. They show LFO1, LFO2, and LFO3 when the internal oscillators are active. They change to velocity, mod wheel, aftertouch, slide, or pressure when a bus is being driven by that external expression source.

Link rules

• Move a knob/fader first, then use Link 1/2/3 to connect it in hosted mode.
• In the full-screen app, move a target and use the LFO 1/2/3 select/link buttons, or edit the complete Links page.
• A parameter can receive more than one LFO. Their signed changes add together.
• The result clips at the parameter minimum/maximum and never wraps around.
• An LFO cannot modulate its own Rate or Depth. The relevant cell/tab is disabled.
• Reverb Mix and Size use their full meaningful ranges when modulated, just like other knobs.

Visual feedback

The full-screen panel brightens the selected waveform LED with the LFO value. The hosted LFO page instead has one activity LED between each Rate/Depth pair. Hosted Link 1/2/3 tabs report assignments; they do not pulse with the waveform.

On either main interface, a translucent ghost or halo follows the modulated effective knob/fader position. The normal control remains at the base value so you can see the center of modulation. In MPE mode, operator-linked expression is polyphonic; the visible ghost follows the currently focused expressive voice and slews between voices so it remains readable.

14. Arpeggiator and Step Sequencer

The arp captures held notes when a mode other than Off is selected and Rate is above zero. Range spans one to four octaves. In the full-screen app, a short press of Mode cycles through the active modes; hold Mode for about two seconds to switch the arp Off. In either AUv3 layout, tap the Mode control to open a direct list with Off as its first item.

Record a sequence

1. Tap rec. The Rec LED indicates recording and the old sequence is cleared.
2. Play notes in the required order. The first note becomes the reference; later notes are stored as semitone offsets so the pattern transposes.
3. In the full-screen app, use preset-up to insert a rest and preset-down to remove the last step.
4. Record up to 16 steps.
5. Tap Rec again to finish, then choose Seq or Seq Hold.

Sequence recording is disabled under MPE. Arp Sync follows host/MIDI clock. Retrig-enabled LFOs restart for each generated arp note, which is useful for repeatable rhythmic timbre envelopes.

15. Reverb and Output

Mix

Plate reverb dry/wet amount from 0% to 100%.

Size

Plate size/decay time from approximately 0.2 to 10.0 seconds.

No Reverb

Global bypass in Settings. It ramps the wet path cleanly, keeps the full-screen flap shut, and hides the hosted Mix/Size frame without erasing its stored values.

Vol

Patch output level and drive into the character stage.

In the full-screen app and hosted Classic layout, the reverb flap sits directly above the Feedback knob. Tap the blue REVERB label to open it and reveal Mix and Size; tap it again to close it. In hosted Compact layout there is no flap: open the Voice tab and use Mix and Size in its Reverb frame. Reverb parameters are saved with each sound; No Reverb is a global preference.

Automatic level control keeps the output strong and helps prevent unwanted digital clipping. There are no additional controls to set.

16. Full-Screen Keyboard

The built-in keyboard is available only in the full-screen app. Settings switches it between 3 octaves and 2 octaves; 3 octaves is the default. Its octave position is remembered.

Arrow buttons

Shift the visible range one octave at a time.

Two-finger horizontal drag

Scrolls the keyboard without playing notes. Existing notes are released when two-finger scrolling starts.

Hold

Applies sustain-pedal behavior to touchscreen notes.

Slide

With Slide > LFO2 enabled, vertical key position sends a per-note Slide value: top is 127, bottom is 0.

Range

MIDI notes 12-96, displayed as C0-C7. The visible span is 24 or 36 semitones.

Slide is polyphonic for linked operator parameters: moving one finger vertically affects that finger's voice. Parameters that are global by nature, such as Algorithm or Reverb, remain global even when driven from the latest expression lane.

17. Settings Reference

The full-screen app uses a three-column overlay. Compact hosted mode divides settings into control, tuning, lfo sync, and lfo map tabs. Classic hosted mode uses the larger overlay.

Control

Tuning

Closing Settings automatically turns off the 440 Hz tone and releases Play A4. Compact hosted mode places both references in one split row to save space. The host and iPadOS control the audio route.

LFO sync

LFO map

Velocity, Mod, Aftertouch, Pressure, and Slide mappings override the normal waveform of their assigned bus rather than adding another LFO. Depth still determines the maximum amount and the Link matrix still determines destinations. When a bus is overridden, its Rate knob is greyed out and its sync switch is hidden because the external source supplies the movement.

18. Shake to Shuffle

Shake to Shuffle makes small variations rather than replacing a patch. Each affected parameter moves by no more than about 5% and remains inside its valid range. Gentle movement requires two impulses; a stronger deliberate shake registers once, followed by a short cooldown.

A randomly tinted light sweep confirms the change. Shake starts Off on every launch to prevent accidental edits.

Scope

Shake clears the current factory/user selection because the result is now a modified patch. Use Write immediately if a variation is worth keeping.

19. MIDI, MPE, CC Learn, and Host Automation

Hosted MIDI

In GarageBand, the host keyboard, recorded regions, sustain, transport, and external MIDI routing are supplied by GarageBand. VMEGAfm receives the events delivered to its instrument track. Other hosts may provide channel filters, MIDI processors, clock settings, and MPE routing.

MPE

VMEGAfm accepts a standard lower-zone MPE setup with master channel 1 and member channels 2-16. It maps the first 12 active touches onto its 12 synthesis voices automatically, so controllers can retain their normal lower-zone channel range. It supports per-note pitch bend at ±48 semitones.

Ten curated MPE factory presets become available when MPE is enabled. Their category appears directly after 01 Clean(ish) Sine in the factory browser and is hidden again when MPE is turned off. The presets remain installed; the conditional category simply keeps ordinary browsing uncluttered. These sounds demonstrate per-note bend, Pressure, Slide, and combinations of those gestures.

When MPE is on, Pressure and Slide buttons appear beside the MPE switch. Pressure routes member-channel pressure through LFO3. Slide routes MPE CC74 through LFO2. Turn either button off to return that bus to normal LFO behavior. Velocity > LFO1 remains available while MPE is on, so velocity, slide, and pressure can be combined.

Operator destinations respond per voice. Global destinations such as Algorithm, Feedback, Vibrato, Reverb, and Arp controls use the highest active expression value across the held voices, with smoothing so the visible ghost and audible result do not jump harshly when focus changes.

MPE temporarily disables normal Poly12/Wide6/Unison selection and Fat because each played note already owns an independent expression lane. MPE only works when the host preserves and routes member-channel expression. If notes disappear or expression becomes monophonic, test with MPE off, then check the host/controller's lower-zone channel range and track routing.

CC Learn

1. Connect or route a MIDI controller to the standalone app.
2. Tap cc learn.
3. Tap a knob or fader. Its target halo pulses blue.
4. Move a controller sending standard CC 1-127 with a value above zero.
5. The number appears over the target. Tap the small x beneath an assigned number to remove that mapping, or repeat to learn another control.

Value 1 maps to minimum and 127 to maximum; 0 is ignored. The reverb flap opens temporarily so Mix/Size can be assigned. CC Learn can target controls greyed by MPE or another override. It is available in the full-screen app and Classic hosted layout; Compact hosted users can use host MIDI mapping.

Host automation moves the base value. LFO modulation then moves around that base and clips at minimum/maximum. Automation, host presets, and GarageBand regions are saved by the host song rather than by VMEGAfm's XML user bank.

20. Performance and Latency

GarageBand and other hosts share the iPad's available performance across every instrument, effect, and track. VMEGAfm uses one fixed hardware-modeling path on iOS and paces visual feedback separately to help playback remain stable; no output-quality setup is required.

If audio crackles

• Stop touching a rapidly modulated control and check whether the host is close to its session limit.
• Freeze/bounce other instruments or disable unneeded effects.
• Reduce long reverb and dense 12-note chords while testing.
• Close background audio apps and reconnect a stable wired audio interface if the current route is unreliable.
• Test the same patch in the full-screen app. If it is clean there, the issue is likely total host-session load or buffer pressure.

21. State, Storage, and the Files App

Deleting VMEGAfm can remove locally stored settings and user presets. Export the user bank before deleting or reinstalling the app, or before moving to another iPad. A host song is not a substitute for an exported portable bank.

22. Troubleshooting

VMEGAfm is not listed in GarageBand

• Launch the standalone VMEGAfm app once.
• Quit and reopen GarageBand.
• Restart the iPad if Audio Unit registration has not refreshed.
• Confirm iPadOS 15 or later and that VMEGAfm has not been offloaded.
• In GarageBand, add it from External > Audio Unit Extensions as an instrument.

Factory names are visible but the patch does not change

• Complete a tap without scrolling; a drag is treated as browser navigation and intentionally does not load.
• Check whether host automation immediately writes old values back over the new preset.
• Close/reopen the AUv3 view and test factory 01 versus a dramatically different sound.
• Restart the host if its open VMEGAfm window does not refresh after reinstalling the app.

User presets differ between the full-screen app and hosted version

• Close and reopen the preset browser so it refreshes the shared VMEGAfm library.
• Close/reopen the host if the extension was already running when the bank changed.
• Export an XML backup before troubleshooting a replace/import operation.

Notes are missed in GarageBand

• Test MPE off first. A mismatched MPE zone can look like missing notes.
• Check the GarageBand track keyboard range, scale/chord mode, sustain, and MIDI input route.
• Reduce session CPU load and test with 01 Clean(ish) Sine.
• Confirm the arp Rate is not zero when an arp mode is selected.

I cannot find the reverb controls

In the full-screen app or hosted Classic layout, look directly above the Feedback knob and tap the blue REVERB label to open the flap. In hosted Compact layout, open the Voice tab; Mix and Size are in its Reverb frame. If neither location is available, No Reverb is on: turn it off in Settings to release the flap or restore the Compact Reverb frame.

The screen is locked to landscape

This is intentional for the full-screen app. The panel is not designed for portrait. A host controls its own surrounding orientation, but VMEGAfm's Compact editor remains arranged for a wide instrument view.

The 440 Hz tone continues

Tap the tone button again or close Settings. VMEGAfm stops both tuning sources automatically when leaving Settings.

23. Glossary

AUv3

Apple's Audio Unit plug-in format used by VMEGAfm inside iPad hosts.

Host

GarageBand, Logic Pro for iPad, AUM, or another app that loads the AUv3 instrument.

Algorithm

The routing of four operators into modulators and audible carriers.

Carrier

An operator heard directly at the output.

Modulator

An operator that changes another operator's spectrum through frequency modulation.

Total Level

Operator strength. Higher values mean a stronger carrier or modulator.

Multiply

Operator frequency ratio relative to the played note.

Feedback

Operator 1 modulating itself to add harmonics or noise.

Link

A route from LFO1, LFO2, or LFO3 to a parameter.

Ghost

The translucent effective knob/fader position created by modulation.

Retrig

Restarting an LFO when a new note or arp step begins.

LFO Loop

Repeating an LFO cycle instead of stopping after one pass.

Operator Loop

Repeating one operator's ADSR cycle while a note is held.

MPE

MIDI Polyphonic Expression using separate member channels for per-note pitch and expression.

Slide

Per-note vertical expression from the full-screen onscreen keyboard or MPE CC74, routed through LFO2.