Documentation

A Musician's Guide

Everything you need to go from install to first gig. Prefer paper? Download the PDF.

What is MIDI Assistant?

MIDI Assistant is your backstage helper for Apple MainStage — a Mac app, an AUv3 plugin, and a companion iPad Remote that work together to give you superpowers MainStage doesn't have on its own:

• Complex MIDI automation — fire sequences of MIDI events with a single button press
• A real Mixer Console — a dedicated, fully customizable fader-and-matrix control surface for your whole rig
• Smart routing — route and rename MIDI between controllers without rewiring anything in MainStage
• A live performance surface — run the whole show from an iPad, in perfect sync with the Mac

The three pieces

Piece	What it's for
MIDI Assistant (Mac app)	Where you build your rig: the Mixer, the Concert Editor, MIDI Routing, and Capture/Catalog tools.
AUv3 plugin (Host FX Mode)	Loads directly into a MainStage channel strip so MIDI Assistant's processing runs alongside your instruments, sample-accurate, inside MainStage itself.
iPad Remote	The surface you actually touch on stage — four interchangeable layouts, always in sync with the Mac.

Real-world use cases

1. One-button Scene changes

The problem: changing from your verse sound to your chorus sound means hitting multiple buttons, changing patch, adjusting volume faders, and hoping you time it right.

The solution: tap a single Section button — on the Mac or the iPad Remote — and MIDI Assistant fires the whole cued sequence: program changes, fader ramps, patch swaps, all at once.

2. Tempo-synced transitions

The problem: you want a filter sweep or volume fade that takes exactly 2 bars, every time, regardless of tempo — and you don't want it to jump when it starts.

The solution: convert a fader event to a Dynamic Ramp. MIDI Assistant reads the actual current value of the parameter and ramps smoothly from there to your target, timed in Bars, Beats, or Seconds, using Linear, Exponential, Logarithmic, or S-Curve shaping. No jump, no manual retiming when the tempo changes.

3. Controller name freedom

The problem: MainStage knows your controller as "Network Session 1" or "Launch Control XL" and you can't rename it. Your mapping list becomes confusing.

The solution: MIDI Assistant creates a virtual port with any name you want and routes your controller through it via a Namespace — a logical tag like Lead Synth instead of a raw channel number. Swap the physical keyboard later, and you re-point one Namespace instead of hunting down every mapping.

Key concepts

Scenes, Sections & Master Patches

Think of a Scene as a song, and its Sections as the parts of that song (Intro, Verse, Chorus, etc.). Each Scene also carries a Master Patch — the actual MainStage or external-synth program it loads — plus its own list of MIDI events per Section.

Presets

Presets are reusable event bundles, most often used for plugin/effect settings. Unlike a Scene (a whole song), a Preset is a portable chunk you can drop into any Section.

• Store your favorite reverb settings and recall them across multiple songs
• Trigger a Preset independently, or attach it to a button's ON/OFF actions
• Right-click a Preset in the Concert Editor and choose Add to Current Section to copy its events straight into the Section you're working on

The Mixer & SubScreens

The Mixer Console is your main control deck — faders, a button matrix, and top/side utility buttons, all built dynamically from your Concert. When a rig has more depth than fits on one screen (32 Omnisphere matrix buttons, 40 organ drawbars), that complexity lives in a SubScreen — its own isolated control surface, reachable by pressing and holding (or right-clicking) a fader's name label.

Need quick access to one deeply-nested SubScreen control without leaving the main Mixer? Create a Ghost Control — a lightweight reference that mirrors the original control's value, label, and behavior automatically.

Radio Groups & Momentary buttons

Buttons default to Toggle (latching) behavior. Flip a button to Momentary for stutter effects or drum-pad style hits that only fire while held. Give several buttons the same Radio Group, and pressing one automatically turns the others off — perfect for "only one patch active at a time" selections.

Soft Takeover

Moving a scene to a new state can leave a physical (non-motorized) fader pointing at the wrong value. Soft Takeover prevents the jump: in Pickup mode the fader has to physically cross the current value before it takes control again; in Proportional mode it scales your movement so it catches up smoothly instead.

The Legato Engine

Changing scenes mid-chord shouldn't cut your sustain dead. MIDI Assistant's Legato Engine keeps the old patch sounding until you actually release those notes, then cleans up automatically — no special playing technique required.

Setting up for your first gig

What you'll need

1. MIDI Assistant installed on your Mac (macOS 13 or later)
2. MainStage, with the MIDI Assistant AUv3 plugin loaded on a channel strip (Host FX Mode) if you want sample-accurate in-host control
3. MIDI Assistant Remote on your iPad, on the same local network as your Mac
4. Your controllers (Lemur, Launch Control XL, hardware keyboards, etc.)

Quick start

1. Open MIDI Assistant on your Mac.
2. Open the MIDI Routing window and set up your virtual ports and hardware interceptions — this is where physical controllers get routed and (optionally) renamed via Namespaces.
3. Open MIDI Assistant Remote on your iPad; it connects to the Mac automatically over your local network.
4. Build your first Concert in the Concert Editor: add a Scene, rename Section 1 to something real (Intro), and set a Master Patch trigger so the right sound loads with it.
5. Switch to the Performance Hub (Mac) or the Remote's Full Stage or Mixer layout to run the show live.

The iPad Remote: four ways to look at the same show

Switch layouts from the toolbar's mode menu — no reconnecting, no lost state:

Mode	Use it when…
Compact (Lemur)	You want the smallest footprint alongside other apps.
Full (Stage)	The iPad is the show — big touch targets, big labels.
Setlist Only	You just need to pick the next song.
Mixer (LaunchCtrl)	You want the fader-grid mixer, iPad-side.

Tap a Section pill to jump straight to it. Tap the Scene name for a menu of every Scene and Section — a direct jump from anywhere to anywhere. If a Section has a duration, tap its progress bar to pause or resume the countdown.

A day in the life: Concert workflow

Before the gig

1. Build or update your Concert in the Concert Editor — Scenes, Sections, Master Patch triggers.
2. Dial in your rig's routing profile for the venue (a simple solo setup vs. a full band rig with multiple controllers).
3. Use Ad-Hoc Capture to grab a perfect soundcheck balance straight into a Section, instead of hand-typing every fader value.

During the gig

1. Launch MIDI Assistant on the Mac; open MainStage.
2. Run the show from the Performance Hub (Mac) or the iPad Remote — whichever surface you're actually standing behind.
3. Hit your Section buttons and let the Legato Engine, Dynamic Ramps, and Soft Takeover handle the details.

After the gig

1. Save any on-the-fly Ad-Hoc Presets you want to keep.
2. Review anything that felt off — a Section that ran long, a fader that jumped — and adjust.

Tips from the stage

1. Always test before the gig

Play through your setlist end to end with the actual rig connected, not just on the bench.

2. Use descriptive names

Name your Sections "Intro", "Verse 1", "Chorus" — not "Section 1", "Section 2". Your future self will thank you.

3. Start simple

Get basic routing and one Scene working before layering on Ramps, Ghost Controls, and SubScreens. Build up gradually.

4. Capture instead of retyping

If a mix sounds perfect at soundcheck, use Snapshot → Save Ad-Hoc Preset rather than hand-entering thirty CC values.

5. Lean on Dynamic Ramps for safety

A ramp always starts from the fader's real current position — it can't jump, even if the previous Section left things in an unexpected state.

Troubleshooting

Glossary

Term	Meaning
Concert	Your full setlist — every Scene, Section, and mapping for a show.
Scene	A song in your setlist.
Section	A part of a Scene (Intro, Verse, Chorus, etc.).
Master Patch	The actual MainStage/external-synth program a Scene loads.
Preset	A reusable, saved bundle of MIDI events.
Namespace	A logical tag standing in for a hardware channel, so mappings survive a gear swap.
SubScreen	An isolated control surface for a deep instrument's parameters.
Ghost Control	A lightweight reference that mirrors another control's value on the main Mixer.
Radio Group	A set of buttons where turning one on turns the others off.
Dynamic Ramp	A smooth, jump-free transition from a parameter's live value to a target.
Soft Takeover	Prevents a physical fader from causing a value jump after a scene change.
Legato Engine	Keeps a sustained chord alive across a scene change until it's released.

Need help?

Email support@rodwilsonmusic.com or visit the Support page.