Conjure · Hand vocoder
Studio vocoder, hand control
The vocoders in those videos are studio plugins running in a music app. Conjure does the hand tracking and sends the chords over MIDI: open hand plays the chord, fist cuts it, hand height picks which chord. Your voice and the vocoder run in Logic Pro or Ableton Live at full studio quality.
ConjureTracks your hand in Chrome and sends the chord as MIDI notes.
IAC DriverA built-in virtual MIDI cable on every Mac.
Logic or AbletonYour mic plus their vocoder make the sound.
1 Turn on the Mac's virtual MIDI cable
You only do this once.
- Open Audio MIDI Setup. It's in Applications → Utilities, or search for it with Spotlight (⌘ Space).
- In the menu bar choose Window → Show MIDI Studio.
- Double-click IAC Driver.
- Tick Device is online. There should be one port listed, normally called Bus 1. If the list is empty, click + to add one.
- Click Apply and close the window.
2 Point Conjure at it
- Open Conjure in Chrome or Edge. Safari can't send MIDI from web pages.
- Open Hand vocoder and press Sound: built-in until it says Sound: your vocoder app (MIDI).
- Press Connect MIDI and allow MIDI when Chrome asks.
- The button next to it should read To: IAC Driver Bus 1. Press it to cycle through other outputs.
Did you turn on the IAC Driver after opening Conjure? Reload the page so Chrome sees the new port.
3 Set up the vocoder
Pick the music app you have. Use headphones: with speakers, the mic hears the vocoder and you get feedback.
Logic Pro (Mac)
- Create a new project with one Software Instrument track.
- Click the track's Instrument slot and load EVOC 20 PolySynth, Logic's vocoder.
- At the top of the EVOC window, open the Side Chain menu and choose your microphone input (usually Input 1).
- Keep that track selected. Logic sends incoming MIDI, including the IAC Driver, to the selected instrument track.
- Sing a held note into the mic, then open your hand in front of the webcam.
For the crisp, talky sound: keep the sidechain Attack low, start Release around 8–10 ms, and use all 20 bands. Apple's guide recommends this as a starting point. Add some reverb and chorus after the EVOC for the big, wide sound.
Ableton Live (Standard or Suite)
- In Settings → Link, Tempo & MIDI, turn on Track for the input called IAC Driver (Bus 1).
- Synth track (the carrier): make a MIDI track with a bright pad or saw synth (Wavetable or Analog work well). Set MIDI From to IAC Driver, set Monitor to In, then mute the track. The vocoder still hears it.
- Voice track: make an audio track with your mic as the input and Monitor set to In. Drop Vocoder (Audio Effects) on it.
- In the Vocoder, set Carrier to External, then choose your synth track and Post FX in the menu below.
- Sing, open your hand, done.
Any other vocoder
Any vocoder or synth that listens to MIDI works the same way: iZotope VocalSynth 2, Arturia Vocoder V, TAL-Vocoder, or a hardware synth. Conjure sends ordinary MIDI notes on channel 1 to the output you pick.
4 Play
| Your hand | What Conjure sends |
|---|---|
| Open | Holds a 5-note chord (note-ons on channel 1) |
| Fist | Releases it (note-offs) |
| Hand height | Picks one of 4 chords in your key. Also CC 74, handy for a filter |
| 1–4 fingers on your other hand | Picks the chord directly |
| How wide your hand is open | Note velocity and CC 1 (mod wheel), great for vibrato or brightness |
| Key and scale menus in Conjure | Change which chords you get |
Bonus: in Conjure's settings (the gear icon), turn on Send instrument notes to MIDI. Then the air harp, air piano, laser harp, beat grid and every other instrument also play your music app. Drums go out on channel 10 with standard drum notes.
? If something's off
| Problem | Fix |
|---|---|
| Conjure says “No MIDI outputs” | Turn on the IAC Driver (step 1), then reload Conjure. |
| The music app shows no MIDI coming in | In Logic, select the instrument track. In Ableton, check the IAC input has Track on and the synth track's Monitor is In. |
| Silence even though MIDI arrives | A vocoder needs both signals at once. Check the mic input level and that you're singing while your hand is open. |
| A note keeps ringing | Press Panic in Conjure (top bar or settings). Pausing with Esc also releases everything. |
| Feedback or howling | Use headphones, or turn the speakers down. |
| Your voice feels late | Lower the audio buffer in your music app (Logic: Settings → Audio → I/O Buffer Size, try 128). |