MIDI Surface is a touch-driven MIDI control surface and sample instrument. It draws your controller as an on-screen grid of glowing pads, knobs and faders that light up as you play the real hardware — and, on devices with lit pads, tapping the screen sends the signal back to illuminate the hardware in return. Every pad can also fire a looping audio sample shaped by live effects.
How it works. The app connects to your controller through the browser's Web MIDI and reads a bundled profile (shipping with an AKAI LPD8 preset) that describes the grid and one or more channel banks of pads, knobs and faders. Incoming notes and CC messages light the matching control on screen; touching a control sends MIDI straight back out on the same channel the hardware speaks on, so the device's LEDs stay in sync. Each pad holds a looping sample played through a Web Audio engine, and every pad carries its own effect chain — volume, pitch, reverb and chorus. Knobs and faders are assigned to drive an effect on a chosen pad, so a dial becomes, say, the reverb on pad 3. Pads can be momentary or sticky (switch) toggles, and speak either notes or CC for controllers running in CC mode.
How you interact:
- Enable audio — tap once to unlock sound (browsers require a first tap) before you play.
- Play the grid — tap pads to trigger their samples and drag a knob or fader up and down to sweep its effect; hardware and touch stay mirrored.
- Channel banks — switch between mapping banks with the CH buttons in the header.
- REC learn — arm a trigger, then hit a pad or turn a knob on your controller to assign its note or CC automatically.
- Stop all — release every held pad and silence all audio in a single press.
- Settings — pick a controller, edit each trigger's type and note, assign or browse local samples, map knobs to pad effects, and Load or Export the whole setup as JSON.
Self-contained and offline — plug in a USB MIDI controller, or play the surface entirely by touch.