Field guide
From the kit to the light.
How to wire it, what each status means, and what each drum does.
Where this stands
Tested in Chrome on a Mac with a simulated audio input and a virtual MIDI port, using a synthetic drum loop. No real drum kit has been played through it yet, so the pad map and the audio estimates are starting points.
Wiring
This route is for a Pearl Mimic Pro and a Universal Audio Apollo Solo. Any interface and any kit with 5-pin or USB MIDI works the same way.
- Audio. Two 1/4-inch TRS cables from the Mimic Pro's Line Out 1 and 2, which carry the main mix, to the Apollo Solo's rear Mic/Line 1 and 2. Set both inputs to Line, and leave the front Hi-Z jack empty, because a plug there takes over input 1.
- MIDI. The Apollo Solo has no MIDI ports, and the Mimic Pro's USB slot is for installing samples. Run a 5-pin cable from the module's MIDI OUT into a USB-MIDI interface, and plug that into the computer.
- In the page. Press Connect, then Connect audio and MIDI, and allow both prompts. Choose "Universal Audio Thunderbolt" for audio. The MIDI list shows your interface's name, not the module's.
- Listening. These pages never play your input back, so keep monitoring through your interface.
Browsers
| Browser | Audio | MIDI |
|---|---|---|
| Chrome, Edge | Yes | Yes, after a permission prompt |
| Firefox | Yes | Only with a site permission add-on |
| Safari | Yes | No. Safari has no Web MIDI, so hits come from audio |
Only Chrome has been tested so far. Capture and MIDI both need a secure page, which the published pages are.
What the status means
| Ambient | Nothing is connected. The picture is idling, not responding to anything. |
|---|---|
| Permission denied | The browser or the system refused. The Connect sheet says which and how to allow it. |
| No device | The browser allowed it, and the computer shows no such input. |
| No signal | The device is open and nothing is arriving. Check the cable, the module's volume and the input gain. |
| Live | Signal is arriving. The label says whether hits come from MIDI or are estimated from audio. |
| Demo | A synthetic drum machine, not your kit. The label stays up as long as it runs. |
| Replay | A session file you loaded. Nothing in it is live. |
MIDI and audio together
MIDI names the drum, its velocity, the hi-hat pedal and cymbal chokes. Audio gives the picture its real spectrum. When both are live, MIDI decides the hits, so nothing fires twice.
With audio alone, four frequency bands estimate kick, snare, hat, tom and crash by a stated rule, and a ride is not told apart. With MIDI alone, each hit paints a stated spectrum shape rather than a measured one.
The note numbers on your module can be changed, so the map is a starting point. Open Connect, then Pad map and Learn, press Learn beside a pad and hit it.
What each drum does
| Drum | Nebula | Endless Cockpit |
|---|---|---|
| Kick | A pulse outward from the core | A surge forward and a ring of light down the road |
| Snare | Scatters the field and stirs the fluid | A flare across the land |
| Hi-hat | Sparkle in the top third, wider with the pedal open | Sparks on the road edge and stars, longer with the pedal open |
| Toms | A swell at that tom's height | A band of light in the sky at that tom's height |
| Crash | Long trails and a brief wash | Aurora and long trails |
| Ride | A fine shimmer | Stars and road edge shimmer |
| Tempo | A readout | The speed: half your BPM stands in for cadence |
| Spectrum | Color and brightness along the spiral | The ridge on the horizon |
Safety and privacy
A limiter slows any large change in brightness, and these pages measure under the WCAG limit of three flashes a second, even with hard playing. That is a measured screen, not a medical guarantee. If flashing or moving light affects you, take care, and turn on your system's reduced-motion setting, which tightens the limiter, calms the camera and removes the flash.
Audio and MIDI are analyzed in this browser and never sent anywhere. A session file holds hits, pedal moves and levels, with no audio in it.
Credits
No outside code is included. Ideas came from these projects:
- Butterchurn (MIT): Milkdrop's feedback warp, behind the road's trails.
- WebGL Fluid Simulation (MIT): one splat per impact, behind Nebula's stirred field.
- paper-cranes (BSD-3-Clause): reading each audio feature against its own recent range.
- @audio/beat: energy flux for percussive onsets.
- realtime-bpm-analyzer (Apache-2.0): tempo from live input.