Devlog #1: my own metronome was fooling my app

Build-in-public, since I said I'd post the messy parts here.

Here's the mess. one&a listens to your pad through the phone's mic, and the metronome plays out of the phone's speaker. So the mic hears your hits and the click in one signal, and when the click lands on the same spot as a soft ghost note from your weak hand, the app can't tell them apart. The metronome gets in the way of its own measurement.

The clean fix is headphones: send the click to your ears, let the mic hear only your hands. But a cable is a hassle, and I want one&a to just work when you sit down with nothing but your phone and a pad. So the real question was whether I can keep the measurement honest with the click coming out loud, into the room.

The wall I kept hitting: if a ghost note is quieter than the click bleeding into the mic, and it sits right on the click, nothing I tried can measure it honestly. The standard onset detectors everyone reaches for did worse than useless with a speaker going.

So tonight I tested the obvious move: let the click play only on the quarter notes, and you play your sixteenths and triplets around it, leaving the ghost positions click-free.

It worked, cleanly. Same drummer, same ghost notes: with a click on every subdivision the ghost notes flatten out at the click's own level, so your softening is invisible; with the click only on the quarters, the real trajectory shows up, the quietest ghost still sitting well above the noise floor. No accuracy lost anywhere else, and no phantom hits. Chart in the comments.

So that's the call: a quarter-note click, and the screen shows you the grid you're actually playing. The part I didn't expect to like: fewer clicks is less of a crutch. You hold the sixteenths yourself between the quarters, which is closer to the whole point of pad practice. Later I'll probably let you make the click denser if you do put headphones in, but the default has to earn its keep without them.

That's also why the test build didn't ship today. I'd rather get this honest first than push a version that quietly lies to you about your left hand.

Next: an even-hands drill you can do with or without the app.