Live Note Grading: How the App Knows If You Played the Right Key

Super Simple Piano grades every note you play in real time. Here's what's happening under the hood — and why some "Perfect!" scores feel earned and others feel mysterious.

The two grading paths

MIDI input is the easiest: each key press sends a precise note number and timestamp. The grader compares the note + timing to the score and labels it.

Microphone input runs pitch detection — the browser samples audio every few milliseconds and estimates the fundamental frequency. The grader rounds that to a MIDI note and feeds it through the same logic. It's accurate for melody work, fuzzier for dense chords.

What counts as a "Perfect!"

Each note in the song has a target time and a target pitch. We compare your input against three windows:

Wrong pitch at any timing counts as a miss.

What you see on screen

Performance mode vs Waiting mode

Performance mode runs the song end-to-end and grades as you go — best when you can stumble through. Waiting mode (the WAIT clock icon) pauses at every note until you play the right key — best for first-pass learning. See Performance vs Waiting mode for which to use today.

What the coaching report does

When the song ends, you get a modal with your overall grade plus a button that loops the measures you struggled with at 80% speed. No need to figure out what to drill — the data tells you.

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Real-time feedback with no judgement, just data. Try it now or read the full setup guide.