midi-piano-trainer.netlify.app

Piano Trainer scores you by comparing the notes it hears through your microphone against the MIDI file you loaded, then showing the result on a Session Complete screen. You get an accuracy percentage plus counts of correct, missed, and wrong notes, and a Retry button to run the same piece again. This applies to Play Along mode — the mode where the app says you "play with the song and get scored on accuracy." Watch Mode and Hand Practice are for following along and isolating one hand, not for producing this score.

What the Session Complete screen shows

When a run ends, the screen reports:

The page also shows a Retry button to repeat the session and a Close button to dismiss the summary. In the default state shown on the page these values read 0% accuracy, 0 correct, 0 missed, 0 wrong — the empty state before any scored run.

How the score is produced

Scoring depends on two things working together: the MIDI file as the reference, and microphone note detection as the input.

1. Load a MIDI file. Use Load MIDI or drag and drop a .mid file anywhere on the page. The page states you load a MIDI file "to start practicing piano with real-time mic feedback."
2. Choose Play Along mode. This is the mode described as playing with the song and getting scored on accuracy.
3. Enable mic detection. The app "detects notes played on your piano via microphone." Use the M key or the mic control to toggle it.
4. Play the piece. The app compares detected notes to the MIDI reference as the song plays.
5. Read the Session Complete summary and decide whether to Retry.

Because detection runs through a microphone rather than a MIDI cable, what the app "hears" determines your counts. A note that sounds but isn't detected becomes a missed note; a note it hears that isn't in the reference becomes a wrong note.

Detection settings that affect your score

The page exposes several detection options, and your choice changes how forgiving the scoring is:

• Detection model: Standard (instant), Basic Pitch (~80% F1), Transkun V1 (~94% F1), Transkun V2 SOTA (~98% F1), and Kong/Bytedance (~90% F1). The F1 figures are the app's own labels — higher-F1 models are presented as more accurate at recognizing notes, which generally means fewer spurious missed/wrong counts from detection error rather than from your playing.
• Noise Cancel: None, Spectral, or DeepFilterNet3. Cleaner input helps the detector avoid counting background sound as wrong notes.
• Tune Clarity, Speed, Release, Volume: These shape how note onsets and releases are interpreted, which in turn affects whether a played note registers as correct.
• Sens (sensitivity): Shown on the completion screen at 0.50 by default, with a Ready state — a control over how readily input is accepted as a note.

If your counts look inflated with wrong notes, detection settings are a reasonable first suspect before assuming your playing was off.

Calibrating before you rely on the score

The page includes a tuning step: Calibrate Tuning asks you to "Play A4 on your piano (hold for 1 second)" and shows an A4 Waiting... state until it captures the pitch. Running this first aligns the detector with your instrument's actual tuning, which matters for an acoustic piano or any instrument that isn't at standard pitch. Skipping it can bias detection and therefore your accuracy figure.

Practical reading of your results

• High missed, low wrong: the app likely isn't hearing notes you did play — check mic placement, Noise Cancel, and detection model.
• High wrong: extra detected notes, possibly from background noise or from notes outside the reference.
• Low accuracy across the board: re-check tuning calibration and sensitivity before changing how you practice.

The Retry button repeats the same session, so you can change one detection setting or one passage at a time and compare the resulting counts directly.

Keyboard controls during a session

The page lists: Space = Play/Pause, M = Mic, S = Sheet, Esc = Stop. Playback auto-pages and the sheet music scrolls as the piece advances, so you can follow the score while the app tracks your accuracy in the background.

Piano Trainer is a browser-based piano practice tool that loads a MIDI file, listens to your acoustic or digital piano through your microphone, and scores how accurately you play the notes. To start, open the site, load a .mid file, pick a mode and hand, then grant microphone access and calibrate by holding A4 on your piano for about one second. Everything below follows the controls shown on the page itself.

Before You Begin

You need three things:

• A .mid file (MIDI, not audio). The page states plainly: "Load a MIDI file to start practicing piano with real-time mic feedback."
• A piano you can play — acoustic or digital — positioned so your microphone can hear it.
• A browser session where you can allow microphone access. The mic is required for the scored modes because detection works "via microphone."

If you don't have a file ready, the page offers a Demo button, so you can explore the interface before committing your own music.

Step-by-Step: Your First Session

1. Load your MIDI file

Click Load MIDI, or drag and drop a .mid file anywhere on the page. The header will change from "No file loaded" to showing your loaded track.

2. Choose a mode

The page gives you two modes:

Start with Watch Mode if you're learning the notes, then switch to Play Along when you want feedback.

3. Choose which hand to practice

Under Hand, select Both Hands, Right Hand, or Left Hand. The page describes this as "Practice left or right hand independently," which is useful for isolating a difficult part before playing hands together.

4. Allow microphone access

Press M or click the mic control to enable detection. Your browser will ask for permission — accept it. Without this, Play Along can't score you.

5. Calibrate tuning

Click Calibrate Tuning, then "Play A4 on your piano (hold for 1 second)." The panel shows A4 and Waiting... while it listens. When it captures the note, the calibration closes and you're ready. This step matters because detection compares the pitch it hears against the expected notes — if your piano is sharp or flat relative to the reference, you'll get false "wrong" results.

6. Play

Press Space to start playback. Notes fall toward the keyboard and the sheet music scrolls. Play along; the session tracks correct, missed, and wrong notes in real time.

7. Review your results

When the song ends, a Session Complete panel appears with your Accuracy percentage and the correct / missed / wrong counts. From there you can Retry or Close.

Keyboard Shortcuts

Tuning the Detection to Your Setup

The controls panel exposes several settings that affect how forgiving or strict detection is:

• Speed — playback rate (shown as 1.00x by default). Slow it down when learning a passage.

• Noise Cancel — options include None, Spectral, and DeepFilterNet3. If your room is noisy or your mic picks up hum, try a cancellation option.

• Detection — the note-detection model. The page lists these with their reported F1 scores:

  • Standard (instant) — fastest, no accuracy figure given.
  • Basic Pitch (~80% F1)
  • Transkun V1 (~94% F1)
  • Transkun V2 SOTA (~98% F1)
  • ⚡ Kong/Bytedance (~90% F1)

  Higher F1 generally means fewer misdetections, but the heavier models may add latency. If you're getting spurious "wrong" notes, try a higher-accuracy model; if you need instant response, stay on Standard.

• Tune Clarity (0.63), Speed (3fr), Release (8fr) — fine-tuning parameters for the detection pipeline. Adjust these only if the defaults aren't working for your piano's tone.

• Volume (80%) — playback volume of the reference track.

Common Snags

• Nothing scores. The mic isn't active. Press M and confirm browser permission. Detection only works in Play Along mode.
• Everything registers as wrong. Run Calibrate Tuning again and hold A4 steadily for the full second. Also check that the reference track's volume isn't drowning out your piano.
• Notes are detected late or early. Try a faster detection model (Standard), or lower the playback Speed so you have more time per note.
• No sound / no notes falling. Confirm the MIDI file loaded — the header should no longer read "No file loaded." Press Space to start.
• Wrong hand is highlighted. Re-check the Hand selector; it applies to the whole session.

Once calibration is done, it's worth running one short piece in Watch Mode first to confirm the notes and sheet music line up with what you're seeing, then switching to Play Along for scoring.

Piano Trainer offers five selectable note-detection models: Standard (instant), Basic Pitch (~80% F1), Transkun V1 (~94% F1), Transkun V2 SOTA (~98% F1), and Kong/Bytedance (~90% F1). The model you pick changes how accurately the app identifies the notes you play through your microphone, and higher-accuracy models generally trade speed for precision. You can switch models at any time from the detection menu, and the choice matters most when you want reliable scoring rather than instant visual feedback.

The detection models compared

The F1 figures come from the app's own labels, so treat them as relative indicators rather than guarantees. In practice, a higher F1 means fewer notes are misread as correct, missed, or wrong — which directly affects the "correct / missed / wrong" counters shown at the end of a session.

How to choose a detection model

• If you want immediate visual feedback while playing, start with Standard (instant). It responds fastest, which helps when you're sight-reading or just watching notes fall.
• If your session scores look noisy or unfair, move up to Transkun V1 or V2. The jump from ~80% to ~94–98% F1 is the difference between frequent misreads and mostly clean scoring.
• If your machine struggles with the heavier models, drop back to Basic Pitch or Kong/Bytedance to keep playback smooth.
• If you're practicing a piece with fast passages, higher-accuracy models reduce the chance that quick notes are missed entirely.

There's no single "best" model — it depends on whether you prioritize latency or scoring fidelity in that session.

Settings that affect detection

Detection accuracy isn't only about the model. Several controls in the interface shape what the microphone picks up:

• Noise Cancel — options include None, Spectral, and DeepFilterNet3. Enabling noise cancellation helps isolate piano notes from room noise, which can improve detection in less-than-ideal environments.
• Tune Clarity — shown at 0.63 by default. This governs how strictly the detector interprets pitch clarity; adjusting it can help if your piano's tone is muddy or heavily reverberant.
• Speed (3fr) and Release (8fr) — frame-based timing controls that influence how note onsets and endings are tracked.
• Sens (0.50) — the sensitivity threshold for registering a note.

If detection feels unreliable, adjusting these alongside the model is often more effective than changing the model alone.

Calibrating before you rely on detection

The app includes a tuning calibration step: play A4 on your piano and hold it for about one second. This aligns the detector with your instrument's actual pitch, which matters because an out-of-tune piano will cause even a high-accuracy model to misread notes. Calibrate first, then choose your model.

Practical takeaway

Start with Standard (instant) to get playing, then switch to Transkun V2 SOTA when you care about accurate scoring. Use Noise Cancel and Tune Clarity to clean up the input before blaming the model, and calibrate tuning so the detector hears your piano correctly. The model menu is the main lever, but the surrounding settings determine how well any model performs in your room.

Piano Trainer is a free browser-based practice tool that turns any MIDI file into an interactive piano lesson. You load a .mid file, and the app listens through your microphone to detect the notes you play on a real piano or keyboard, scoring your accuracy in real time. It's aimed at pianists who want structured practice with immediate feedback, without installing desktop software or connecting a MIDI cable.

How it works

The core loop is simple: the app plays back a MIDI file as falling notes and scrolling sheet music, while your microphone captures what you actually play. It compares the two and tracks three outcomes — correct, missed, and wrong notes.

This means you need two things to get value from it:

• A MIDI file of the piece you want to practice
• A working microphone positioned to pick up your acoustic or digital piano

Practice modes

The app offers three modes, each suited to a different stage of learning:

Hand Practice can be set to Both Hands, Right Hand, or Left Hand, which is useful when one hand is lagging behind.

Note detection options

Piano Trainer offers several detection engines, and the tradeoff is speed versus accuracy:

• Standard (instant) — fastest, lowest accuracy
• Basic Pitch — roughly 80% F1
• Kong/Bytedance — roughly 90% F1
• Transkun V1 — roughly 94% F1
• Transkun V2 SOTA — roughly 98% F1, the most accurate

If you're just starting out and want instant feedback, Standard is fine. If you're polishing a piece and want reliable scoring, the Transkun options are worth the extra processing time. You can also adjust Noise Cancel (None, Spectral, or DeepFilterNet3) if your room has background noise.

Getting started

1. Load a MIDI file — click "Load MIDI File" or drag and drop a .mid file anywhere on the page.
2. Calibrate tuning — play A4 on your piano and hold it for one second so the app matches your instrument's pitch.
3. Pick a mode — start with Watch Mode to learn the piece, then switch to Play Along.
4. Adjust settings — set speed (e.g., 1.00x), hand selection, and detection engine as needed.
5. Play — the app scores you live and shows a session summary with accuracy percentage and note counts when you finish.

Keyboard shortcuts speed things up: Space for play/pause, M to toggle the mic, S for sheet music, and Esc to stop.

What to watch out for

• Microphone quality matters. A weak or distant mic will cause missed notes that aren't your fault. Get the mic close to the piano.
• Detection engine choice affects your score. If you're getting suspiciously low accuracy, try a higher-accuracy engine before assuming you played wrong.
• Tune Clarity, Speed, and Release settings (shown as values like 0.63, 3fr, 8fr) fine-tune how notes are detected — worth adjusting if detection feels too strict or too loose.
• No file, no practice. The app does nothing until you load a MIDI file, so have your repertoire ready as .mid files.

The site includes a demo, so you can try the interface before committing your own files. Everything runs in the browser — no account or download required based on the page.