MIDI Keyboard/Synthesizer Tester

This tool supports any MIDI keyboard, synthesizer, or controller that can connect to your computer via USB or a MIDI interface. It uses the Web MIDI API, which is supported in Chrome, Edge, and Opera browsers. Common devices like Yamaha, Roland, Korg, M-Audio, and Novation keyboards work seamlessly.

Make sure your MIDI device is properly connected via USB or MIDI interface before opening this tool. Click the "Refresh Devices" button after connecting. Also ensure you're using a compatible browser (Chrome, Edge, or Opera) as Firefox and Safari don't fully support the Web MIDI API. Check that your device drivers are installed correctly.

The virtual keyboard adapts to your selected keyboard size or automatically adjusts in Auto mode. You can select from 25 to 88-key layouts matching common MIDI keyboard sizes. In Auto mode, the keyboard expands dynamically as you play notes outside the current range. Keys highlight in real-time when pressed - white keys turn blue and black keys change color. This visual feedback helps verify that your MIDI keyboard is sending signals correctly.

The keyboard size selector lets you match the virtual keyboard to your physical device. Choose from 25, 32, 37, 49, 61, 76, or 88 keys, or use Auto mode for adaptive sizing. Manual sizes help visualize exactly what your keyboard should show, while Auto mode automatically expands the range as you play notes. If you play a note outside the selected range, you'll see a warning suggesting to use a larger size or switch to Auto mode.

The tool offers 10 different synthesizer types. Basic waveforms include: Sine (pure tone), Square (hollow, clarinet-like), Sawtooth (bright, brassy), and Triangle (soft, mellow). Instrument timbres simulate real instruments: Piano (rich harmonics), Organ (strong odd harmonics), Brass (bright with overtones), Strings (saw-like with full harmonics), Flute (pure with subtle overtones), and Bass (deep fundamental tone). These help you test your MIDI keyboard with various realistic sounds.

MIDI latency can occur due to several factors: USB connection quality, computer processing power, browser audio buffer size, or the MIDI device itself. Try closing other applications, using a direct USB connection instead of a hub, or checking your audio driver settings. Modern systems typically have latency under 10-20ms which is acceptable for testing.

Velocity measures how hard you press a key, ranging from 0 to 127. Higher velocity values indicate harder key presses and typically produce louder sounds. The velocity bar in the Recent Notes table visualizes this intensity. Testing velocity helps ensure your keyboard's touch sensitivity is working correctly and calibrated properly.

Play each key on your MIDI keyboard and watch the virtual keyboard display. Each key you press should highlight on the virtual keyboard and appear in the Recent Notes log. If a key doesn't appear, it may have a hardware issue. The Recent Notes log keeps track of the last 20 notes played, making it easy to verify all keys are functioning.

MIDI channels (1-16) allow multiple instruments to communicate over a single MIDI connection. Most keyboards send on channel 1 by default, but some can be configured to use different channels. The channel information in the Recent Notes log helps verify your device is sending on the correct channel and is useful for troubleshooting multi-device setups.

This tool is designed for testing and diagnostics only. It displays real-time MIDI input and generates sound for verification purposes but doesn't include recording or saving functionality. For MIDI recording, you'll need a Digital Audio Workstation (DAW) like Ableton, FL Studio, GarageBand, or Reaper.

Web browsers require explicit user permission to access MIDI devices for security and privacy reasons. This is similar to how websites request permission for camera or microphone access. The permission is needed to establish communication between your browser and MIDI hardware. This tool only reads MIDI input data and doesn't send any data to external servers.

Stuck notes can occur when a "Note Off" message isn't received properly. Try pressing and releasing the stuck key again, or mute the tool using the Mute button. Refresh the page to reset all active notes. If the issue persists, it may indicate a problem with your MIDI device's key mechanism or connection. Check your USB cable and ensure the device firmware is up to date.

Yes! Any MIDI input device will work, including pad controllers, drum machines, wind controllers, and guitar MIDI controllers. The virtual keyboard display is optimized for keyboard-style instruments, but the Recent Notes log will show all MIDI note messages regardless of the input device type. This makes it useful for testing any MIDI controller.