How to check velocity sensitivity on MIDI keys

Your MIDI keyboard plays every note at nearly the same volume, even when you vary how hard you press. Or one key seems much louder than the others. A browser test can show whether the keyboard sends different velocity values for soft and firm presses.

The MIDI Test receives key presses and displays MIDI messages, including velocity. It can help you separate a keyboard response issue from a sound or instrument setting.

Test velocity on your MIDI keys

1. Open the MIDI Test in a browser that supports MIDI. It does not work in Safari.
2. Connect your MIDI keyboard by USB, or connect its MIDI interface. Turn the keyboard on and wait for the browser to request access to MIDI devices. Allow access if prompted.
3. Press a single key gently, then press it firmly. Watch the test for the key and its velocity value or message.
4. Repeat the same pair of presses on several keys, including one near each end of the keyboard. Keep the way you press as similar as you can.
5. If your keyboard has a velocity curve or sensitivity setting, change it on the keyboard or in its control software, then repeat the presses and compare the values.

Velocity values are usually on a scale from 1 to 127. A higher number represents a faster key press as interpreted by the keyboard. The test reads what the keyboard sends, not the physical force of your finger.

What the result means

Firm presses produce higher values than soft presses

The keyboard is detecting different playing strengths and sending different velocities. If the sound still seems equally loud, check the instrument, app, or sound module receiving the MIDI. It may ignore velocity, use a narrow volume range, or apply a curve that makes the difference hard to hear.

Values change, but the range is narrow

The keyboard is responding, but its sensitivity curve may be set to a mode that compresses the range. A velocity curve maps your press to the MIDI value sent. Try another curve or sensitivity level using the keyboard's controls or its own configuration software.

Values jump around between similar presses

Small differences are normal because finger speed is hard to repeat exactly. Look for a pattern across several tries. If one key repeatedly sends much lower or less consistent values than nearby keys, investigate that key separately.

Every press sends the same value, or no key appears

If soft and firm presses always send the same velocity, check the keyboard's settings and manual for a fixed-velocity mode. If no keys appear, the browser may not have MIDI access, the keyboard may not be connected, or the browser may not support the feature.

How to fix uneven or missing velocity

1. Check the browser permission. If you dismissed the MIDI access prompt, use the site controls beside the address bar to review permissions, then reload the test. Allow MIDI access if your browser offers that permission.
2. Try a supported browser. MIDI Test does not work in Safari. Open the page in a browser with Web MIDI support, then reconnect the keyboard and grant access.
3. Reconnect the keyboard. Unplug and reconnect a USB keyboard, try a different USB port, or check that a wireless connection is active. If it uses a separate MIDI interface, check both connections.
4. Turn off fixed velocity. Look on the keyboard for a fixed-velocity, touch, or velocity setting. The wording and controls vary by model, so use its manual if the setting is not obvious.
5. Try a different velocity curve. Choose a more responsive curve if gentle presses barely register, or a firmer curve if the values rise too quickly. Retest after each change so you know which setting helped.
6. Check the key in another setup. If only one key behaves oddly, test it with a different MIDI app or device if available. If the same key remains inconsistent, the keyboard may need service.

Windows 11 and macOS do not have a general operating system setting that makes every MIDI keyboard more velocity-sensitive. The relevant control is usually on the instrument or in software supplied for that specific model. The browser permission controls whether the page can receive MIDI input, not how strongly the keys respond.

When the keyboard may need repair

Suspect a hardware fault if one key repeatedly sends no note or a much lower velocity than its neighbors, even after checking the keyboard's settings and testing another connection. A browser test cannot inspect the key mechanism or measure the force needed to press it. If the keyboard is under warranty, contact the seller or manufacturer before opening it. Otherwise, ask a repair shop whether cleaning or replacing the key sensor is practical.

Velocity is not the same as loudness

MIDI velocity is a number sent with a note event, not a direct measurement of finger force or sound level. A sound instrument decides what that number does. It might change volume, brightness, or the sample played, and its response can vary by instrument. A keyboard can send a wide range of values while a particular sound still seems almost unchanged.

For a fair check, compare several presses on the same key and inspect the values, rather than judging by the sound alone.