How to test MIDI connections with a browser sound preview

Your MIDI keyboard is connected, but you are not sure whether the computer is receiving its notes. Or the browser shows activity, but you cannot hear anything. These are two separate checks: MIDI sends note and control data, while your computer’s audio output makes sound.

Use the MIDI Test to check incoming notes, velocity, knobs, pedals, and other messages. Its sound preview helps you check audio too, so you can tell whether the problem is the connection or the sound output.

Test the MIDI connection

1. Connect your keyboard or controller to the computer. Use its USB cable, or connect it through Bluetooth if the device supports MIDI over Bluetooth. Turn the device on.
2. Open the MIDI Test in a browser that supports MIDI access. Safari does not support this test. If you are using Safari, see why browser MIDI testing does not work in Safari.
3. Allow MIDI access if the browser asks. If the test lists more than one input device, choose the keyboard or controller you want to check.
4. Press and release a few keys, one at a time. Look for the matching keys and MIDI messages in the test. Try a soft press and a firm press to compare velocity, which is how strongly a note was played.
5. Start the test’s sound preview, then press a key again. Listen for a tone through your selected speakers or headphones. If your device has knobs or pedals, move or press one and check whether the test registers its message too.

Test one control at a time at first. This makes it easier to match each physical action to what appears in the browser. MIDI data and the sound preview are checked in the browser on your device.

What the result means

Notes appear and the preview is audible

The browser receives MIDI input and can play sound through the selected output. If a music app still does not respond, check that app’s MIDI input selection and instrument settings. The test confirms that notes reach the browser, not that another app is configured to use them.

Notes appear, but you hear no preview

The MIDI connection is working. The issue is more likely the browser’s audio output, system volume, or a muted speaker. Try another output device and check the sound settings below. A MIDI message is not itself a recording or sound, so visible activity can still occur when audio is unavailable.

No notes or messages appear

The browser is not receiving input from the selected device. Check the cable, device power, browser permission, and selected input. If the keyboard works in another application but not in this test, try a supported browser and reload the page.

Some keys work, but others do not

The test is receiving at least part of the keyboard’s input. Try each problem key individually, then check whether it sends a message when pressed and when released. If the same keys fail in other software too, the issue may be with the keyboard rather than the browser.

Keys work, but knobs or pedals do not

Some controllers send different kinds of MIDI messages for keys, knobs, and pedals. Check the device manual for whether those controls send MIDI, and whether they need to be enabled or assigned before they produce messages.

How to fix it

1. Check the cable and power. Disconnect and reconnect the USB cable, turn the keyboard off and on, and try another USB port. If you are using a hub, connect directly to the computer to rule out the hub.
2. Allow MIDI access in the browser. Open the site permissions using the icon beside the address bar, allow MIDI access if that option appears, then reload the test. If you denied access earlier, change the permission there before testing again.
3. Choose the correct input. If several MIDI devices are available, select the keyboard you are pressing. Disconnect unused controllers temporarily if it is not clear which name matches your device.
4. Check the audio output. On Windows 11, open Settings › System › Sound and select the speakers or headphones you want to use. On a Mac, open System Settings › Sound › Output and choose the right device. Raise the volume and make sure the output is not muted.
5. Check the wireless connection. If the keyboard uses Bluetooth, confirm it is connected in Windows 11 under Settings › Bluetooth & devices › Devices, or on a Mac under System Settings › Bluetooth. Reconnect it if necessary, then reload the test.
6. Try a different supported browser. MIDI access is not available in Safari. If the test still receives nothing, close other software that may be using the device, reconnect the keyboard, and try again.

When the keyboard or connection may be faulty

Test the keyboard on another computer, using a cable you know works. If no notes appear there either, check the keyboard’s MIDI settings and try another port or cable if available. If the same keys or controls remain silent across devices, the keyboard may need repair. For a new or recently purchased controller, contact the seller or manufacturer before opening it.

Why MIDI activity and sound are different

MIDI carries instructions such as “play this note” or “move this control.” It does not normally carry the recorded sound of an instrument. The browser’s preview makes a simple sound in response to incoming notes, but it does not reproduce the keyboard’s built-in piano, organ, or synth sounds. If the test shows notes but the preview is silent, check audio output. If the preview works but your music app is silent, check the app’s MIDI input and instrument setup.