How to test a MIDI keyboard through a USB hub

Your MIDI keyboard is plugged into a USB hub, but your music software does not respond. The keyboard may be working while the hub, cable, browser, or a permission setting is stopping its messages.

Test the keyboard in a browser first, then compare the hub connection with a direct connection. The MIDI Test can show incoming keys, velocity, knobs, pedals, and MIDI messages without opening a music program.

Test the keyboard through the hub

1. Open the MIDI Test in Chrome or Edge on a computer. MIDI Test does not work in Safari.
2. Connect the keyboard to the hub, then connect the hub to the computer. If the keyboard needs external power, turn it on and check its power indicator.
3. If the browser asks for MIDI access, allow it. Wait for the page to show the keyboard or incoming MIDI activity. If it does not appear, reload the page once with the keyboard already connected.
4. Press one key at a time, then try a few keys together. Move a pitch bend wheel or knob, if your keyboard has one, and press the sustain pedal if it is connected.
5. Watch for the key, control, or MIDI message to appear in the test. Repeat the same actions after disconnecting the hub and connecting the keyboard directly to the computer.

Change only one thing between checks. For example, keep the same keyboard and cable, and compare the hub with a direct USB port. That helps identify whether the hub is part of the problem.

What the result means

Notes and controls appear through the hub

The keyboard and hub are passing MIDI data to the browser. If your music software still does not respond, check that it has selected this keyboard as its MIDI input. Some programs also need you to enable the keyboard for the current track or instrument.

Notes appear, but a knob or pedal does not

The hub is passing at least some MIDI data, but the control may be disconnected, assigned differently, or not sending messages. Check the pedal and control connections at the keyboard, then test each control separately. A pedal that works in one jack may not work in another if the keyboard has different pedal inputs.

The keyboard works directly but not through the hub

The keyboard itself can send MIDI, so focus on the hub, its connection to the computer, or available power. A bus-powered hub draws power from the computer and may not supply enough for several connected devices. A powered hub has its own power adapter, though the adapter and hub still need to be working properly.

Nothing appears through either connection

The issue may be the keyboard, USB cable, browser support, or access permission rather than the hub. Try another data-capable cable and USB port, then check that the browser has access to MIDI devices. A cable that charges a device is not necessarily able to transfer data.

How to fix a MIDI keyboard the browser cannot see

1. Reconnect the keyboard and hub. Turn the keyboard off, unplug it from the hub, and reconnect it securely. Then reconnect the hub to the computer and turn the keyboard on.
2. Try another USB cable and port. Use a cable known to carry data, not just power. Connect the hub to a different computer port, and avoid daisy-chaining one hub through another while troubleshooting.
3. Reduce the hub's load. Disconnect other devices from the hub and test the keyboard alone. If it works alone, reconnect the other devices one by one. For a keyboard that needs more power, try a powered hub with its correct adapter.
4. Check whether the computer sees the keyboard. In Windows 11, open Settings › Bluetooth & devices › Devices and look for the connected device. On macOS, open System Settings › General › About › System Report, then select USB in the report. If it is missing there too, the browser cannot receive its MIDI data.
5. Check browser access and support. Use Chrome or Edge on a computer, and allow MIDI access if the browser asks. If access was blocked, open the browser's site permissions for TooLab, allow MIDI or device access if that option appears, and reload the page. A work or school browser policy may block this feature.
6. Restart the keyboard and computer. Restarting can clear a stuck USB connection. After the computer starts, connect the keyboard and hub before opening the test page.
7. Check for a keyboard driver or setup requirement. Some keyboards work as standard USB MIDI devices, while others need manufacturer software or a driver. Check the keyboard's manual if the computer sees it but neither the browser nor your music program receives messages.

When the hub or keyboard may be faulty

If the keyboard sends notes when connected directly but fails through the same hub on more than one computer, the hub or its power supply is a likely cause. If other USB data devices also fail through that hub, replace or repair the hub rather than changing keyboard settings.

If the keyboard fails directly with a known-good data cable and does not appear in the computer's USB device list, test it on another computer. If it still cannot connect, check its power and USB port. A damaged port or keyboard may need warranty service or repair.

Why a hub can affect MIDI

MIDI notes are small messages, so a working USB hub usually passes them without trouble. The more common issue is that the keyboard loses its USB connection or does not get enough power, especially when the hub also supplies power to other devices. A browser test checks whether MIDI messages reach the browser, but it does not confirm that every music program is configured to use them.

The test reads MIDI input in your browser. It does not play the keyboard's built-in sounds or prove that an instrument in your music software is configured correctly.