Check MIDI control-change numbers before a loop

You move a knob to start a filter change, but the loop responds to the wrong control. Or a pedal triggers a function you did not assign. Check the MIDI messages before performing so you know what each control actually sends.

The MIDI Test shows incoming messages from your keyboard or controller in a browser. Use it to check the control-change number, channel, and value before you map controls in your loop software. MIDI Test does not work in Safari, so use another supported browser if you are on a Mac.

Check the control-change numbers

1. Open the MIDI Test on the computer you will use for the performance. Connect your MIDI keyboard or controller, then allow MIDI access if the browser asks.
2. Find the controller in the test's MIDI input list, if a list is shown, and select it. If you are not sure which device is which, disconnect the controller, check the list, then reconnect it.
3. Move one knob or slider slowly from one end of its range to the other. Watch the message list for a control-change message, often shown as CC or Control Change, and note its number, channel, and changing value.
4. Repeat with each control you plan to use. Press and release buttons and pedals separately, since a switch can send a different message from a knob or slider.
5. Write down the message you expect for each performance action, such as “filter knob, CC 74, channel 1.” Then open your loop software and check that its mapping uses the same control and channel.

Move controls one at a time while testing. If you turn several knobs together, their messages can appear mixed together and make it harder to tell which control sent which number. Also test controls at the positions you will use during the performance, not only at their endpoints.

What the result means

The expected control-change number appears

The controller is sending the number you wanted. If the loop still responds to the wrong action, check the mapping in your loop software. Confirm that it listens to the same MIDI input and channel, and that the control-change number is assigned to the intended function.

A different control-change number appears

The control is working, but it sends a different number from the one your loop expects. Some hardware lets you assign a new number in its own setup or configuration utility. Otherwise, change the mapping in the loop software to match the number the controller sends.

The number is right, but the channel is different

MIDI messages include a channel as well as a control number. A loop may ignore a matching control-change message if it listens on another channel. Match the receiving channel to the controller, or set both to a channel you will use consistently.

The control sends notes instead of a control change

A button or pedal may send a note-on and note-off message rather than a control-change message. That is not automatically a fault, but your loop must be able to map that kind of message. Check its MIDI learn or input assignment options before changing hardware settings.

No message appears, or the value stops changing

The browser may not be receiving input from that device, or the control may not be sending the message type you expect. Check the selected input and browser access first. If other controls work but this one never sends a message, check the controller's setup or test it with another compatible computer.

How to fix a mismatched control

1. Select the correct MIDI input. If more than one device is connected, confirm that the test and loop software are listening to the same keyboard or controller. A controller can appear under a different name when connected through an interface.
2. Allow MIDI access in the browser. If access was blocked, open the site controls beside the address bar and review the site's permissions. If the browser offers a MIDI permission there, allow it, then reload the test. Permission labels vary by browser.
3. Check the controller's assignment. If its setup utility supports remapping, assign the intended control-change number and channel. Save or transmit the change to the controller if its instructions require it, then test the control again.
4. Update the loop mapping. Use the software's MIDI learn feature, if available, and move only the control you want to assign. Otherwise, enter the control-change number and channel you recorded in the test. Check that the assignment is saved in the project or performance setup.
5. Reconnect the controller. Try another USB port and a cable that supports data, not charging only. If you use a MIDI interface, check both its connection to the computer and the cable from the controller.
6. Restart and retest. Close the browser and loop software, reconnect the controller, then reopen them. Test the control in the browser before checking the loop again.

On Windows 11, check whether a USB device appears under Settings › Bluetooth & devices › Devices. On macOS, open Applications › Utilities › Audio MIDI Setup, then choose Window › Show MIDI Studio to inspect connected MIDI devices. These views can help confirm that the computer sees the hardware, but the browser test is what confirms the messages reaching the page.

Check the value range before performing

A control-change number identifies the kind of control, while its value shows the position or state being sent. Standard MIDI control-change values range from 0 to 127. A knob might send a gradual series of values as you turn it. A button or pedal might switch between low and high values instead.

Some familiar assignments include CC 1 for modulation, CC 7 for channel volume, CC 10 for pan, and CC 11 for expression. Treat these as common conventions, not a guarantee: controllers and performance software can use different assignments. CC 64 is commonly used for sustain, but check the actual values your pedal sends rather than assuming its behavior.

For a loop-based performance, test the whole movement you intend to make. A knob that sends the right number but only changes across a small part of its value range may not produce the effect you expect. If the test shows the correct number and a changing value, but the loop does not react, the remaining problem is likely in the software mapping, channel filter, or selected MIDI input.

If the controller sends no messages after you try another cable, input, and compatible browser, test it on another computer before relying on it onstage. For a related check, see how to recheck MIDI control-change numbers after they change.