MIDI CC values missing after changing sustain polarity

You changed the sustain pedal polarity, and now the MIDI CC values you expected are missing. The pedal might be sending the opposite state, the keyboard may be using a different controller number, or the receiving app may not be showing the messages you expect.

First check what the keyboard actually sends, outside your music software. A browser-based MIDI test can show incoming messages and help separate a pedal or keyboard setting from an app routing problem.

Check the pedal messages

1. Open the MIDI Test in a browser that supports Web MIDI. It does not work in Safari.
2. Connect the keyboard or MIDI controller, then allow the browser to access MIDI devices if it asks. If the device is not listed, reconnect it and reload the test.
3. Press a few keys and confirm that the test receives key messages. This checks that the device is connected before you troubleshoot the pedal.
4. With the pedal released, note any controller messages. Press the pedal once, hold it briefly, then release it. Look for a control change message and note its controller number and value at each stage.
5. Repeat the press and release test after changing the polarity back. Keep the pedal connected while you compare the two results, if your keyboard permits polarity changes while connected.

A sustain pedal usually sends a switch-like control change, not a stream of gradually changing values. The common sustain controller is CC64. Its values commonly indicate off below 64 and on at 64 or above, but a pedal or keyboard can be configured differently. A simple pedal may send only 0 and 127.

What the result means

The pedal sends CC64, but the states are reversed

If the test shows an on value while the pedal is at rest and an off value when you press it, the polarity setting is likely reversed for that pedal. The messages are present, but their meaning is inverted. Change the polarity at the keyboard or controller, then repeat the test. Some pedals detect polarity at startup, so switch the keyboard off, set the pedal, and turn it back on.

The pedal sends a different CC number

The pedal is sending a control change, but it may be assigned to a different number than CC64. Check the keyboard's pedal assignment or MIDI control settings. If you use a programmable pedal, look for a setting that selects the controller number or pedal mode.

Keys send messages, but the pedal sends none

The MIDI connection works, but the pedal signal is not reaching the test. Check that the pedal is plugged into the sustain or damper input, not an expression or switch input with a different function. Confirm that the plug is fully seated and that the keyboard has a pedal input enabled.

The pedal messages appear in the test, but not in your music app

The pedal and keyboard are sending data. The issue is likely downstream: the app may be listening to a different MIDI device, filtering control changes, or assigning the pedal to another function. Check the app's MIDI input and controller mapping rather than changing the pedal again.

No MIDI devices or key messages appear

This is not yet a pedal diagnosis. The browser may not have access to MIDI, or the device connection may have failed. Try another USB port or cable, reconnect a Bluetooth MIDI device, and check the browser permission.

How to fix missing CC values

1. Check the pedal's connection. Use the keyboard's labeled sustain or damper socket. If the pedal has a polarity switch, unplug it before changing the switch, then reconnect it and restart the keyboard.
2. Set polarity at startup. Many keyboards read a simple pedal's resting state when they power on. With the pedal connected and released, restart the keyboard. If the sustain state is still inverted, power off, change polarity, and restart again.
3. Confirm the pedal assignment. Open the keyboard's own setup or MIDI menu and check that the pedal is assigned to sustain, damper, or CC64. Menu names vary by model, so use the manual for the exact path. Do not assume a setting called polarity changes the controller number.
4. Allow MIDI access in the browser. If you denied the prompt, use the site controls beside the address bar to reopen the page's permissions and allow MIDI access, then reload the test. The wording and location depend on the browser.
5. Reconnect the device. Unplug and reconnect USB, or remove and pair the Bluetooth MIDI device again. On Windows 11, check Settings › Bluetooth & devices › Devices. On macOS, check System Settings › Bluetooth for a Bluetooth device, then reconnect it.
6. Check the receiving app. Select the same MIDI input that appeared in the test. Make sure the app accepts control change messages and that CC64 is not filtered or remapped. If the test receives the messages but the app does not, avoid changing the pedal polarity again.
7. Test with another cable or pedal. If keys work but no pedal messages arrive, try a known-working compatible pedal. A pedal with the wrong plug type or a damaged cable may fit poorly without making a reliable connection.

When the pedal or input may be faulty

If the same pedal sends no messages on a second compatible keyboard, but a different pedal works in its place, the original pedal or cable may be faulty. If two known-working pedals both fail on one keyboard input, the input socket or its configuration may be the problem. Check the keyboard's warranty before arranging repair. Do not force a plug into a socket that does not match it.

Why polarity and CC assignment are separate

Polarity describes which electrical state the keyboard interprets as pressed. It does not usually choose the MIDI controller number. A reversed polarity can make sustain stay on at rest or switch off when pressed, while an incorrect assignment can send a different CC number. Testing the actual messages helps you tell these problems apart.

Some keyboards send a sustain message only when the pedal changes state, so test both pressing and releasing it rather than expecting a value to update continuously.