When nothing plays, find out why.

Test a connection

Pick an output and MIDI Noodle plays a test note straight to it. Don't know which channel your synth listens on? It plays each channel in turn; click I heard it and it names that channel for you.

Test an input instead and it shows what arrives as you play, whether that port is in the patch or not.

A checklist, most likely first

If the test stays silent, you get the usual causes in order: the device is off or offline, the DIN cable is in the wrong way round, the synth listens on another channel, MIDI Thru or Local Control is set wrong, or the device needs its USB MIDI mode. Tick them off as you go.

Stuck notes and runaway clocks

Fix stuck notes / runaway clock, next to Panic in the menu bar, asks you to stop playing for a few seconds and listens for inputs that keep sending. Then it lists what it finds in the live scene: two clocks into one device, doubled routes, MIDI loops. Tick the fixes you want; they apply as one undo step.

Panic sends All Notes Off and a reset to every output, for when something is droning right now.

See what's arriving

A light at the bottom of the devices panel flashes whenever any input sends, with the newest message beside it. Click it for the MIDI Input Log: the last 500 messages from every input port, with time, port, channel and message. Clock and active sensing are left out so the real messages don't scroll away.