OP-1 Midi Note out issues


Pardon me, but I only have two devices that output MIDI at this time – an OP-1, and a Roland GR-55 Guitar Synth.

The following code works great on my roland guitar synth: montage-organ/montage-organ.html at main · lindseymysse/montage-organ · GitHub

But it does not work on my OP-1. I am connecting to the device as usual, with OP-1 hooked up via USB in MIDI mode, but it doesn’t seem like my OP-1 is broadcasting any MIDI out.

Is there something on the hardware side I should know about?


Does the Roland GR-55 have a USB Host port? The OP-1 is only USB-client, and requires a USB-host connection in order to interoperate. There are boxes you can get, like the Kenton USB MIDI Host, that let you connect it to other USB-client connections.

My current signal path is OP-1 in CTRL Mode => USB => LAPTOP => BROWSER

Shouldn’t the laptop act as a USB Host here?

The OP-1 Shows up in the listed devices in the browser… it just doesn’t seem to broadcast any notes

yes laptop is HOST
might be helpful to download a midi monitor app or if u have a DAW or something like that
so u can atleast test to see if the op1 is sending out midi and your laptop is receiving it

also the OP1 sends MIDI out even in regular OP1 mode too

So this is what I’ve found… my OP-1 won’t start outputting MIDI to Chrome until I switch modes from Drum to Synth, or vice versa. I have to switch modes to get the browser to pick it up, though. Which tells me it’s something to do with my software and the OP-1.

Has anyone experienced a similar quirk like this?