CME U6MIDI Pro vs Roland UM-ONE Mk2

The CME U6MIDI Pro is what you reach for once one MIDI cable stops being enough. It packs 3 in / 3 out of 5-pin routing behind a single USB-C port, built as a standalone router rather than a plain pass-through interface.

Split, thru, merge and filtering are configured through CME's free UxMIDI Tools software for Mac and Windows, and the box passes MPE, sysex, MIDI timecode and clock alongside ordinary notes and controllers, so it holds up behind synths and controllers that lean on those messages. A high-speed optocoupler keeps the signal clean between ports.

The catch is that the configuration lives entirely in software, so there is nothing to see or adjust on the box itself once it is set. Three ports is also a ceiling, fine for a small rig, tight the moment a fourth piece of gear shows up. It has a shorter Amazon track record than the budget pick, with under a thousand reviews so far.

The Roland UM-ONE Mk2 is the one-cable answer to a simple problem: one piece of 5-pin MIDI hardware talking to a computer. Roland has made a version of this same one-cable interface for years, and this is that idea shrunk down to 1 in / 1 out and nothing else.

FPT processing, Roland's low-latency circuitry, keeps clock timing tight enough for a drum machine or arpeggiator locked to a DAW. It runs on USB bus power with no separate adapter, works with Mac, Windows and iPad via Apple's Camera Connection Kit, and the USB and MIDI cables are built into the unit rather than sold apart.

The tradeoff is in the name: one port each way, no merge, no thru, nothing to configure because there is nothing to configure. For a single synth it is the right amount of interface. For a rig with three or four pieces of MIDI gear, it is the first cable you outgrow.