In this age of USB controller keyboards and so many excellent plug-in virtual instruments, some users may never feel the need to go near a MIDI cable, but those with hardware synths or non-USB MIDI controllers still need those five-pin DIN ports. There are rather fewer manufacturers building MIDI interfaces than once there were, but ESI provide cost-effective solutions for those needing multiple MIDI ins and outs. Their M8U eX is a USB 3.1 multi-port MIDI interface. It offers 16 MIDI ports, though if that isn't enough, you can hook up multiple interfaces to the same computer courtesy of a DIP switch on the bottom of the unit which sets the device ID. If you don't need so many ports, they also offer the smaller M4U eX — this comes with eight ports but in other respects has the same feature set as its larger sibling.
Eight of the M8U eX's ports are on the front panel and eight more are on the rear of its bronze-coloured desktop case, the overall measurements being 32.5 x 14.5 x 4.5cm. Although it's a USB 3 device, the M8U eX also works fine with USB 2. It also incorporates some novel features that you don't find in competing products. Perhaps the most radical of these is that any port can be set to act either as an input or an output. Thus, you can merge multiple inputs or use only a single input but have 15 outputs. ESI's MIDI auto‑detection technology automatically recognises when a MIDI input is connected and sets the port to input status, denoted by the associated LED changing to green. This flashes gently when data is being received. Ports functioning as MIDI outs show red LEDs to denote their MIDI out status. Though the interface can be bus powered, it comes with a 5V power supply that not only takes over powering duties when used in stand-alone mode but also powers a built-in, three-port USB hub — this means hard drives, USB keyboards or dongles to be connected directly to the back of the unit, which should reduce the demands made of a laptop's USB ports!
Despite all these features, the M8U eX is a class-compliant device that works with Windows (7, 8.1 and 10) and Mac OS systems (both 32-bit and 64-bit) without the need for drivers. When not connected to a computer the M8U eX also works as a standalone thru or merge box, with a front panel push-button selecting from three preset configurations. Here you can set it to merge multiple MIDI signals to, for example, feed a single MIDI out port; use it as a MIDI splitter to send the same signal to multiple MIDI out ports; or use it as a thru box. As you step through the modes, the panel LEDs change colour to show you which ports are configured as inputs and which as outputs.
I tested the M8U eX with Logic Pro and, as advertised, it recognised my MIDI keyboard input and its available output ports showed up, correctly named, in Logic. I connected my old faithful Roland JV‑2080 to Port 8, selected it in Logic and off we went. I found the three USB ports on the rear panel to be particularly useful for hanging dongles and memory sticks without having to crawl around the back of my Mac Pro, and though I have no immediate need for the stand-alone functions, those modes are very thoughtful additions to what is already a very flexible MIDI interface — and one that puts in a solid performance to boot.