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Emagic MT4

USB MIDI Interface By Paul White
Published October 2000

Emagic MT4

Paul White tries out Emagic's compact two input, four output USB MIDI interface.

The Emagic MT4 is a compact USB MIDI interface that draws its power from a USB port rather than from a separate power supply. Compatible with both Mac and PC computers (providing they have USB interfaces), the MT4 is designed to work with the majority of music software, as it supports OMS and FreeMIDI in addition to its direct compatibility with Emagic's Logic series of sequencers. The unit comes complete with USB cable and software on CD‑ROM.

Measuring a little over six inches wide and two and a half inches front‑to‑back, the unit has two MIDI In ports and four MIDI Outs, thus providing 64 MIDI channels. Status LEDs are provided for each port, and there are two further LEDs that signify Patch or USB operation: when a compatible MIDI music program is loaded, the MT4 automatically switches to USB mode, but when it's not being controlled by the computer, it reverts to Patch mode, allowing it to be used as a stand‑alone MIDI router. The most obvious application of the patch system is to allow a master keyboard to play one or more sound modules without going via the computer. However, Patch mode operation requires that the MIDI interface be powered up, and as it receives power only via the USB interface, this means that either the computer or an active USB hub must be switched on too.

There are 32 possible routing patches that can be set up using the included Memory Manager software, and once set, the patches are retained in memory via an internal backup battery. Apparently the unit may also be programmed via Emagic's Sound Diver universal editor, though I wasn't in a position to test this. Patches may be named, and switching between patches is accomplished using MIDI program changes. As part of the setup, you must select the MIDI In port and the channel to be used for patch selection. If this is the same port as used for connecting the master keyboard, patch changes can be sent directly from the keyboard.

MIDI Timing Data

Emagic MT4

Real‑time MIDI messages are passed by the interface, so it can be used in a setup that relies on MIDI sync, but only one of its inputs is allowed to handle real‑time MIDI data at a time. To allow both would be to invite the merging of data streams each carrying MIDI timing data, which is virtually guaranteed to confuse any MIDI software. The system adopted is that the first channel to receive a MIDI Start or Continue message sets itself up as the Clock Master port. It remains in this state until a MIDI Stop is received, after which it relinquishes the status. However, the port keeps passing real‑time MIDI messages until another port receives a Start or Continue command, at which point that becomes the new Clock Master port.

<h3>In Use</h3>

I tested the MT4 using Logic Audio running on a Mac G4 computer. Unlike the same company's AMT8 (reviewed in SOS January 2000), the MT4 doesn't feature Emagic's Active MIDI Transmission (which can improve MIDI timing when used with compatible software), so its timing resolution will be limited by the resolution of the USB port to which it is connected. Even so, on my Mac G4 the MT4 seemed to behave just like any other MIDI interface as far as timing was concerned, and this should remain the case regardless of the host sequencer software.

The routing software is easy to use and installation is simple. Logic recognises the MT4 like an old friend, and all you need to do it set up Logic's Environment so the system knows which synths are plugged into which ports. Configuring the patches is also easy — it's just a matter of putting dots in a grid to connect the inputs to the outputs, after which you type in a patch name. OK, so a MIDI interface isn't the most exciting of devices, but if you have a USB computer and want an interface with more than the usual one or two output ports without shelling out for one of the rackmount big boys, the MT8 is a sensible option.


  • Includes a useful patching system.
  • Mac‑ and PC‑compatible, with both OMS and FreeMIDI support for non‑Emagic applications.


  • Requires a powered USB connection in order to run in Patch mode.


A simple mid‑market USB interface for when basic interfaces are too limiting but where an eight‑port interface would be overkill.