Steinberg's Midex 8 USB MIDI interface ($499) is an 8-In/8-Out device featuring Linear Time Base (LTB) technology for greatly improved MIDI timing accuracy. If you download the latest driver software from Steinberg's Web site, you'll be able to stack as many as eight Midex 8 units to get a whopping 1,024 MIDI channels of LTB accuracy.
Although you can use the Steinberg Midex 8 with most MIDI software, you need Steinberg's Cubase VST/32 5.0 to take advantage of LTB. Also, the Midex 8 doesn't like to share its USB port with other variable-bandwidth USB devices. Specifically, if your computer has a single USB port — as most laptops do — and you intend to use the port for digital audio I/O, you probably won't be able to use the Steinberg Midex 8.
For this review, I tested the Steinberg Midex 8 on a Pentium III/700 MHz laptop with a single built-in USB port. I also used a Macintosh G3/300 MHz with a PCI card offering two USB ports. On the PC, I used Midex version 1.1 drivers with Cubase VST/32 5.0 r6 and on the Mac, version 1.0 with Cubase VST/32 5.0 r2. In both cases, I tested the unit with and without a four-port USB hub. With the hub, the Steinberg Midex 8 required external power; otherwise, it did not. In both cases, I was unable to get USB audio to work on the same port.
The Steinberg Midex 8 ships with a brief manual and a cross-platform CD for installing the MIDI driver software on the PC and Mac. It supports Windows 98SE, ME, and 2000, as well as Mac OS 8.6 or higher. Open Music System (OMS) is required on the Mac and is included on the installation CD. No external power supply is provided, and in many cases, USB power is sufficient. When external power is needed, the Midex 8 accepts power from any wall-wart power supply that provides a minimum of 500 mA at between 6 and 12 VAC or VDC (any polarity).
In a perfect world, hooking up the Steinberg Midex 8 and installing the drivers should be a piece of cake, but for several reasons, it turned out to be a bit of a hassle. On the PC, the Add New Hardware wizard that pops up when you connect the Midex 8 to the computer couldn't find all of the driver software on the CD. Therefore, I wound up with a partial installation and had to go through the usual Windows song-and-dance of trying to determine what was installed where so I could throw it away and start over. After several phone calls to Steinberg tech support, I eventually had to install everything manually.
The driver software for the Mac is missing from the CD altogether, but once you know that, it's easy to find and download it from the Steinberg Web site. On the other hand, the necessary OMS USB drivers are on the CD, but not on the Web site. Fortunately, those unnecessary bumps in the road, while annoying, are not fatal.
LTB provides a solution to the age-old MIDI-bandwidth problem that afflicts multiport MIDI interfaces. Because it takes almost a millisecond to transmit a typical three-byte MIDI message, even a single channel of MIDI data can get clogged by a MIDI stream containing lots of MIDI Note and Control Change messages. With a typical multichannel, multiport interface, all the MIDI data has to get into the same cue, and the problem magnifies quickly. The result is noticeable flamming, and it is especially a problem when combining MIDI tracks with software plug-in instruments, which do not use MIDI yet feature sample-accurate synchronization with each other as well as with audio tracks. Although nothing short of repealing the laws of physics can solve the problem for individual MIDI ports, LTB does keep the problem from compounding over many MIDI ports by managing them in parallel.
The Steinberg Midex 8 contains built-in memory and software for storing and sequencing time-stamped MIDI messages. Cubase VST/32 adds time stamps to the standard MIDI messages and sends them to the Midex 8 ahead of time. The Midex 8 lines up the MIDI messages by port and transmits to all ports at once as needed. That eliminates the multiport cue of MIDI data waiting to get down the pipe.
Is It for You?
If you are a Cubase VST/32 user with a free USB port (and you don't mind using OMS on the Mac), the Midex 8 is a good choice as a MIDI interface. If you regularly use three or fewer MIDI devices and rely primarily on software plug-ins, the 1-In/3-Out Midex 3 ($149) is a real bargain. Although the Midex 8 lacks advanced synchronization features (SMPTE, ADAT Sync, and word clock, for example), it's still worth serious consideration if you can take advantage of LTB.