A direct box (DI box) may not be the most exciting piece of gear to have to bring to your gig. But it can be a crucial component, especially when the mixing board is just a few feet further than your guitar cable reaches. To the inexperienced player, it may just seem like a cable extender sitting near your feet. There’s so much more to it, of course. Some offer a boost in volume, which is crucial for getting a workable sound. How many times have you encountered an acoustic guitar (or piano) that has too low of an output signal? Cranking the level on the mixer channel gives you too much hiss and never seems to work. At its best, a direct box takes an unbalanced, high-impedance signal and converts it to a balanced, low-impedance signal and faithfully delivers it to the mixer and out to the speakers. Some DI boxes, especially ones designed for acoustic guitar, add tone knobs, tuners and boost switches.
Mackie finally entered the direct box market with their new MDB line, part of their new Audio Tools series which debuted at Winter NAMM 2018. Four models are part of the initial launch: The MDB-1A, the MDB-1P, the MDB-2P and the MDP-USB. Other units in this category include their MTEST-1 cable tester and M48 Phantom Power Supply. We received the 1A, 2P and USB for our evaluation.
Mackie is known for their affordable, quality, road-tested and rugged live sound mixers, speakers and sub woofers. Their 1604 mixing board and SRM 450 speakers are ubiquitous in club and band setups around the world since their introduction in the ‘90s. Mackie customers are a loyal, dedicated group who trust and respect the brand name. You would think the company would have made DI boxes years ago.
The MDB-1A, MDB-1P and MDB-2P are basic DI boxes that do their job well. They’re quiet, transparent, feel (and look) good, priced right, and get the sound signal to where it needs to go. The lettering on each unit is clear and easy to read, which is crucial for quick setup time on a show.
There’s not much more to add, and that’s a good thing! But there are a few spec differences, which we’ll discuss. The 1A is a single channel active box with ¼” out and ¼” thru and XLR out. Plugging a Gibson J100 with LR Baggs Anthem pickup into the box gave the guitar the natural sound I’m used to hearing from the Anthem with a lot of headroom to spare. The 2P is a stereo passive unit featuring 2 XLR outs and Left and Right 1/4” inputs and thru. This unit will work for a guitar too, and is perfect for a keyboard L/R setup, which can be sent either to two channels on a board or summed to mono output when channels are at a premium on a board. Or you can use this DI as two separate inputs.
The MDB-USB has a completely different application from the other boxes. It’s designed for connecting your laptop computer to the mixer. It has a USB input connector, right/left XLR output, a mono switch, ground lift, a volume level, plus a headphone jack for monitoring. It’s perfect for DJ’s of course, but has applications for songwriters and strummers who use backing tracks from a computer in their performance. I found it to be a nice addition to my arsenal for sound engineering gigs. Often times I’m caught with someone who needs to connect a laptop to the board and I find myself scrambling to find the 1/8” to 1’4” or XLR adapter and hoping it works and stays connected. The MDB-USB is a simple plug and play box, powered by the computer. Setup is easy, with no drivers needed. You will need your own USB cable (male to Type B male). Once connected, the computer identifies the DI in your preferences section and then you’re set. From there, it’s all about levels! In a live setup, you’ve got three gain stages in the chain- the computer output, the MDB-USB level and your mixer controls. Once you dial in your sound, the unit does the work. With a good set of quality headphones, playback monitoring was not an issue in a noisy bar. The MDB-USB also came in handy in the recording studio when I was looking for a quick connection to listen to tracks from the guitarist’s computer. The interface is 96K 24 bit hi-rez and there’s no distortion in the playback. I could also see applications for this in a home stereo setup if you have an older stereo preamp that doesn’t have modern connection options.
The Mackie MDB series is a long-awaited and affordable entry into the DI and accessories market, with the MDB-USB getting special credit for addressing the needs of those who use a computer for live music.