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Review: Dangerous Music D-Box

May 1, 2008 12:00 PM, By Mike Levine

           

COMBINING ANALOG SUMMING, MONITOR CONTROL, AND SUPERIOR SOUND QUALITY

BONUS MATERIAL
Check the specs: Download a PDF of the Dangerous Music D-Box's product specifications.

FIG. 1: The D-Box offers analog summing, speaker and input switching, talkback, and a pair of headphone amps.

In the last several years, the trend toward in-the-box computer-based recording and the accompanying decline in the use of the conventional mixing board have spawned several complementary product types designed to provide key functions previously handled by the console. The monitor controller, for example, gives you necessary features such as talkback, input switching, speaker switching, and headphone amplification. Another postmixer product is the analog summing box, which allows you to combine a number of subgroups, stems, or individual tracks from the outputs of your DAW into a stereo mix that is summed through analog circuitry.

Dangerous Music, a company that is a leader in the analog summing field and also makes top-notch monitor controllers (the Dangerous Monitor and Monitor ST), has incorporated the technology from both types of units into the D-Box (see Fig. 1), which contains a D/A converter as well. To make the deal even sweeter, the unit offers the renowned Dangerous Music audio quality at a price that will appeal to the personal-studio market. (The D-Box received a 2008 EM Editors' Choice Award in the Ancillary Hardware category.)

The D-Box is a single-rackmount device, with all of its knobs and switches on the front panel, and all of its plentiful I/O, with the exception of the headphone outputs, on the back (see Fig. 2). It's very solidly built, with a heavy-duty metal case, metal knobs, and plastic push-button switches that light when engaged.

Functionality

I'll cover the D-Box's main functions one at a time, beginning with speaker switching. On the back panel you get two sets of left-and-right XLR speaker outputs, which can feed main and alternate monitor pairs. To switch between them, simply press the Alt Spkr button on the front and it will light, indicating that the switch has been made. A Mono button is also included, so you can check the mono compatibility of your mix.

FIG. 2: Most of the D-Box’s I/O is on XLR jacks, with the exception of the eight summing inputs, which are on a DB-25 connector.
The Summing Input allows you to combine up to eight analog outputs from your audio interface.
Though labeled DAW and CD, the two digital inputs are functionally identical and are compatible with both AES/EBU and S/PDIF sources.
The summed audio is available from this XLR stereo pair for connection to a 2-track recorder or into a stereo track on your DAW.

I have three sets of speakers in my studio, but because the D-Box has only two pairs of speaker outputs, I thought I'd have to work without my third pair. However, the folks at Dangerous suggested using one of the headphone outputs to feed it. (There are actually two separate headphone amps in the D-Box.) Switching to the third speaker pair required me to turn the master volume control down and the headphone knob up, but the method worked well, and the speakers sounded fine when driven by the headphone output.

Switching In

The D-Box's input switching provides plenty of options. You get two digital inputs, one labeled DAW and the other CD. Despite their names, both inputs are functionally the same and can be used with any AES/EBU or S/PDIF source. The input senses which format it's receiving and sets itself accordingly. The D-Box's D/A converter offers excellent quality.

On the analog side, you get a stereo pair of inputs on XLR jacks, and an input for the eight channels of summing on a DB-25 connector. Plan to spend some additional cash on cabling, because you'll need a DB-25 breakout cable to go from your audio interface's individual outputs to the D-Box if you want to use the summing function. (Figure on spending at least $50 for such a cable.) If the digital gear you'll be connecting to the D-Box has S/PDIF outputs with RCA connectors, you'll need adapter cables that end in male XLRs on the D-Box end. (Thanks to Redco for providing cables for this review.)

In its default state, the D-Box lets you listen to only one input at a time. However, you can change this when you put the unit into Setup mode, which allows you to select either or both of two optional functions: monitoring multiple input sources simultaneously and increasing the gain for the Analog Input (which is normally set to +4 dBu) by 11.7 dB. This will let you accommodate gear with -10 dB consumer outputs.

Having four inputs gives you lots of flexibility for A/B comparisons. For instance, you can check the analog Sum Output against your mix as routed through your interface's digital outputs, and you can A/B your mix against other sources coming through either the digital or analog inputs.

Talk to Me

For talkback, a small mic is built into the front of the unit, and pressing the TB button turns it on, letting you speak to those listening through the headphone outputs. The mic button is of the Momentoggle variety; that is, if you press and hold it, it will turn off when you release your finger. If you press and release it quickly, it will stay engaged. So if you want to give an extended soliloquy to the talent from the control room, you don't need to keep your finger on the button. Be careful, though: this feature opens you up to accidentally leaving the switch engaged and thus inadvertently letting the talent hear not-so-flattering control-room chatter (such as “When should we give up and call in the session singer?”). You can also control the talkback mic with a standard footswitch, which is not included. Any switch that when pressed shorts the tip to the ring (or sleeve) of a ¼-inch jack will work.

The D-Box contains a pair of headphone amps, one for each headphone output. Each output has its own volume control and can supply plenty of volume for the cans. One drawback compared with some other monitor controllers (including Dangerous's own Monitor and Monitor ST products) is that there is no dedicated cue path, so you can't feed the talent a different mix from the D-Box than you're listening to in the control room. The headphone amps and the speaker outputs are both fed by what's coming through the selected input (or inputs). Of course, your audio interface most likely has a headphone output, so you could run a separate feed from it as a work-around, but then you wouldn't be able to utilize the talkback function.

Sum of the Time

Space constraints prevent me from going into the controversial issue of analog versus digital summing. (For a full examination, see “The Sum of All Tracks,” available at emusician.com for Audio Insider members.) Regardless of your opinion on that, however, it would be hard to argue with this statement: the sound quality you get through the D-Box's summing circuitry is excellent.

Here's how it works. The D-Box's summing feature allows you to combine three stereo pairs and two individual, pannable outs (channels 7 and 8, which also can be panned hard left and right and used as a fourth stereo pair if you want). These two mono channels with pan pots are there so you can route individual tracks through external processing (for example, an outboard compressor for the vocal track and an EQ for a guitar solo) inserted between your audio interface and the D-Box, and then set their pan positions for the mix.

Deciding which tracks to route through which outputs will depend a lot on what's in your particular project. Bob Muller from Dangerous suggests this simple approach: drums through one pair, guitars through another, vocals though the third, and everything else through the fourth. “Everything else” should include your aux effects tracks (like reverbs and delays), or they won't end up in your mix.

After passing out of your interface and through the DB-25 cable into the D-Box's summing inputs, the first thing that happens to the signals is that they're brought down in level 6 dB by input receiver amplifiers, and then they pass into the summing circuitry. According to Muller, this reduction of level at this point in the gain staging provides additional headroom and a lower noise floor, allowing you to slam those summing inputs with as much level as you can get from your individual DAW tracks (within the context of your mix, of course). By doing so, you can get as much resolution as possible from the digital signals before they hit your audio interface's D/A converters and pass into the D-Box.

The D-Box's circuitry adds back that 6 dB (bringing it back to unity gain) when the Sum Output knob, which controls the level going to your 2-track recorder or mix-track inputs on your DAW, is turned fully up. However, Muller recommends starting your mix with the output knob at 12 o'clock and then turning it up or down as needed, depending on the levels of your mix. I tried this and found that I usually ended up pushing it up to about 2 or 3 o'clock in order to get the ideal level into the A/D converters for recording the mix back into my DAW.

Another way to think about the D-Box's summing feature is that it lets you send your digital tracks through what's essentially a quality analog mixer without the knobs (and with much shorter signal paths). Because your faders and panners are in your DAW, the D-Box doesn't impact your ability to totally recall the mix in software (unless you use the panners on channels 7 and 8).