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Dangerous Music Source

Portable Monitor Controller
Published June 2013
By Hugh Robjohns

Dangerous Music Source.

Meet the monitor controller for the DJ, musician or engineer on the move!

US-based Dangerous Music have a reputation for producing high-quality but relatively affordable products, such as monitoring controllers, analogue summing buses and mastering insert switchers. The credo upon which chief designer Chris Muth operates is that audio integrity is non-negotiable, and all Dangerous Music products place the emphasis on maintaining transparency and headroom when used in real-world applications. Muth also believes that if it's complicated on the inside it should be easy to use from the outside! The Source, the latest addition to their monitoring line, is focused on minimal size and portability, without sacrificing technical quality or, indeed, versatility.

Form & Function

Aimed particularly at musicians, producers and DJs on the move, the Source provides studio quality and features in a compact format that sits neatly beneath a laptop (it fits perfectly under a MacBook Air, in fact!). It should be pointed out from the outset that this is more a D-A converter and multi-output signal switcher than a true monitor controller, in that it lacks many of the facilities traditionally associated with the latter. While this will inevitably reduce its appeal to some, the facilities that are provided are very flexible; this flexibility, along with the sheer audio quality and price, means it will appeal to many others.

Measuring 325 x 45 x 205mm (WxHxD), and weighing just over 2kg, the Source can be carried around reasonably comfortably in a laptop bag — and that's the point, really. The only negative aspect of its size is that the two volume control knobs stick out about 20mm from the front plate, with no protection. An optional rackmount kit actually comprises a replacement front panel, which makes the unit look like a purpose-built 19-inch rack product, rather than a desktop unit with bolted-on side wings.

In terms of connectivity, the Source includes two stereo analogue inputs, a digital AES3 input, and a USB input. The primary analogue inputs are on combi XLRs, accepting either balanced (on XLR or TRS plugs) or unbalanced (on TS plugs) signals with a nominal +4dBu operating level. The secondary analogue inputs are connected via a 3.5mm unbalanced stereo mini-jack socket — not a professional format, perhaps, but it's what's needed in the real world of smartphones providing reference tracks! Interestingly, the factory default is for a nominal input level of -16dBV, this apparently being the typical output level from an iPod or iPhone. However, internal jumper links allow the sensitivity to be switched to the industry standard -10dBV.

The AES3 digital input (24-bit, 32-192 kHz) uses an XLR, which will also accept an S/PDIF signal via a suitably wired cable. It's also equipped with a direct loop-through output on another XLR, which is handy if you have a mic preamp with a digital output, as you can monitor that output through the Source while passing it on to your recording device. The class-compliant USB connection also supports sample rates up to 192kHz and 24-bit, and is driverless for Mac OS 10.6 and above. The Source interface is listed amongst the computer's audio output options as an 'XMOS USB 2.0 Audio Out'. Windows 8 users need to download a small CEntrance driver from the Dangerous Music web site, although apparently it's not (yet) compatible with Windows 8, which is a little disappointing. Once the driver is installed, the Source interface is again listed as an 'XMOS USB 2.0 Audio Out' in the PC's audio options. Both the AES and USB inputs slave automatically to the source sample rate, so there's no clocking or synchronisation to worry about. We're talking standard core OS drivers here, not ASIO, and the latency seems to default to 10ms, which is adequate in many cases.

Outputs comprise two switchable speaker outputs (one on XLR, the other on TRS), a fixed-level stereo analogue line output derived from the selected speaker source, and two paralleled headphone sockets on the front panel. As shipped from the factory, the speaker outputs are attenuated by 6dB to provide the gain structure required by most active monitors, but can be reset for unity gain by removing some internal jumper links. All the speaker and line outputs are active, symmetrically balanced, and capable of driving +26dBu into a 600Ω load.

The range of I/O on the rear panel is well thought-out for a portable device, and includes both a USB interface and mini-jack input for devices such as smartphones.The range of I/O on the rear panel is well thought-out for a portable device, and includes both a USB interface and mini-jack input for devices such as smartphones.

The one minor connectivity niggle is that power is provided by an external wall-wart (delivering 12VDC at 2A), both to help keep the unit small and portable, and to ensure ease and low cost of replacement. That's perfectly acceptable, given that the unit internally generates ±18V power rails, but the PSU is connected via a non-latching coaxial power plug with no cord retainer, which would have been a simple and useful addition. Making up for this to some extent is a second identical power socket wired in parallel, which is intended to pass power on to possible future accessories — a prospect that's both intriguing and exciting!

A Poke In The Ears

Comprehensive as the Source's I/O is, it doesn't reveal the full story of what Dangerous Music have actually provided here. For a start, the headphone outputs are driven by a surprisingly hefty headphone amplifier. So powerful, in fact, that the manual includes several warnings about the risk of hearing damage! It's certainly capable of going very loud indeed and had no trouble driving all of my headphones (24-150Ω varieties) to uncomfortably loud levels with no hint of transient distortion or compression. In the modern world of enforced 'nanny state' protection for the benefit of idiots, it's nice to see a company that trusts users to know what they're doing. How very refreshing!

Also unexpected was that the Source incorporates independent D-A converters for the AES and USB inputs, so that both can be auditioned independently or simultaneously. This is unusual; most controllers have just one D-A, which is switched to the selected digital source. In fact, any (or all) of the analogue and digital inputs can be auditioned individually or in combination, and the headphones' source selection is entirely independent of the speakers' selection. This makes it possible for a performer to hear one combination of sources while the engineer/producer listens to something else. If the I/O connectivity suits, you could even use the ability to mix the two analogue inputs with the AES and USB inputs (at fixed unity gain) as a kind of summing bus, outputting to the line-level outputs — I did say it was flexible, didn't I?

While on the subject of flexibility, the line output feature makes it very easy to dub from one device to another, such as from the computer to a backup recorder or sampler. These outputs can also be used to feed a dedicated hardware metering system, an external headphone amp, or a second monitoring setup in a separate room, for example. Further versatility is bestowed by the two sets of speaker outputs; although they are intended to provide alternate monitoring between main and 'grot box' speakers, they can be configured to work simultaneously. This enables the second output to be used to feed a subwoofer (which can thus be switched on and off independently of the main speakers), or to drive house PA speakers separately from a local monitoring system for a club DJ, for example. Versatility and flexibility are definitely the key words when describing the Source's design and potential applications.

In Control

Of course, all this versatility and flexibility calls for a very complicated control panel, doesn't it? No! The front panel is surprisingly simple. There are two full-size headphone sockets on the left-hand side, with four illuminated push-buttons to select the headphone source (AN1, AN2, AES and USB), and a rotary level control to adjust the headphone output level. Four more illuminated push-buttons select the same four sources independently for the speaker outputs, with a second rotary level control to adjust the speaker output level. A final pair of illuminated buttons selects the speaker output destination.

By default, the push-buttons operate with a 'toggling' action. For example, if the AES input is selected to feed the headphone output, pressing the AN1 input button briefly will switch instantly to the primary analogue input source and stay there. Similarly, pressing the Spkr2 button will toggle the speaker output over to the second set of speakers and mute the first, allowing A-B switching between two sets. This is all very conventional, but when held depressed for more than a second, the buttons' behaviour becomes momentary instead, so that an input or output selection, for example, stays selected only until you release the button. In the situation described above, pressing and holding the AN1 button causes the primary analogue input to be selected simultaneously and mixed with the AES input, until you release the button, when the Source will revert back to monitoring just the AES signal.

This arrangement allows for some interesting possibilities. For example, although the Source doesn't have a built-in talkback mic, talkback can easily be implemented by connecting the output of a talkback mic preamp (or even a smartphone running a talkback mic app!) to one of the analogue inputs. Simply pressing and holding the corresponding input selector button on the headphone selector causes that talkback signal to be mixed with the currently selected headphone monitoring source(s), allowing direct communication with the artist. Release the button and the talkback is switched off. It's a very quick and easy way of setting up console-style working.

Configurable

As is often the way with Dangerous Music's products, there are some hidden configuration options, and to that end the front-panel graphics include a 'Setup' label below the headphone section's AN2 and AES source-selection buttons, along with orange rings around the AN1 input buttons on both the headphone and speaker source selection buttons, and around the SPKR1 button in the output selector. The Setup system works in a very straightforward way: pressing and holding simultaneously the headphone section's AN2 and AES buttons enters the Setup condition, whereupon both buttons blink. Pressing the AN1 button in either the headphone or speaker sections then changes the current switch mode (for that section only) between the default toggle setting (AN 1 button unlit) and the permanent 'latch' setting (AN1 button illuminated). With the appropriate selection made, pressing either of the blinking buttons exits the Setup condition. Job done!

When reconfigured to work in the latching mode, a selected input (or output) stays selected until manually deselected. There's no need to hold the button down to access the source, as in the default toggle mode. This makes it more practical to select multiple input sources permanently, whereupon they mix together and can be auditioned simultaneously. It therefore becomes very easy to configure the system so that, for example, a performer can hear the output from his or her vocal mic preamp along with the backing track replayed from the computer, to create latency-free cue monitoring on the headphones.

The same toggle or latch options are available for the speaker outputs, and are adjusted in the same way by entering the Setup condition and then pressing the Spkr1 button to change mode. Switching to the latching mode allows both speaker outputs to be used simultaneously, for instance, when wanting to drive a subwoofer independently, with the ability to turn it on and off without affecting the main monitors, or to drive local and remote monitors simultaneously.

Hands On

The Source is very sturdily constructed and comes with a two-year warranty. All the knobs and buttons have that weighty, solid feel that exudes a sense of quality and reliability. The button illumination is also bright enough to let you see what's selected, but not so bright that you need to wear sunglasses when operating it!

From a sound-quality point of view, the Source has excellent technical specifications and the circuitry is similar to the DC-coupled designs of other Dangerous Music monitor controllers. Measuring the primary analogue input to any of the analogue outputs exhibits a flat bandwidth within 0.5dB all the way from 10Hz to 80kHz. The maximum input and output levels before clipping are an impressive +26dBu, and at nominal +4dBu operating levels the THD+N distortion and noise figure is 0.0025 percent. The noise floor (with a balanced input) sits at around -93dBu (unweighted), giving a total dynamic-range capability of around 119dB, which is comparable with that of most decent D-A and A-D converters. What you hear through the Source is definitely what is coming from the selected source, with nothing added and nothing taken away. The unbalanced AN2 input's noise floor is a couple of decibels higher than the balanced AN1 input, and the bandwidth is slightly curtailed at the high end (-0.5dB at 50kHz), but that's not likely to be noticeable to anyone in practice, especially given the typical quality restrictions of your average smartphone!

Hooking the Source up to my laptop running 32-bit Windows Vista was trivially simple after I downloaded and installed the driver file, and it seemed to operate by default with a 10ms latency. I connected a pair of review Neumann KH0310 monitors to the Spkr1 outputs, selected USB as the speaker source, and turned up the output level — job done! Everything worked exactly as you'd expect, with a sensible level setting on the output level control giving a sensible replay level from the monitors. I plugged an iPod into the AN2 input and was able to audition reference tracks without needing to mess with the monitoring level too much, so the gain structuring seems well judged.

The Source lacks traditional monitor controller facilities such as Mono, Phase (polarity) and Dim switches. A more comprehensive monitor controller would also allow the relative levels of different sources to be adjusted, to make A-B switching more accurate and objective. The fact that the Source doesn't include these features is simply due to size and cost constraints. However, as a compact, high-quality source switcher and D-A for monitoring the output of a computer — perhaps for editing or pre-production work on location — the Source is, quite simply, superb. It easily matched the resolution, transparency and detail of my reference monitor controllers (Benchmark DAC1, Grace Design M902, Crookwood M1 and Bryston SP1.7).

As a flexible device for setting up a separate monitor mix of multiple sources (including latency-free monitoring) for a performer, while still allowing independent speaker monitoring, the Source is very versatile. It also provides sensible headphone drive levels that work in the real world. OK, it's not a fully fledged monitor controller or a low-latency recording interface, but it is an extremely high-quality and surprisingly flexible monitoring device that's very compact and cost-effective. With both analogue and digital sources, and via the speaker, line and headphone outputs, it also sounds effortlessly transparent and accurate, yet still musical and enthralling: all the characteristics that define top-flight analogue circuitry. The bottom line is that the Source is a great, reference-standard, versatile monitoring switcher!

Alternatives

Although there's nothing directly comparable in terms of form factor or functionality, monitor controllers with independent artist cue facilities include the Presonus Monitor Station (roughly half the price), and Dangerous's own Monitor ST (twice the price!).

Published June 2013