Issue 60
Read Next:

ARX USB D.I. — AudioTechnology


March 20, 2008


The mini-jack was never meant to be a pro connector. And now it doesn’t need to be.

Text: Trevor Cronin

ARX’s ‘Audiobox’ range of compact problem solving products has been a real godsend. They’re a bit like Swiss Army knives for audio guys (only they’re blue). The range including D.I. boxes, splitters, earth lifters and many other useful doo-hickeys. The unit reviewed here is the new USB D.I. Its claim to fame? It gets the audio from a client’s laptop computer into your professional audio system quickly and reliably.

If you’re in the AV business you’ll know immediately that ARX has hit on something here. Computers are increasingly presentation tools and more often than not the sound needs to be taken from their flimsy mini-jack headphone connectors. This is then plugged into a couple of D.I. boxes via a (hard to source) mini-jack to 2×1/4-inch adaptor cable; a method that’s often fraught with danger – the mini-jack isn’t particularly reliable a connector and the onboard audio quality/conversion is often below par.

Most operators can recount tales of disaster where the laptop audio has been intermittent. It’s not a good look to see the AV tech interrupting a presentation, armed with a roll of Gaffa tape and a can of contact cleaner, or worse still, barking instructions to “wiggle the plug a bit” when the sound gets particularly dodgy! That’s not what we call ‘Pro Audio’ and the AV tech generally has enough on his or her plate during a conference without this gremlin rearing its ugly head!

Enter the ARX USB D.I. Audiobox. This little blue box plugs straight into a spare USB port on a computer – an action normally instantly recognised by the system’s software, which then simply prompts you to select the unit as the default audio output device.

OSX/Windows generally does this all by itself – it’s genuinely ‘plug & play’, as it were. Confirmation that all’s well between the Audiobox and the computer is, at this point, indicated via a bright green glowing status LED. Nice and simple, just like plugging in a USB stick; no drivers required. The computer’s audio now comes out via the USB D.I. and is connected to the audio system via XLR mic cables; a setup that’s streets ahead of anything involving a mini-jack connector. I can hear the collective sigh of relief from here!


The ARX USB D.I. is constructed using a robust folded sheet metal housing, powder-coated dark blue. The high-quality, gold-plated USB In and XLR Out connectors and the aforementioned status LED are all located at one end of the unit, and all are partially protected by the overhang of the top of the box – a nice touch. The sides of the D.I. box even have Kensington-style laptop anti-theft security slots; perfect for those unattended installations. I actually used this to cable tie the USB lead to the unit (one less cable to remember when setting up).

Inside the unit, alongside the D/A ‘brain’, are a couple of hefty isolation transformers, which make the audio path clean as a whistle, providing protection against hums and buzzes that could otherwise be induced into the audio path from external sources. The unit uses quite a few metal screws and plenty of hot melt glue to hold it all together. It looks robust enough and will almost certainly survive the rigours of the road for years to come. One thing to note is that the ARX USB D.I. is not intended for use with domestic hi-fi equipment and therefore offers no RCA connectors of any kind.


I first fired up the USB D.I. at the AV Partners warehouse on sunny Hamilton Island. The source computer was a low-spec Compaq Armada laptop running Windows XP and Media Player. The D.I. was recognised immediately and provided a clean and clear audio output of a nominal –10dB level. The user manual recommends turning up the computer’s mixer level to ‘maximum’ for optimal audio quality. As it was, the level was perfect for our purposes and gave the required drive down a 75-metre multicore into the front end of a Tascam digital console that we were configuring for conference music use. If the unit produced a hot +4dB level there could be issues with cheaper mixer preamps that have a lack of headroom. As it is, there’s not much chance of distortion.

Since this initial test I’ve used the ARX USB D.I. for six months in a multitude of applications with Mac and Windows desktops and laptop computers, and in all that time, the unit has performed faultlessly.

This recent addition to the ARX ‘handy blue gadgets’ line is sure to be well received by AV companies around the world as a great little problem solver. Now if ARX only made a little blue box to sort out a video feed that works on all computers, the life of an AV tech would be a piece of cake…


Leave a Reply

Your email address will not be published. Required fields are marked *

More for you

Issue 60