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ARX Sixgate & DI4

6-channel Gate & DI Box
Published July 1999

ARX Sixgate & DI4

Nicholas Rowland plumbs in a couple of handy studio tools from the other side of the globe.

"Australian for pro audio" is how ARX define themselves — and as the only other Antipodean audio company I've ever heard of is Fairlight, I'm not in a position to argue. Though not that well‑known here in the land of the whingeing Poms, ARX has been established down under since 1983 with a growing range of products aimed at the studio, sound installation/reinforcement and broadcast markets.

ARX was originally formed by a couple of sound engineers who couldn't find certain products to meet their needs and so decided to make their own. Indeed, another ARX marketing war cry is "we only build equipment that we'd like to use". So while the ARX range now takes in signal processors, amplifiers and speaker systems, the company pride themselves on what they call innovative problem‑solving products, an ethos which is exemplified by the two items on test here.

Mine's A Six‑Pack

ARX Sixgate & DI4

I'd be failing in my duty if I didn't point out that the first of these, the Sixgate is not exactly new. In fact, it first appeared in 1987, since when it has been one of ARX's most successful products (particularly after its original bronze‑and‑cream colour scheme was changed to a more sombre black and blue). Nevertheless, despite its age, it's still worth taking a quick look at here — repackaged now in ARX's standard and rather more eyeball‑pleasing silver‑grey livery — simply because it remains a relatively unusual configuration.

The logic behind the Sixgate comes from live audio applications. ARX asked the simple question 'What do most people use gates for?' — and the simple answer came back 'Drums, drums and more drums'. Add up a snare, kick drum, hi‑hat and three toms and what do you get? A requirement for six noise gates, which ARX have duly squeezed into a single unit of rack space. Along with drums, the Sixgate has also found a niche in non‑musical applications too, such as control of conference mics.

The unit is very much no‑frills. All channels have the same front panel controls — a knob each for Release, Depth and Threshold, a red and green status LED to indicate whether the gate is open or closed and a hardwired in/out bypass switch. The Threshold control ranges from ‑50dB to +10dB, while release times can be varied between 100ms and 2 seconds. Depth (0dB to ‑40dB) controls the 'height' of the gate — in other words, how much signal and/or unwanted noise is actually held back when the gate is closed. This can be useful when, say, gating live vocals because by allowing a certain level of background sound to 'leak' through the gates when they're shut, voices don't sound like they come out of nowhere when the gate opens, nor do you get the effect of the gate 'slamming' suddenly shut.

Attack times are determined automatically according to the incoming signal, using circuitry based on a proprietary opto‑isolated design which tracks the incoming signal to determine optimum gate response. I scoured the literature in vain to find some indication of the range of attack times on offer. While some engineers may bemoan the lack of a dedicated attack control, it's something I can live with simply because it makes setting up so much easier.

A six‑pack's worth of connections can be found round the back with each channel featuring balanced/unbalanced in/out connections on TRS jacks, plus key inputs on jacks so you can control the operation of the gate via an external signal — enabling you, for example, to employ the standard trick of locking the timing of an instrument like a bass guitar into the beat of the bass drum. Each key input also doubles as the insert point for the gate's sidechain (wired tip in/ring out, sleeve earth/ground) enabling frequency‑sensitive gating — you can, for instance, reduce the gate's sensitivity to higher frequencies such as crash cymbals by inserting a low‑pass filter.

Placing the DI4 in my recording room meant that its mixing functions could be used to create monitor mixes without intervention from the control room.

The ergonomically aware among you might also note that, like all ARX equipment, the Sixgate features an area for labelling with a chinagraph pencil beneath each channel (both front and back in the case of this unit) — a neat touch which I'm surprised hasn't been taken up by other manufacturers. Also available is a security cover which prevents people tampering with settings once they're fixed. And, like its fellow countrymen, the Sixgate loves to travel, with power via an internal transformer which can easily be switched from 100‑120 VAC to 220‑240 VAC operation as required.

And that really is it. In operation, the gates are easy to set up and adjust. I tried the Sixgate with a selection of incoming signals and found that its automatic attack function behaved appropriately in virtually all cases. Though originally designed with drums in mind, the Sixgate is clearly at home with all types of sounds, from spikey percussive transients to smoother, more round‑ended sounds. Automatic gates sometimes have difficulty with material with very sharp attacks, not being quite quick enough to open in time to allow the very front end of the sound through, but the Sixgate seemed able handle these kind of sounds quite adequately. As I mentioned before, when gating vocals it's best to ease back on the Depth control, so the gate doesn't close with too much of a bang, if you get my drift.

Aussies Inject It Direct

ARX Sixgate & DI4

And so on to the DI4 — not the most exciting product in the world, by any means, but one which ARX would humbly suggest might prove to be the most indispensible purchase you've ever made. As its name suggests, the unit is essentially a four‑channel (active) rackmounting DI box, albeit one that also doubles (or maybe that should be 'quads') as a four‑into‑two line mixer. You can also combine the two functions, with some channels going direct and some being routed through the mixer function.

In fact, the DI4 is one of several direct injection solutions produced by ARX. Also in the range are stand‑alone single‑ and dual‑channel models (named the DI1 and DI2 respectively), plus the DI6, which functions as six active DI units, plus a six‑into‑one line mixer, a one‑to‑six splitter and a headphone amp for good measure. If you need a lesson on just why DI boxes are an essential element in every studio then look no further than Paul White's article in SOS April '98. If you don't, then let me remind you that DI boxes earn their keep by matching unbalanced, low‑level, high‑impedance outputs like guitars and basses to the balanced input levels of mixing desks and other pro‑audio equipment.

Each of the DI4's channels features two high‑impedance jack sockets on the front panel. The first of these is an input pure and simple. The second is a looped output which allows you to pass the incoming signal directly on to, say, an instrument amplifier. As well as being useful for live work, this splitter facility could prove handy in a control‑room recording environment when you need to feed a signal to the desk, but want to use the musician's amp either for monitoring purposes or for miking up the cab.

The rotary control for each input offers gain from unity to a healthy +15dB, with a clip LED to show when you're in danger of overcooking. Direct outputs on the back panel are on balanced XLRs, and each channel has an audio earth/ground switch with associated On indication LED. Personally, I think these controls might have been better situated on the front panel, particularly if you're working in a live situation where you're likely to need more frequent access to them than in a fixed studio location. The same comment goes for the buttons which switch channels one and two out of the mix if required (in other words, so their inputs pass straight through to the outputs).

As a mixer, the DI4 boasts the luxury of both balanced outputs on XLR and unbalanced on quarter‑inch jacks. There's a single auxiliary out, with a stereo return, and connections for these are unbalanced. Of course, the aux in can be used to feed a separate line‑level source, effectively turning the DI4 into a six‑channel mixer when required. When using the DI4 in mixer mode, each channel has a pan control, plus an auxiliary send pot. Obviously the auxiliary can also be used to generate a separate mix if required, which could be useful for live applications. Auxiliary return levels are controlled via the knobs on the far right of the front panel, where you'll also find the Left and Right controls for the master output of the mixer.

And that's your lot, cobber. In operation, the DI4 does exactly what you'd expect in terms of handling incoming and outgoing signals. (Incidentally, the impedance figures on these are 2.2MΩ incoming and 300Ω balanced outgoing.) While the figures on the specification sheet are nothing out of the ordinary — Signal‑to‑Noise ratio 96dB, frequency response 20Hz to 20kHz (+/‑0.5dB). and distortion at less than 0.004 percent, 1kHz, +4dB — the DI4 is impressively quiet.

Overall, the DI4 certainly proved its usefulness during its sojourn in my studio, where I have a pressing need to DI electric and electro‑acoustic guitars plus a rather mean and moody bass guitar. Placing the DI4 in the recording room meant that its mixing functions could be easily used to create monitor mixes without needing intervention from the control room — a fact which was certainly appreciated by my mean and moody bass player. I could certainly appreciate how a DI4 could prove a very useful extension to a pub‑size PA set‑up for a small band. Dipping deep into the tombola of clichés, once you've convinced yourself you have a use for a DI4, you may indeed wonder how you ever did without it.


As we round the final bend, I have to confess an interest — an ARX DDD1 compressor has been doing sterling service in my rack for a couple of years now, so I was already favourably predisposed towards these units in terms of user‑friendliness, build quality and integrity of design. Neither of them disappointed. In both cases, they fulfil their allotted task extremely well — the real question is whether or not you have a use for the job they do.

As I said at the beginning, ARX have been a bit under‑represented here Up Above. With their new distribution organisation now in place in the UK, hopefully we'll be seeing a lot more of ARX gear. I'll certainly raise a tinny to that.


  • Easy to use.
  • Well built.
  • There's six of 'em!


  • Some may want more control.


Whether you're dealing with drums or not, the Sixgate is a compact solution to gating in bulk.