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ART Voice Channel

Vocal Recording Channel & USB Audio Interface
Published July 2009
By Mike Senior

A glance at the front panel shows a bewildering number of controls. The intuitive layout includes large, clear metering for the hardware processor and the audio interface.A glance at the front panel shows a bewildering number of controls. The intuitive layout includes large, clear metering for the hardware processor and the audio interface.

This budget recording strip is certainly a jack of all trades, delivering a huge feature set for the price — but does it offer quality as well as quantity?

Applied Research and Technology have long been well thought of within the project studio fraternity, by virtue of their wide range of fully‑featured analogue processors, including some with valves, at comparatively low cost. Their new Voice Channel processor under review here is a case in point, managing to offer a mic/line/instrument preamp, compressor, de‑esser, expander/gate, EQ, and multi‑format A‑D conversion for comfortably under £500$450. What is particularly impressive is the amount of control you get, a total of 17 knobs and 10 buttons to tweak in search of your ideal sound. To avoid this review getting too bogged down, however, I've detailed all the main features in a 'Vital Statistics' box elsewhere in this article, so that I can instead concentrate on how well these features fit together, and how good they sound!

Preamp & EQ

While mic signals can be plugged into either of the two combi‑jack/XLR input sockets, a jack connected to the front‑panel input will see a high impedance suitable for instruments, and a rear‑panel jack connection will see a lower impedance suitable for line‑level sources. The preamp's 60dB mic gain is already pretty decent, but the provision of a further 20dB gain on the pre‑conversion output level control means that distant miking with ribbon mics becomes more feasible.

The sound of the preamp is, of course, the primary concern with any voice channel, because no matter how good any subsequent processing, you're limited to the quality captured in the first place. ART have a lot of experience in this area, so it's no surprise that the performance presents good value at this price point: you get a fairly clear sound, with very little noise and a certain amount of 'air', and as such this unit should handle the majority of small‑studio tasks capably. This isn't a neutral preamp, though, and even with the valve voltage and input impedance set high to deliver a cleaner tone there's still a forwardness in the mid-range that works better on some sounds than others; you'll be able to enhance any slightly 'pillowy' mic signal, but anything that's already delivering hardness may become a bit brittle. For vocals, this will likely suit breathier singer‑songwriters, under-powered rock gods, and badly enunciating rappers, but stadium‑worrying belters are likely to end up sounding thin and wiry.

Turning down the input impedance was quite effective at mellowing the mid-range character, but rather at the expense of the airiness, I found. Turning the valve voltage-level down emphasised the valve sound, as expected, and although this didn't lessen the midrange prominence it did balance it with more of a sense of typical low mid‑range valve thickness. Even at the low plate voltage, though, the valve sound didn't seem as full‑on as with some other budget valve units I've tried — I compared it side‑by‑side with the Dbx 376, for example, which seemed to take things further in this respect. As I've said, this still isn't a preamp to choose if transparency is what you're looking for, and as such I found things like acoustic piano tricky to capture with an even‑sounding tone, especially as the real low end of the ART felt a bit thin in all modes, a shortfall fairly typical of more budget‑friendly valve designs. To be honest, I'd suggest that solid‑state preamps will probably do you better in the price range for more challenging work, albeit with less flattery on some sources.

For me, the strength of the Voice Channel's EQ section is as an audio problem solver, where its well‑contained swept mid peaks and dual‑frequency shelves provided a tremendous toolbox for ironing out overprominent spectral regions. In this respect, the unit put in a good performance with challenging sources such as acoustic guitar and upright bass, where the ability to home in with precision on unwanted resonances and mechanical noises was an asset. Switching the EQ pre/post‑compressor was also useful in this role (even more expensive products often choose one position or the other). The gain range in each band might seem a bit small to some users, but I'm inclined to think that if you need more than 12dB of EQ either way you've probably got your mic in the wrong place anyway...

Using this EQ to aim for more subjective tonal goals proved more daunting, however, because boosting with any of these ART filters tended to result in a hardening of the sound that was frequently rather unforgiving, and only really appealed to me for some drum and percussion parts. This isn't really an EQ I'd turn to for some kind of 'analogue magic' on vocals or acoustic instruments, and I found myself following a fairly restrained 'cuts only' approach to get the best out of the Voice Channel on such sources. I also felt that the EQ circuit itself seemed to be blurring the frequency spectrum a little even when all the controls were nulled, so I'd be more than usually inclined to switch it off completely with its dedicated bypass button, unless serious troubleshooting were required.

Compressor, De‑esser & Expander

A similar, workmanlike rather than artistic quality seems to me to pervade the compressor block too, where again you get a lot of control — certainly enough to do serious sculpting of drums, clean guitars, and electric bass. Even at the fastest attack and release times, the gain changes seemed to stay fairly well under control, and distortion of bass instruments remained commendably low. A good range of ratios is offered, which is nice, although you need to drive the preamp quite hard if you're going to get very much action out of the most subtle ratios.

Where the compressor doesn't seem to do quite as well is with vocals and sustained solo instruments, where a softer compression curve and more intelligence in the attack/release characteristics would have given a more musical result. Although I could rely on this box to control the dynamic range of such sources to order, it was a bit of a struggle to keep the processed part sounding natural at the same time. A minimum‑processing approach therefore proved once more to be optimal most of the time. You can always compress more firmly during mixing if obvious compression effects suit your musical genre.

An unexpected bonus for me was the Voice Channel's de‑esser, which turned out to work really well. As far as I can figure out, it appears to function by adding a tunable EQ peak to the compressor's detector side‑chain, thereby triggering more compression during sibilance. What impressed me was that the processing seemed to be practically immune to lisping — which is quite an achievement — and as such I'd be much more inclined to de‑ess even while recording, which I'm normally loath to do (if your recorded vocal is lisping on the way in, the problem can prove a hard nut to crack at the mix). The Expander/Gate section gives you a fairly fast attack and release, and the limited control set is fine for general noise‑suppression tasks, assuming that you need to tackle those in the analogue domain.

Ins & Outs

As regards the digital output options, there's lots of flexibility, although I'm not sure how likely it is that anyone selecting doubled or quadrupled sample rates will stick with a 16‑bit word length, as you can here. The A‑D conversion seems pretty clear overall, and certainly more than up to the quality level of the rest of the unit, although the low frequencies did appear to thin out slightly when I looped files out of the outputs of my Drawmer DC2476 mastering unit back through the Voice Channel's A‑D conversion.

The rear panel hosts a variety of I/O, both analogue and digital.The rear panel hosts a variety of I/O, both analogue and digital.

That the USB socket offers a way to get audio directly into your computer system without a separate interface is beyond doubt. However, ART provide no dedicated low‑latency driver, and because the Voice Channel has no playback monitoring facilities of its own, Windows users may need to download a third‑party multi‑device audio driver to record via the Voice Channel and listen back at the same time.

Mac users can rely on Core Audio to co-ordinate the Voice Channel with any other audio hardware on their system, and while Core Audio apparently provides pretty good latency performance in general, latency proved to be a problem on my PC system. In Reaper, which supports multi‑device operation using the plug‑and‑play windows drivers, the latency delay was large enough to feel like a permanent slapback echo, while in Cubase, under Michael Tippach's freeware universal multi‑device driver, ASIO4ALL, I still couldn't get the latency any lower than 27ms. Even at this kind of latency, software monitoring choruses obviously with direct spill, and timing feels distinctly sluggish. In short: don't expect to use software monitoring with the Voice Channel unless you've checked that the latency is acceptable on your system.

But Is It ART?

Where ART have always scored strongly is in terms of price/features ratio, and this unit presents phenomenal value in that respect. If you need a lot of control for tracking a wide variety of different instruments and vocalists, the Voice Channel's parameter‑rich multi‑processing will make sonic problem‑solving a great deal easier. Abundant socketry, decent onboard metering and built‑in, highly configurable A‑D conversion also mean that this unit can fulfil a very broad range of studio functions, because you are able to pass signals through the preamp, processing, and conversion sections pretty much independently of each other if you like. The only area where ART seem to have missed a trick in terms usability is with the USB interfacing, which feels like an afterthought because of a lack of proper low‑latency drivers or any Focusrite Platinum‑style analogue monitoring facilities.

Where the Voice Channel will encounter its sternest competition, however, is amongst users who are happy to leave in‑depth audio processing until mixdown, and are most concerned about the quality of the capture and the ability of any processing to subjectively improve the audio tonality in some more musical way. Given that the compressor and EQ here are much better at problem‑solving than enhancement, those computer musicians who already have some respectable plug‑in processing would be better advised to look into buying a simpler stand‑alone valve preamp/converter where the manufacturer's investment per component is likely to be higher. Even where analogue processing is required, I'd still probably choose a less fully‑featured unit over the ART for recording work, on grounds of both subjective sound and speed of on‑session setup.  


At this price, the Voice Channel is well‑nigh unbeatable in terms of pure features. About the closest you'll get is Focusrite's Platinum Voicemaster Pro, which provides a roughly comparable level of raw functionality, but at a higher price if you include its optional digital converter card. However, you shouldn't write off this Focusrite unit, because included in its price you also get analogue monitoring facilities (including a headphone preamp), which can be a very useful extra for cash‑strapped studios suffering from latency problems.

The main reason to explore alternative options is if you're happy to trade off features for the potential of higher‑grade sonics. Toft Audio's EC1, Drawmer's MX60 and Dbx's 286a all provide multi‑processing within budget, for example, but without the valves or onboard A‑D conversion, and all have been well‑received in former SOS reviews. Valve multi‑processing is available a bit further up the price range if you still want the tube sound, and here I'd consider units like the SPL Track One, TL Audio 5051 or Dbx 376.

Vital Statistics

Analogue I/O: Parallel analogue Combi‑jack/XLR inputs, on front‑panel mic/instrument and rear‑panel mic/line sockets; unbalanced post‑preamp insert jacks; balanced jack and XLR outputs; pre‑conversion TRS inserts on digital channels.

Digital I/O: AES‑EBU XLR out; S/PDIF out (co-ax); S/PDIF or ADAT out (lightpipe); BNC sockets for Word Clock input and thru connections; additional optical input for synchronising with ADAT machines; USB 1.1 connection for direct audio output to computer recording systems.

A‑D Converter: 16/24‑bit, 44.1-192kHz via AES/EBU or S/PDIF; 32kHz, 44.1kHz, or 48kHz over USB; 20‑segment LED digital meter with simultaneous RMS/peak display and clip indicators.

Mic/Instrument Preamp: Valve gain stage with two‑position selector switch; 0‑60dB gain, with additional 20dB on output fader; mic input impedance variable between 150Ω and 3kΩ; switches for 48V phantom power, polarity inversion, and 100Hz 6dB/octave low‑cut filter.

Dynamics: Compressor with 1:1 to 20:1 ratios; 250µs‑100ms attack times; 100ms‑3s release times; 20‑segment LED gain‑reduction meter. De‑esser with sensitivity and frequency (2.5kHz‑15kHz) controls; switchable expander/gate with variable threshold and activity LED.

Equaliser: Four‑band semi‑parametric design, switchable pre/post dynamics; +/‑12dB gain in all bands; low and high shelves switchable between 50Hz/150Hz and 5kHz/15kHz respectively; sweepable mid‑band peaking filters cover 100Hz‑3kHz and 500Hz‑15kHz respectively.

Published July 2009