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Avid Pro Tools Mbox

USB Audio MIDI Interface By Sam Inglis
Published February 2011

Now that Pro Tools fans can choose any interface they like, do Avid's latest Mboxes offer enough to keep their users in the fold?

After several years during which the Avid product line remained largely unaltered, it was all change in 2010. First we had a new range of audio interfaces for the HD range. Then came the intriguing HD Native card. Then, most dramatically of all, came Pro Tools 9, the first really powerful, hardware‑independent native version of Avid's market‑leading DAW (see our last issue for a review).

By removing the ties between native Pro Tools and their own hardware, Avid created an obvious challenge for themselves. Now that their interfaces are no longer acting as elaborate Pro Tools copy-protection dongles, they have to compete on level terms with the vast array of similar interfaces from rival manufacturers. Perhaps with this in mind, they have revamped their long‑running Mbox series of desktop audio interfaces.

Officially, the successor to the Mbox and Mbox 2 is known not as the Mbox 3, but as the Pro Tools Mbox, which brings altogether too much potential for sentences such as "Unlike the original Mbox, the Mbox supports high sample rates...” I hope Avid won't mind me occasionally sticking the number three on the end to avoid confusion. As before, there are three variants: the Mbox Mini, Mbox and Mbox Pro. Avid supplied the 'mummy bear' of the range for review: for details on the Mini and Pro, see the 'The Other New Mboxes' box.

On The Outside

The Pro Tools Mbox is USB‑powered, with no facility to attach an external PSU.

In physical terms, the Pro Tools Mbox is an impressive beast, its construction dominated by a very substantial metal shell that extends all the way around it. Of course, if you were actually to drop it from height, Sod's Law would no doubt ensure that it landed on its front, from which plastic pots protrude in a slightly less tank‑like fashion, but the overall impression is of a big step up in build quality from earlier Mboxes. It will also be much more difficult to send it flying with an accidental yank on a headphone cable.

The two analogue inputs are each furnished with a combination jack/XLR socket on the rear panel, for line and microphone inputs respectively, and an additional jack on the front panel for direct connection of electric guitars and basses. Both inputs have a pad that is activated by pulling the Gain control outwards, and a Soft Limit button that is supposed to protect hot inputs from digital clipping. A dual-colour LED indicates signal present and clipping, but there is no other metering. Phantom power is globally switched.

The main outputs are on a pair of quarter‑inch jacks, with a headphone output on the front panel. The large main volume control is joined by three intriguing additional buttons labelled Mono, Dim and Multi. The functions of the first two are self‑explanatory — and very welcome — while the latter can take on various different roles depending on software settings.

The main Mbox control-panel page. Monitor reverb can be added using the controls beneath the faders.Like its predecessors, the Pro Tools Mbox is a bus‑powered device, but whereas most previous Mboxes employed the USB 1.1 protocol, the latest one uses USB 2. The much higher bandwidth on offer delivers several obvious improvements. Although it still offers only stereo analogue and stereo digital I/O, they are entirely separate and can be used simultaneously, making the Mbox 3 a true four‑in, four‑out interface. And, unlike the original Mbox, this Mbox supports high sample rates: up to 24‑bit, 96kHz recording and playback are possible with no compromises.

The Pro Tools Mbox also steers a new path when it comes to low‑latency monitoring. On the Mbox and Mbox 2, this was handled in the analogue domain (it still is in the new Mbox Mini): a balance control allowed you to mix some of the input signal into the audio output, so you could hear what you were recording with no delay. This was simple and enabled true zero‑latency monitoring, but it had its negative aspects. For one thing, because you were not hearing the digitised signal, any problems that occurred 'downstream' in the recording path would not be audible until it was too late.

In place of this simple analogue mixer, the Pro Tools Mbox features a digital signal processor. This can not only handle low‑latency cue mixing, but also supplies a guitar tuner and an effects processor, allowing you to hear your input signals with reverb or delay applied. Many singers prefer this, as it can make accurate pitching easier.

Plugging In

The Mbox's surprisingly effective guitar tuner.

The new Mboxes currently ship with Pro Tools 8 and are priced accordingly. Anyone who buys one now will be eligible for a £215$249 crossgrade to Pro Tools 9, and at some point in the first quarter of 2011, the pricing structure will change as Pro Tools 9 is included.

A single driver installer kits your system out with both DAE drivers for Pro Tools and ASIO or Core Audio drivers for other audio applications. You don't get the option of using the Mbox's ASIO drivers in Pro Tools 9, and I can't really see why you would want to.

The Mbox's DSP functions are accessed by a smart little control-panel utility, which is simplicity itself to use. You can directly route any input to any output pair, with its own level, pan and reverb settings. Within Pro Tools, you can cut down the number of trips you need to make to the Mbox control panel by activating Low Latency Monitoring mode. This, in effect, gives the faders on whatever tracks you're recording to control over the levels of those inputs within the Mbox control‑panel mixer, allowing you to make basic cue-mixing moves without leaving Pro Tools.

If you want to use the Mbox's DSP features, however, you'll still need to head to the control panel. Its reverbs and delays are largely preset, but more than adequate for the job in hand. You can choose from a handful of different algorithms, and adjust reverb/delay time and feedback; it might have been nice to have some sort of tone control to minimise distracting sibilance, but in general this is a cake that stands in little need of additional icing. It's a small thing, but I also really liked the Mbox's guitar tuner. Good software guitar tuners are thin on the ground, but this one is accurate and reacts quickly, smoothly illustrating the decay in pitch that occurs when you twang a heavy string. On the down side, you can only tune to A=440Hz.

A nice touch is this flow diagram.The additional control features to the right of the front panel are also very handy. The Dim button lowers the output by 30dB from both the main and headphone outs, while the Mono button does exactly what you'd hope. This is a really useful feature that is absent from a great many interfaces, including many more expensive ones, and Avid are to be applauded for including it here. The Multi button, meanwhile, is a kind of remote control for Pro Tools. It can perform two different functions, depending on whether you press it and immediately release it, or press and hold. Options available in the former case include adding a new track to the Session, moving the cursor to the next or previous marker, starting and stopping record or playback, toggling Loop playback, replicating Pro Tools' Undo or Save options, and allowing you to tap a Session tempo. Press and hold options are the same, except that, for obvious reasons, tap tempo is a no‑no.

It would probably be fair to say that earlier generations of Avid and Digidesign hardware, at least in the LE range, were not known for their top‑flight preamps. So it's pleasing to report that those built into the Mbox 3 are not bad at all. They have a punchy sound, with a 'forward' quality that seemed, to me, to slightly emphasise the upper mids, and, best of all, they have a decent amount of clean gain. I was able to use my ancient Beyer ribbon mics to record vocals and even fingerstyle acoustic guitar, and was pretty pleased with the results. As with many inexpensive preamps, though, the gain controls are not very linear, and the last 6dB of gain or so seems to come in about half a millimetre of travel. Also worth noting is that, as on previous Mboxes, the line inputs also pass through the preamps. This is great if you have old analogue synths that put out weird and unpredictable levels, less good if you want to accurately transfer a stereo signal from another source.

The Setup page. Buffer-size settings range from 1024 down to 64 samples.The Pro Tools Mbox's audio quality appears up to scratch in other respects, too, and easily good enough to compete with rivals in the same sort of price range. It reportedly uses the same Cirrus Logic converters as Apogee's Duet and Ensemble, and while I haven't tried either of those interfaces, it would surprise me if there was a huge gulf in sound quality between them and the Mbox 3.

All In All

Having tried the Pro Tools Mbox both with Pro Tools 9 and with Cubase, I think Avid have done pretty well in meeting the self‑imposed challenge of creating an interface that can stand on its own two feet in the wider market. There's little about it that's revolutionary, but it's a good‑sounding, well‑built interface with neat control-panel software and a few nice touches. Many singers will welcome the addition of monitoring reverb, while the Mono button is is a real boon (given how difficult most DAWs make it to audition the main outputs in mono!). And although Pro Tools 9 users now have the option of looking further afield, the Mbox 3 offers tighter integration with the software than third‑party devices, plus a versatile one‑button remote, and has to be a pretty strong contender if you're in the market for a good‑quality desktop interface.  


The market for compact desktop interfaces with a couple of preamps is highly competitive, and there are numerous rivals offering similar feature sets. Focusrite's Saffire Pro 24 DSP is one of rather fewer that can match the Mbox's ability to supply DSP effects during recording. RME's Babyface is another, and packs a surprising amount of I/O into its slimline case. For those who prefer the more basic monitoring approach of the original Mbox, and don't need digital I/O, Mackie's Onyx Blackjack and Steinberg's CI2 are affordable options. Apogee's stylish Duet is, likewise, slimmer in feature terms than the Mbox, but will be an attractive alternative for Mac users.

The Other New Mboxes

There are three products in the revamped Mbox range. The Pro Tools Mbox reviewed in the main text sits between the Pro Tools Mbox Mini and the Pro Tools Mbox Pro. The Mini seems to be a USB 1.1 device, meaning that it is restricted to 48kHz sample rates and below, and is strictly a two‑in/two‑out affair. It has no digital I/O, a single mic preamp on a 'combi' socket that can also accommodate a line input, plus a two more jack inputs, one of which can double as a high‑impedance guitar input. Like earlier Mboxes, zero‑latency monitoring is handled in the analogue domain through a simple Mix control — there's no DSP monitor mixing here. There's also a large volume control for the main stereo outputs, which presumably also controls the level at the single headphone output. The Mbox Mini costs £294$399 in its current form shipping with Pro Tools 8.

The Mbox Pro connects via Firewire rather than USB, and, unlike its smaller siblings, requires mains power. Sample rates up to 192kHz are supported, and there is a total of eight inputs and outputs. Four of the former have mic preamps, and two of these can also accept DI'd electric guitars. Two separate headphone outputs each have their own volume controls. Low‑latency monitoring is handled using built‑in DSP, which can supply monitoring effects, and the Pro also replicates the Mbox's Multi, Dim and Mono buttons. To these it adds some more advanced monitor control features, such as Mute and Alt Source buttons, and the ability to select up to three speaker outputs. There's also S/PDIF, MIDI and word clock I/O. The Mbox Pro presently costs £660$899, again with Pro Tools 8.


  • Solid build quality.
  • Sounds good, with better preamps than previous Mboxes.
  • DSP gives us monitoring reverb and a nice guitar tuner.
  • It has a Mono button!


  • Routing line inputs through the preamps won't suit everyone.
  • Still shipping with the outdated Pro Tools 8 at the moment.


The latest Mbox is a polished and well‑thought‑out product that will appeal to users of Pro Tools and other DAWs alike.


£510 with Pro Tools 8; crossgrade to Pro Tools 9 £215. Prices include VAT.

Avid UK +44 (0)1753 655999.


$679 with Pro Tools 8; crossgrade to Pro Tools 9 $249. Prices are MSRP.

Avid +1 650 731 6300.

Test Spec

  • Mbox package 1.0.19 and firmware 1.0.7.
  • Dell XPS laptop with 2GHz CPU and 4GB RAM, running Windows 7 Home Premium.
  • Tested with Pro Tools 9 and Steinberg Cubase 5.5.2.