You are here

Apogee Duet 3

USB Audio Interface By Sam Inglis
Published April 2022

Apogee Duet 3 USB audio interface

Apogee’s long‑serving desktop audio interface gets a thorough makeover.

When desktop audio interfaces first appeared, they were usually marketed as budget options for hobbyists. Apogee overturned that perception with the Duet, a stereo interface that majored on sleek design and superior sound quality. The original Firewire version was superseded by the USB Duet 2 in 2012, and so successful has this been that it’s only now being retired in favour of a new Duet 3.

Third Movement

The Duet’s positioning as a premium product has always depended in part on its attractive industrial design, and the Duet 3 has been reinvented on cutting‑edge aesthetic principles. The aluminium body is topped by a sheet of obsidian‑like black toughened glass, beneath which various LEDs are invisible when not illuminated. The only moving part is a large rotary control, which sheds a mysterious purple glow from its nether regions. The overall effect is striking and very much of a piece with recent Apple consumer products, or possibly the interior of a spaceship.

The Duet 3 still connects to the host computer or iOS device using USB, but employs the now‑current Type C connector rather than the older Type A. It no longer comes with an external power supply; instead, a second Type C socket is built in to allow powering from a dedicated USB source if your laptop can’t provide the necessary juice, or if you want to use it with an iPhone. Apogee describe the Duet 3 as a two‑in, four‑out interface; in other words, it’s a stereo device where the headphone output can be addressed independently from the main output.

As before, the only conventional audio connector actually built into the Duet 3 is a single mini‑jack headphone socket. There are two ways of accessing the main inputs and outputs. One is to use the supplied flying cable, which locks securely into a compact multi‑way connector on the back of the interface. The other is to purchase the optional Duet Dock, a plastic desktop chassis that mates with the Duet, rather spoiling its elegant minimalist appearance, and breaks all of its I/O out onto dedicated connectors. Adding the Duet Dock is also the only way to get a full‑sized headphone socket. This mirrors the mini‑jack on the front panel so you can connect two sets of headphones at once, albeit without any control over their relative levels.

A welcome improvement, compared with the Duet 2, is the provision of separate XLR and quarter‑inch sockets for the inputs, both on the flying lead and the Dock. This doesn’t allow you to record more than two sources at once, but does mean you can leave mics plugged in at the same time as guitars. Note, however, that the quarter‑inch sockets are unbalanced and designed for guitar use; if you want to get the best from balanced line‑level sources, you’ll need to connect these to the XLR inputs. I’m not awfully keen on this arrangement, as it makes it possible to apply phantom power to things that shouldn’t receive it, as well as requiring jack‑to‑XLR cables for most synths, which many people won’t have.

The Duet 3 can be connected to instruments, mics and loudspeakers either using the supplied breakout cable or the optional Duet Dock.The Duet 3 can be connected to instruments, mics and loudspeakers either using the supplied breakout cable or the optional Duet Dock.

Controlling Influence

Many desktop interfaces are designed to be used without any form of software control panel, making all of their functionality controllable in hardware, but that’s not the case with the Duet 3. It’s class compliant, so requires no driver on Mac OS, but top‑panel control is restricted to input gain, headphone and main output volume, and mute. Most of its features must therefore be controlled from the attached computer.

All of Apogee’s USB interfaces are now handled by a single package called Apogee Control 2, which detects what interface is attached, invites you to update firmware when necessary, and displays the appropriate control panel. This is clearly laid out and mostly self‑explanatory. It’s also described clearly in the PDF manual, which is lucky, because the Hover Help window does not yet offer any hovering help. Other than that, it ran flawlessly on my Mac; I did not test it on Windows.

Apogee Control 2 makes visible the mixer built into the Duet 3, which is fed by two mono (but linkable) inputs derived from the mic or guitar sockets, and two stereo inputs derived from your DAW’s outputs. The output of this mixer can be routed to the main speaker outs and/or the headphone output; alternatively, if you prefer, these can be set to pick up one of the DAW playback channels directly. The mixer output can also be routed to the DAW software inputs, allowing software‑generated sound to be re‑recorded. Selecting this option brings up a stern but very apposite warning about the possibility of generating feedback loops.

The more you work with this control panel, the more you appreciate the attention to detail that has gone into the design of the Duet 3. For example, the output volume control is mirrored by the Mac OS volume level, so you can adjust it using the volume up/down keys on your Mac, and it’s possible to switch this so that the system volume controls the headphone level while the Duet’s knob adjusts speaker level, or vice versa. Both the headphones and speakers have independent mute, dim and mono controls, and you can even adjust the brightness of the Duet’s LEDs from Apogee Control 2. What is sadly missing in action, however, is the Duet 2’s pair of assignable touch buttons. This means it’s no longer possible to engage the mono or dim options directly from the Duet itself.

Audio quality in general, and mic preamp design in particular, have always been big selling points for Apogee. In line mode, the XLR inputs can be switched between +4dBu and ‑10dBV sensitivity levels, while in mic mode, they provide up to 65dB of gain, adjustable in 1dB steps. This is actually a smaller gain range than was available on the Duet 2, but is still wider than you’ll find on most desktop interfaces, and perfectly adequate for most of the Duet 3’s intended applications. You also get the bonus of a switchable soft limiter, polarity reversal and a link button which allows the gain on the two mic preamps to be ganged whilst preserving any existing offset between them. A further button in the input settings area provides access to what is probably the biggest new development in the Duet 3.

In Print

Ever since Steinberg launched the VST protocol back in 1998, people have been telling me that the days of DSP built into audio interfaces are numbered. Someone forgot to tell the manufacturers, though, because in recent years it has become more rather than less ubiquitous. It’s a major selling point of Apogee’s larger Symphony Desktop, and, in a much more streamlined implementation, is on tap in the Duet 3 too.

There are various ways in which onboard DSP can be presented to the user. It can be normally be placed in the monitor path, allowing performers to hear a low‑latency foldback signal processed with compression and so on whilst the engineer tracks an unprocessed signal. Additionally, it can sometimes be made available to DAW software to run plug‑ins at mixdown. In the Duet 3, however, the onboard DSP is referred to as Print FX, and as that name suggests, it can be used only in the record path. In other words, if you activate the DSP, it will always be processing the signal that’s going to disk as well as that going to the performer’s headphones.

Apogee Control 2 and the Symphony ECS Channel Strip.Apogee Control 2 and the Symphony ECS Channel Strip.

Like many other manufacturers, Apogee package their DSP functions in a plug‑in‑like interface. However, whereas the Symphony Desktop offers a choice of half a dozen plug‑ins, only one is available here. Clicking on the Print FX button in the Apogee Control 2 interface opens a cheerful grey window with purple controls, which is described as the Symphony ECS Channel Strip. This was developed in association with legendary mix engineer Bob Clearmountain, and he was responsible for the 25 or so presets that are supplied. It occupies an interesting middle ground between the sort of utilitarian signal conditioning that you find on most digital mixers, and the colourful vintage‑style processing we effect from companies like UA. A variable high‑pass filter is bolted onto an EQ section that is clearly designed for broad‑brush tone shaping in the Pultec vein, while the compressor offers only ratio and threshold controls, but with the option to blend in the dry signal to taste. The order of the two sections can be switched, and the high‑pass filter can also be switched into the compressor side‑chain. Finally, there’s an analogue‑style Drive control as well as a standard output level control.

It’s not possible to access the Duet 3’s DSP directly from within your DAW, so you can’t use the DSP version of Symphony ECS Channel Strip as if it were a native plug‑in, UA‑style. However, if you like the sound, but not the thought of tracking through it and having it printed on all your recordings, you can invest in a native version which is available in all the usual plug‑in formats and comes with the same presets. This isn’t particularly expensive as plug‑ins go, but it is a cost option, and I can imagine some Duet 3 purchasers feeling resentful at having to pay to get the native version of something they already own in DSP. In practice, though, I actually rather liked the way Apogee’s DSP implementation forces you to commit to a sound at the recording stage. As you’d expect, Bob Clearmountain’s presets are very usable, and the generally streamlined control set makes it easy to home in on the settings you want.

As a bus‑powered desktop interface with built‑in DSP, the obvious rivals for the Duet 3 are UA’s Apollo Solo and Antelope Audio’s Zen Go Synergy Core. Those products both give you the option to track through an almost endless variety of simulated guitar amps, mic preamps and vintage studio hardware, as well as letting you record dry and monitor wet. The DSP capabilities of the Duet 3, though certainly worthwhile, are obviously rather modest in comparison. If you’re a podcaster or voiceover artist who just wants a good ‘set and forget’ vocal treatment, Symphony ECS Channel Strip will do the job nicely. If you want to explore the outer reaches of guitar tone or authentic emulations of vintage studio hardware, it won’t get you there.

If you’re looking for a portable interface with the kind of sound quality that’s usually available only in mains‑powered units, options are relatively limited, but the Duet 3 is certainly one.

In Harmony

Apogee interfaces have always been premium products, and the Duet 3 is no exception. That price premium buys you some tangible benefits. One I haven’t mentioned so far is the supplied carry case, which safely houses the Duet and its breakout cable in a tough, no‑nonsense padded environment. Another is the sound quality. The Duet 2 was already impressing in this respect 10 years ago, and the new model improves on nearly all its specifications. Dynamic range on the inputs and outputs is now 119dB and 124dB respectively, and the Duet 3 features a new “zero Ohm” headphone amp that can deliver much higher output levels than most bus‑powered designs. If you’re looking for a portable interface with the kind of sound quality that’s usually available only in mains‑powered units, options are relatively limited, but the Duet 3 is certainly one. It’s also uniquely and distinctively stylish, at least until you add the Dock.

Apogee Duet 3

However, there are also a few respects in which the Duet 3 is lacking compared with its predecessor. I’ve already mentioned the narrower gain range and the loss of the touch buttons, which makes the Duet 3 less powerful as a hands‑on monitor controller, and another limitation concerns iOS compatibility. At present, the Duet 3 will work with iOS devices, but the only control available is that offered by the encoder. Settings that, on a computer, are only available in Apogee Control 2 cannot yet be adjusted from an iOS device. Until the promised control app is released, this probably makes the Duet 3 usable as a playback device but of limited value for recording to an iPad or similar.

I also feel that the minimalism of the Duet’s physical design undermines its intuitiveness in some small ways. For example, the purple LEDs around the wheel do double duty, showing you which parameter is currently assigned to the wheel and flashing if something is muted, and this can make it hard to see what’s going on at a glance. There are some important settings that are visible in Apogee Control 2 but not at all on the unit itself, yet conversely there’s no visual indication of controller assignment within Apogee Control 2. In use, this means it’s quite often necessary both to glance at the unit itself and to tab away from your DAW to Apogee Control, which doesn’t always make for a seamless user experience. The Duet 3 also has an unwelcome tendency to spit out thumps and splats when you shut down the computer.

All things considered, though, these are minor wrinkles, and some at least will be dealt with in future updates. In the bigger picture, it’s always been classy looks and exemplary sound quality that have kept the Duet in the best‑seller lists — and the Duet 3 is the best‑looking and best‑sounding Duet yet.


  • Elegant, minimalist design.
  • Excellent sound quality.
  • Good‑quality carry case supplied for portable use.
  • Optional Duet Dock as an alternative to the flying cables.
  • Built‑in DSP allows you to record with EQ and compression.


  • Limited iOS support at present.
  • Loses the Duet 2’s touch buttons.
  • Native version of the Symphony ECS Channel Strip plug‑in is a cost option.
  • Balanced line inputs on XLRs only.
  • DSP can only be used in the record path.


Apogee’s Duet 3 makes a visual and sonic statement. It may not be the most affordable desktop interface, but it’s undoubtedly the most stylish!


Duet 3 £649, Duet Dock £149, native Symphony ECS Channel Strip plug‑in $49 when bought with Duet 3. Prices include VAT.

Sound Technology +44 (0)1462 480000.

$649; Duet Dock $179; native Symphony ECS Channel Strip plug‑in $49 when bought with Duet 3.