Apogee Electronics Duet 2 USB Audio Interface ReviewA two-input/four-output converter for high-quality audio capture. 1/17/2013 7:36 AM Eastern
Apogee Electronics Duet 2 USB Audio Interface Review
Jan 17, 2013 12:36 PM, Reviewer: John McJunkin
A two-input/four-output converter for high-quality audio capture.
Apogee has long been known for its high-quality analog-to-digital and digital-to-analog converters, with products used in studios since the late 1980s. The company’s line has expanded to include multi-track systems, high-precision clocks, and consumer products to bring high quality to a broader market. A collaboration with Apple has produced some exceptional hardware, including the Duet, a FireWire-based two-input/two-output interface well-known for its sandwich-sized enclosure and large multi-purpose control knob. Despite the Duet’s primary drawback—unbalanced outputs, it became popular and sounded very good.
High-quality converters like the Duet are useful to contractors when pristine audio is necessary. There are essentially three levels of quality available when introducing computer-originating audio into the mix. At worst, most computers have a 1/8in. output jack fed by a cheap sound circuit on the computer motherboard, delivering very poor-to-passable quality sound. The next level comes from decent third-party sound cards connected to a PCI slot, or externally via USB or FireWire. This typically delivers quality ranging from moderate to very good. If a client insists on truly pristine audio, however, a high-end solution is in order, and there are PCI, USB, and FireWire interfaces with extremely stable clocks and exceptional converters. The original Duet and new Duet 2 represent this type of product.
The Apogee Duet 2 measures roughly 6in. long, 4in. wide, and just shy of 1in. in height (excluding its very large primary data input encoding knob, which protrudes an additional 3/8in. or so above the main enclosure). The housing is primarily aluminum, features a large rubber underside pad, and exhibits some pretty substantial heft in terms of weight—I’d guess a bit more than a pound. There is a 1/4in. headphone jack on the right side of the enclosure, and on the other end is a DC power inlet, USB port, and Apogee’s proprietary I/O connector into which plugs a breakout connector—a cable that fans out into two stereo pairs, balanced 1/4in. TRS jacks and balanced combi 1/4in./XLR connectors. With the Duet 2, Apogee addressed the complaint pertaining to its original Duet by deploying balanced outputs.
Another quibble common to both Duet versions is the decision to employ a breakout cable scheme rather than including the I/O connectors inside the unit’s housing. To do so would certainly result in a larger desktop footprint, and likely increase the retail price of the interface. Apogee considered input from Duet users and reached a compromise with them: The breakout cable of the Duet 2 can be connected with a single cable to an external enclosure known as the “Duet Breakout box” with the I/O connections sturdily housed therein. This facilitates a much cleaner “installation” (the unit is intended as a semi-portable desktop solution), with just the single cable visible. I also see Apogee’s wisdom here, however. If all the I/O were included in the main enclosure, many cables would clutter the desktop environment. A single, neat cable is vastly preferable in my opinion.
Aside from the Duet2’s famous aluminum knob, there are other controls and displays on top of its enclosure. Specifically, the glossy black plastic surface atop the housing is touch sensitive, with two buttons that can be assigned via software to various tasks, including the muting, dimming, or summing to mono of main outputs, headphone output, or both. The buttons can also be programmed to toggle through the various available sources that can feed the headphone output, and also to clear the meters. The Duet 2’s display is much more sophisticated than the multi-segment LED meters featured by the original Duet. A bright and clear OLED display shows levels for both input channels and stereo levels for both main and headphone outputs. It also shows an information-rich circular display of input and output settings as dialed in by the large knob. The knob is also a momentary pushbutton that toggles through four types of level controls: input channels one and two, and main and headphone outputs, which are distinct of each other as a result of Apogee once again taking customer input into consideration. I’m always happy to see manufacturers respond to their users.
The Duet 2 is an Apple-only interface, and Apogee has developed a Mac application called “Maestro” that facilitates configuration and control of the interface from the computer. The app can address multiple interfaces, and presents a graphical user interface that reflects the physical interface. There are controls for input levels, including mic, instrument, and two line-level settings (+4dBu and -10dBu). Metering shows input levels, and the two channels can be grouped together, which gangs input level together but leaves polarity and phantom power toggling independent per channel. Grouping also works for instrument level, but obviously eliminates phantom power. One minor disappointment here: There’s no capacity for renaming the inputs in the graphical user interface or saving snapshots. This would be easy to implement and a very useful tool.
The output page controls the unit’s output levels. The main outputs can be toggled between +4dBu and -10dBu, and there are pushbuttons to dim, mute, or sum-to-mono both headphones and main outputs. Also, drop-down menus determine which software output pair is sent to headphones and to main outputs, including the unit’s internal mixer output. The mixer can blend live mic or line inputs with playback from the computer for overdubbing purposes. A device setting button configures the physical interface’s two touchscreen buttons, and a system setup button enables determination of sample rate, meter attributes, and which hardware output is affected by the Macintosh keyboard volume control. A large button in the upper left hand corner of the graphical user interface allows the user to clear the meters’ red peak LEDs. Maestro also controls one very impressive attribute of the interface: Apogee’s famous soft limiters. These come in very handy when recording widely dynamic and inconsistent voices in presentation, conference, or other business-oriented applications.
Super high-end converters with ultra-stable clocks can deliver pristine fidelity, but the Duet 2 gets you most of the way there. In order to render that slightly higher quality audible would require loudspeakers of virtually studio-monitor fidelity. And even then, the distinction in quality would likely be lost on most of the audience. There may be rare applications that require this level of quality, but the Duet2 easily handles the other 99 percent. The Apogee mic preamps are very quiet, very transparent, and sound great. The soft limiters help tame widely dynamic signals, contributing to the capture of a good recording. There’s a night-and-day difference between a computer’s 1/8in. audio output and the Duet 2, and other inexpensive PCI or external interfaces just don’t hold a candle to the Apogee unit. The interface makes a big enough difference to be well worth consideration.
Pros: High-quality A/D, D/A conversion and mic preamps; excellent control surface
Cons: No capacity to rename inputs or save a snapshot in Maestro
Applications: Pristine quality computer audio output, very high fidelity recording
EIN: 128dB (un-weighted) @60dB, 150Ω output
Max input level: +20dBu
Input impedance: 3kΩ
Max input level: 14dBu
Input impedance: >2MΩ
Max input level: (+4dBu ref): +20dBu
Max input level: (+10dBV ref): +6dBV
Input impedance: 5kΩ
Freq. resp. 20Hz-20kHz: >±0.2dB (@44.1kHz)
Rel. THD + N: -106dB (@96kHz)
Dyn. range: 114dB (A-weighted)
Max output level (+4dBu ref): +20dBu
Max output level (-10dBV ref): +6dBV
Line output impedance: 90Ω
Max output level headphones: 19dBu
HPH output impedance: 30Ω
Freq. resp. 20Hz-20kHz: >±0.05dB (@44.1kHz)
Rel. THD + N: -113dB (@96kHz)
Dyn. range: 123dB (A-weighted)
John McJunkin is the principal of Avalon Podcasting in Chandler, Ariz., and produces and co-hosts a top-rated morning radio talk show in Phoenix. He has consulted in the development of studios and installations and provides high-quality podcast and voice production services.