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Apogee Symphony I/O

Audio Interface For Mac By Hugh Robjohns
Published September 2011

Apogee claim that their new interface is the result of 25 years of research into digital audio — so we have high expectations for it. Find out whether the Symphony lives up to them.

Apogee Symphony I/O

Apogee Electronics were founded in 1985, right at the dawn of the pro‑audio digital age, and initially made a name for themselves making replacement anti‑alias and reconstruction filter blocks for the leading digital recorders of the day. Back then, the delta‑sigma converters that are ubiquitous today weren't even on the drawing board, and making baseband analogue brick‑wall filters that didn't sound utterly horrendous was a serious challenge. However, the technology quickly moved on, and the demand for third‑party filters disappeared quickly, so Apogee moved into manufacturing complete digital audio converters and, later, master clocks. The company also came up with their unique UV22 dithering algorithm and helped lead the way into noise‑shaped word‑length reduction.

I still own and use a PSX100 two‑channel converter, which I value as much for its clever signal routing and formatting capabilities as its converter quality, which is still quite respectable 12 years on. In more recent years, the Rosetta and X‑Series continued Apogee's reputation for high-quality converters, and the company have also moved progressively away from conventional stand‑alone converters and towards fully‑fledged computer interfaces. However, Apogee took the decision some years ago to restrict their development to only support Apple Mac systems (10.5.8 and above, in fact), much to the frustration of the PC fraternity, including me!


The Symphony I/O's rear panel with a pair of 8 Analog I/O + 8 Optical I/O cards installed.The Symphony I/O's rear panel with a pair of 8 Analog I/O + 8 Optical I/O cards installed.

The subject of this review is the Symphony I/O converter unit and the associated Symphony 64PCIe interface card, which provides the standard gateway to and from a Mac‑based DAW. As I'm not a regular Mac user, Apple kindly provided a loan machine in which I was able to install the 64PCIe card and Maestro software, and configure the system to use the Symphony interface with Apple's Logic Pro DAW. The Symphony system is the official replacement for the AD16X/DA16X and the Rosetta 800 products, which are now withdrawn.

The Symphony can also be used as a direct plug‑in interface with Avid's Pro Tools HD and native systems, and it certainly provides a viable and very flexible alternative to Avid's own hardware interfaces. Since the Symphony system relies on the USB (and Firewire) audio drivers that are part of the Mac OS, and the supplied Maestro control and configuration software will only run on a Mac, there is no facility to fully integrate the Symphony with a PC‑based DAW. I quizzed Apogee about their decision to exclude support of PC systems and was told that by focusing on Mac OS, they feel that they're able to do a much better job. I can see the logic of their argument, but I'm sure it remains a frustration for many and must limit the potential sales market to some extent.

Not all is lost, however, and PC users who really want to use the Symphony converters still can, in a fashion, since the Symphony system can be used in a stand‑alone mode as a straight converter. In this mode, the system is a straightforward multi-channel analogue‑digital and digital‑analogue converter, with either AES3 or ADAT interfacing that can be connected directly to a hardware recorder, or to a PC DAW via a third-party digital I/O interface card. The elephant in the room, though, is that if you require a non‑standard routing configuration you'll still need access to a Mac to set it up! For Pro Tools users, the Pro Tools HD connection mode works with all Pro Tools HD and Native rigs, including PC-based ones.

Apogee say the Symphony is the best-sounding converter they have ever made, which is quite some claim! The converters are apparently based on refined and updated circuitry derived from previous products, but using the latest state‑of‑the‑art converter silicon in an unusual way, which helps to reduce converter latency and improve performance. The analogue stages have also been optimised with very short DC‑coupled signal paths to help maximise clarity and transparency, with ultra‑low distortion and minimal phase shifts. Naturally, the company's C777 clock technology (now further enhanced, too!) has also been employed.


The System Setup page of the Symphony's Maestro 2 control application. The System Setup page of the Symphony's Maestro 2 control application.

The Symphony base unit is a very attractively styled, 2U, rackmounting box, with 16 bright, 10‑segment bar‑graph meters arrayed across the centre portion of the front panel. There are also two multi‑function rotary encoders, both with 'over‑press' switch actions, a pair of independently controlled headphone sockets, and a power on‑off button. A central numerical LED display makes the selected sample rate very obvious, and various text labels illuminate to indicate precisely what is being shown on the meters (either input or output signals from the analogue or digital ports), while an OLED display at the bottom denotes system status and the various operational modes. These last are configured using a system Apogee call AIM, or Audio Interface Modes, via one of the front‑panel encoder knobs.

There are currently four Audio Interface modes. The first, and probably the mode the majority of users would employ, is called Symphony and uses the Symphony 64PCIe card to pass audio and control data to and from a Mac computer. The second mode is the Pro Tools HD mode, which reconfigures the base unit's data port to work in conjunction with a Pro Tools HD card. The Stand‑alone mode does what it says — sets the unit into a static condition, allowing it to serve as a basic A‑D and D‑A converter, for use with applications like Pro Tools LE or M‑Powered, or a PC‑based DAW with a third party digital I/O card. The last and newest operating mode is the USM mode, which transfers audio and control data via the USB port, using the native Mac drivers.

The idea of these four different AIMs is to optimise the Symphony configuration for each type of interface connection with specific DAW setups, like Logic via the PCIe card, or Pro Tools via an HD card, or any Core Audio‑compatible application, such as Digital Performer or Cubase, via the USB interface. All the configuration settings are stored independently for each mode, so that I/O calibration levels, signal routing and so on can be recalled instantly when switching between different systems and configurations.

The Maestro 2 software's input page. The Maestro 2 software's input page. The rear panel of the Symphony base unit has two PC32 multi‑pin connectors, one of which is normally used to connect (using the supplied cable) to a Symphony 64 PCIe card or a Pro Tools HD card. The second socket enables another Symphony unit to be daisy‑chained with the first. Similarly, a second socket on the 64PCIe card allows a third (and fourth) base unit to be connected to the system. There is also a USB port which allows 16 channels at up to 96kHz sample rates to be streamed bi‑directionally with a Mac, and when used with Logic Studio the overall latency is claimed to be below 1.8ms. There is no Firewire interface on the Symphony base unit, and none planned, but there is an Ethernet socket, although this has not yet been activated in the firmware. Comprehensive word clock in and out (both with through sockets) is provided, along with the usual universal-voltage mains inlet IEC socket (90‑240VAC). Although the Symphony base unit is fan‑cooled, the fan speed is temperature‑controlled and, after the initial power‑up frenzy at full speed for a few seconds, it ran completely inaudibly during the whole of the review period!

At the left of the rear panel are two large I/O module slots to cater for a wide range of I/O requirements, providing eight, 16, 24 or 32 channels of analogue and digital I/O. An eight-channel mic preamp module is due to be released imminently, too, using the proven preamp circuitry from Apogee's excellent Trak 2 unit. There are currently four standard interface modules (the mic preamp will be the fifth), which comprise two eight-channel cards and two 16-channel cards. The two eight-channel cards both provide eight analogue line inputs and outputs (all via two D‑sub sockets wired to the usual Tascam format), supplemented with either four stereo channels of AES3 I/O (on another D‑sub) or dual ADAT lightpipe I/O (with SMUX support for the higher sample rates). Both modules are also equipped with a single stereo channel of coaxial S/PDIF I/O on RCA phono sockets.

The two 16‑channel cards provide either 16 channels of analogue line inputs with 16 ADAT outputs, or 16 analogue line outputs with 16 ADAT inputs, and both have a stereo S/PDIF co‑ax input and output on RCA phono sockets as well. These eight- and 16-channel cards can be mixed and matched to suit the specific I/O requirements of each installation. By default, the first two analogue outputs of the first I/O module are configured as a stereo monitor loudspeaker feed, and 20dB of attenuation is automatically inserted to protect the monitor speakers and the users' ears! This signal allocation and the protective attenuation can be removed, if necessary, of course, but for most installations it saves having to create custom monitoring configurations.

The shortly‑to‑be‑released mic-input card will operate in conjunction with one of the eight-channel analogue I/O cards, essentially inserting Trak 2‑style mic preamps (with up to 85dB gain) into each of the corresponding line inputs. The first four channels are equipped with instrument DI inputs too. This mic preamp module will also provide eight fully balanced insert points to accommodate analogue outboard.

The technical specifications for these converter modules are impressive, and I was able to confirm the published specifications in my own tests using an Audio Precision test set. The A‑D section's THD+N figure scores ‑113dB with a +20dBu input — and if that doesn't sound particularly special, think again, because that's an unweighted figure. Most converters struggle to reach that even with a weighted measurement! I also measured an AES17 dynamic range figure of a shade under 115dB, rising to 120dB when A‑weighted. These indicate impressive technical performance. The D‑A section is equally exciting, with a THD+N figure of a very healthy ‑117dB (again, this is an unweighted figure with a +20dBu output). The D‑A dynamic range (A‑weighted, this time) scores a remarkable 129dB. The maximum analogue input and output levels are +24dBu (when set to a nominal +4dBu operating level), so these performance figures were obtained with a small headroom margin remaining.

As has become traditional with Apogee converters, the Symphony system has a soft‑limit facility that can be set through the Maestro GUI (see below) to provide protective limiting at ‑2dBFS or ‑4dBFS, or to provide 'soft‑saturation' or 'soft‑crushing' modes. Personally, I prefer to leave these modes switched off and work with a practical headroom margin instead, but for those who still like to exercise the whole of the digital meter scale when tracking, they provide an invaluable safety net. Indeed, the soft saturate and soft crush modes can be used creatively on percussive sources to provide a similar transient-crushing treatment to analogue tape.

Maestro 2 Software

The five currently available I/O modules. The five currently available I/O modules.

Every aspect of the Symphony interface is configurable through a control application called Maestro 2 (see screens overleaf), which allows the user to configure the clocking arrangements and sample rates, I/O routing and metering, mic preamp gains, loudspeaker output and headphone levels, and input and output level calibrations, amongst other things. This Maestro software isn't compatible with the Duet 2 or other Apogee hardware like the AD16X and DA16X or Rosetta Series (which still require Maestro 1). As an alternative to the main, multi‑tab Maestro control window, a minimised toolbar view is also available, which shows the system status, and provides volume controls and buttons to mute the outputs and clear the metered Over indications.

This toolbar mode is very handy and can be arranged for convenient access on the Mac screen without cluttering up or obscuring the DAW control and display windows. In practice, once the Symphony system is configured, there is no need to consult the main Maestro window at all, but having access to the toolbar version is important if you're using the Symphony's loudspeaker and headphone outputs.

Symphony In Use

Installing and configuring the 64PCIe card and Maestro software took about 10 minutes and was completely trouble‑free and straightforward. The Symphony I/O was found instantly and I was able to configure the clocking, audio routing and I/O calibrations completely intuitively, without needing to read the user instructions (which are included as a PDF file with the latest Maestro 2 software download). Once up and running, all of the I/O ports were available in Logic's channel routing, and getting signals in and out of the system from then on was trivially simple.

Listening critically to the Symphony as a converter, I was very impressed with the enormous dynamic range and the very clean and benign system noise floor. Whereas most previous Apogee converters have bestowed a certain character to the sound, I would say the Symphony is the most neutral and transparent model the company have produced. Converters demonstrate the laws of diminishing returns better than virtually every other pro‑audio product category, but even at the asking price, the Symphony could be a great worry to some of the quality converter manufacturers. This is a seriously good performer in its own right — and that's before you add in the value of all the other features and connectivity provided here.


The Symphony system is still something of a work in progress, but this is a good thing, as the design is sufficiently open‑ended to be able to accommodate any future interface standard — such as the much heralded Thunderbolt, for example — quite easily, and this future‑proof aspect of the unit is one of its major selling points. The Apogee Electronics web site has the published plans for the first four developmental stages of the Symphony's progression, and it is impressive to note that three of those have already been completed (in August and October 2010 and April 2011). The fourth stage is already in a public beta-test phase at the time of writing. Early Symphony adopters have been pleased to see the capabilities of their systems increase and expand as each new development phase has been completed, and the fourth stage brings yet more facilities, including support for the mic preamp interface module (and remote control of it from Pro Tools), along with activation of the USB audio interface mode. It also provides support for up to four Symphony I/O units in the Pro Tools HD audio interface mode.

Further enhancements in the wings but still to be implemented include expanded hardware routing facilities, extended legacy support for X‑Series and Rosetta converters, and the introduction of UV22HR noise‑shaped word-length reduction. Full Eucon control surface support is also planned, along with activation of the Ethernet interface and support for MADI interfaces.

So what we have here is a very flexible and quite scalable audio interface that should enjoy excellent longevity because of its modular I/O structure and open architecture — so it's not likely to be rendered obsolete in a hurry. With the versatile I/O complements, comprehensive software control, and the ability to connect directly to computers via USB, 64PCIe interface, or Pro Tools HD interface, the Symphony is a very attractive system. The quality of the audio signal path lives up to Apogee's claims — this is a very nice and extremely transparent-sounding converter, without the subtle colourations that have been associated with earlier Apogee designs. If I owned a Mac, this would be a very serious contender for the audio interface of choice. Nice one, Apogee!  


Because of the Symphony I/O's freely configurable nature, it's impossible to nominate direct alternatives in any meaningful way. However, there are systems available from the likes of RME, Lynx, SSL and Prism Sound (among others) that can be considered broadly similar, and which are also, unlike the Symphony I/O, PC‑compatible.


  • Extremely versatile analogue and digital I/O options.
  • Compatible with Pro Tools HD and Native systems.
  • Flexible computer interfacing via USB and PCIe or Express cards.
  • The best-sounding and most transparent Apogee converters to date.
  • Open architecture and modularity ensure service longevity.


  • No direct support for, or compatibility with, PC‑based DAWs.
  • No Firewire connectivity.


An impressively versatile audio interface with the best-sounding converters Apogee have produced to date. Compatible with Pro Tools and any Mac‑based DAW, and connected either via a PCIe card or USB, the Symphony is highly configurable in terms of its analogue and digital I/O, and a mic preamp card is about to be launched to complement the system further.


Symphony base unit £1596; Option cards £1887.60 each; Symphony 64 PCIe card £858. Prices include VAT.

Sonic Distribution Ltd +44 (0)845 500 2 500.


Symphony base unit $1695, Option cards $1995 each, Symphony 64 PCIe card $995.

Apogee Electronics +1 310 584 9394.