Apogee Symphony Desktop – flagship two-channel interface with hardware DSP

Maxim Liadov

American company Apogee needs little introduction. The bestselling two-channel Apogee Duet and the more advanced Apogee Quartet are established studio products with advanced electronics and excellent sound. Other familiar features are expensive Apple-style design and a colour display on top.

The Symphony Desktop inherits these strengths, improves the electronics further and adds Apogee FX hardware processing. The official video explains more:

Its screen interface comes from the expensive Symphony I/O models. Electronics and specifications are similarly high level.

FX Rack plug-ins run on the internal DSP, as on Apogee Element and Ensemble Thunderbolt. Their controls appear directly on the touchscreen.

The Symphony Desktop includes licences for two plug-ins and a discount on the others. They can run in real time on hardware or entirely on the computer CPU inside a DAW. Switching between hardware and software processing is quick within the DAW. Apogee calls DualPath unique. Normally, users choose dry direct monitoring or software monitoring with CPU-processing latency. DualPath provides real-time hardware processing, then the same processing during mixing, even on a computer without the Symphony Desktop. Native plug-in licences use iLok.

DAW integration currently works only on Apple computers; Windows support is planned. Windows already has internal hardware processing and separate native plug-ins. Hardware plug-in choice is still small compared with UAD or ProTools HD, but that is not the main goal. Most studio work uses native plug-ins because they are available in greater variety. Hardware often supplies EQ and reverb mainly to make performer monitoring closer to the final sound. Keeping that processing in the mix is a useful extra.

Apogee Symphony Desktop specifications

General specifications

• 2 Advanced Stepped Gain microphone preamps
• Apogee Alloy preamp emulation, analogue plus DSP
• FET guitar input with tube-like response
• 2 balanced TRS outputs
• 2 assignable headphone outputs, 1/4-inch and 1/8-inch
• Optical ADAT I/O with S/PDIF support
• 10 input × 14 output channels simultaneously
• USB 2.0 through USB Type-C
• Hardware DSP supporting Apogee FX plug-ins

Compatibility

• macOS 10.13 High Sierra or later
• macOS Big Sur and M1 processor support
• iOS/iPad pro: iOS 13
• PC: Windows 10 Anniversary Update or later

Included plug-ins

• Clearmountain's Spaces: macOS and Windows 10, native VST/AAX only
• Symphony ECS Channel Strip: macOS and Windows 10, VST/AAX and hardware DSP

Included preamp emulations

• AP-66 — British Solid State
• AP-57 — 50s American Tube

Line input

• Dynamic range: 123 dBA
• THD+N: -113 dB
• Frequency-response variation, 10 Hz–20 kHz: >±0.2 dB
• Input sensitivity, +4 dBu preset: +20 dBu
• Input sensitivity, -10 dBV preset: +6 dBV

Preamps

• Gain: 75 dB
• 48 V phantom power
• Soft Limit soft-threshold limiters
• Polarity inversion
• EIN: 129 dB unweighted at 60 dB gain, 150 ohms
• Hi-Z input sensitivity: 14 dBu
• Hi-Z input impedance: 220 kohms / 470 kohms / >20 Mohms

Line output

• Dynamic range: 129 dBA
• THD+N: -114 dB
• Frequency-response variation, 10 Hz–20 kHz: >±0.05 dB
• Level at 0 dBFS, +4 dBu preset: +20 dBu
• Level at 0 dBFS, -10 dBV preset: +6 dBV

Headphone output

• Dynamic range: 128 dBA
• THD+N: -111 dB into 600 ohms
• Power into 30 ohms: 520 mW
• Power into 600 ohms: 90 mW

Recording and playback specifications are very high, and our measurements fully confirm them. These are real input/output results from a production unit under practical conditions, not theoretical converter-chip ratings.

Electronics and measured performance take a significant step forward. Symphony Desktop even measures 1 dB better than the flagship Symphony I/O MKII, an excellent result.

Current drivers and firmware provide only basic functions. Symphony ECS Channel Strip is controlled from the hardware touchscreen. A full macOS and Windows 10 panel is planned for driver version 1.2.

The same controls are already available on the screen, but spread across different pages. The panel should make operation more convenient.

The control principle is simple. Select a parameter on the touchscreen, such as input-one gain, then turn the large knob for fine adjustment. This is much better than touchscreen-only operation, especially for output volume. A physical knob can be found by touch while attention stays on creative work.

Two headphone outputs are fully independent, with separate signal assignments and volume. One is on the front, the other on the back. The front also has the guitar input.

 

The rear has combo XLR/TRS inputs, balanced TRS outputs, ADAT, a USB port for a MIDI keyboard useful with iPad, USB-C for a computer and a socket for the 30 W external adapter.

Two thick cast-metal halves form a strong case. Construction feels careful and professionally engineered.

USB uses an XMOS XU216 controller. We could not identify the DSP because it sits in a difficult-to-reach shielded area to avoid affecting analogue circuits.

There are two separate DACs for line and headphone outputs.

One is ES9016S, as in Duet and Quartet. The new second DAC is the two-channel ES9028Q2M, providing 129 dBA line-output dynamic range and better sound than smaller Apogee interfaces. This approaches Symphony I/O quality, with fewer channels and no external synchronization.

A particularly interesting choice is a 4-channel AKM AK5574 ADC in dual-mono mode, providing 123 dBA line-input dynamic range.

THAT 5171 controllers provide digital control of analogue gain through high-quality, low-noise TI OPA1612A op-amps: 0.000015% THD+N and 1.1 nV/Hz^1/2 noise.

For technically experienced readers: OPA1612A is not a typo. Its standard WSON-8 package marking is OVII. The 551 numbers mean something else to the manufacturer. OPA551 was not made in that package and would not belong in this preamp circuit.

INA1620 current buffers drive headphones. These outputs are significantly more powerful and better than those on smaller Apogee models.

ASIO diagnostics

The 192 kHz limit relates to USB 2.0 bandwidth: the current UAC 2.0 configuration carries the highest formats only with two channels. Multichannel 768 kHz operation would need a faster connection.

RightMark Audio Analyzer test report

Device under test	[ASIO] Apogee USB ASIO Driver
Operating mode	24-bit, 44 kHz
Signal path	External loopback (line-out — line-in)
RMAA version	6.4.5 PRO
20 Hz–20 kHz filter	YES
Signal normalization	YES
Level change	0.0 dB / 0.0 dB
MONO mode	NO
Calibration signal frequency, Hz	1000
Polarity	Correct/correct

Frequency response variation (40 Hz–15 kHz), dB	+0.01, -0.06	Excellent
Noise level, dB(A)	-123.3	Excellent
Dynamic range, dB(A)	122.9	Excellent
Harmonic distortion, %	0.00025	Excellent
Harmonic distortion + noise, dB(A)	-108.8	Excellent
Intermodulation distortion + noise, %	0.00061	Excellent
Stereo crosstalk, dB	-123.1	Excellent
Intermodulation at 10 kHz, %	0.00042	Excellent
Overall rating		Excellent

Detailed 24-bit/44 kHz measurement results

Measurements confirm the high, record-level Apogee specifications. There is no interference or other issue. Output-only results would be higher, requiring dedicated measurement equipment. A practical benefit is the absence of noise even after large digital gain changes.

We were especially interested in the preamps and Apogee Alloy DSP emulation. Recording a Neumann TLM102 produced some of the best quality we have encountered. Enabling preamp emulation adds about 2 dB of level and a little tonal processing.

The clean preamps already sound excellent, so emulation is optional, depending on taste and creative needs. For example, RME's two-channel flagship interfaces, the ADI-2 PRO and ADI-2 DAC do not have this processing. Their sound instead aims for complete neutrality, useful in many situations.

Symphony Desktop output quality is high through both headphones and monitors. We used three-way active studio monitors, the ADAM S3H in an acoustically treated room. This is high-level studio sound, with all frequency ranges clearly audible. Mixes should translate well to today's common DACs using ESS converters.

Conclusions

The Symphony Desktop is a true flagship two-channel interface with interesting hardware DSP. Its original ideas stand out among similar interfaces and expand creative tools in a commercial studio. The main limit is just 2 preamp and line-output channels. Parts can be overdubbed, a standard studio method; multiple takes are common anyway. The complex design did not include every planned function at launch, and useful additions are expected soon. We hope these developments eventually reach lower-priced models after early buyers fund the initial work. We look forward to more interesting Apogee products.

Note. This is an adapted machine translation into English. It follows the “In simple terms” approach. Read the original article at https://prosound.ixbt.com/interfaces/apogee-symphony-desktop.shtml.