Audient iD48 interface review - A genius ID?

The ID48 is an audio interface we’ve been waiting for. At last, Audient completes its iD line with a top-of-the-range unit, signalling the British brand’s move to another echelon in audio interface design. And deservedly so, for Audient, whose high-quality consoles we won’t go into here, has also established itself year after year as a major reference in the world of pro and semi-pro audio. Known for sturdy build-quality and competitive price/performance ratio, Audient interfaces, including the  iD14, iD24 and iD44, have garnered positive reviews from us thanks to their sonic transparency and meticulous construction.

Today, Audient returns with the iD48, a USB-C interface designed to meet the more extensive needs of larger studios. Indeed, this new model aims to complete the range with a more generous input/output proposition and enhanced functionality, all in a classic 19-inch rackmount format. Let’s see what it’s got up its sleeve.

Product description: connections, ergonomics, usage and more

As usual, before commenting on the good and not-so-good aspects of the device, let’s proceed to an objective description of its functions:

On the front panel (from left to right): 

• Two instrument inputs (6.35 mm (1/4-inch) jack —  for channels 1 and 2.
• Gain settings (via knobs) for each input channel (1 to 8), with a simple level display: white if OK, orange when approaching the limit, and red when it exceeds it.
• Eight +48 V (phantom power) selectors, one per input, in the form of a lever switch, with, just below it, a backlit red display that signals operation.
• Three other backlit displays, this time white: ADC (signals that preamps are bypassed), HPF (high-pass filter) and PAD (attenuator).
• A multisection LED VU meter and a large multifunction rotary encoder.
• Four additional control buttons: ALT (alternative monitor listening), TB (talkback), F1 and F2 (assignable functions).
• Two headphone outputs — 6.35 mm jack (1/4-inch) — with independent volume knobs.

On the rear panel (from left to right): 

• Four ADAT optical ports, divided as follows: ADAT OUT 1 and 2, ADAT IN 1 and 2.
• Word Clock connectivity with one input and one output (on BNC jacks).
• Four outputs for active monitors —6.35 mm (1/4-inch) TRS jacks — with the main outputs (1L / 2R) and those controlled by the front-panel ALT button (3L / 4R).
• Two DB25 connectors: These are perhaps the most notable features of the device. The first offers eight line outputs or possibly eight insert sends, while the second offers eight ADC inputs, i.e., eight inputs directly into the A/D converter, or eight insert returns. We’ll come back to these two connectors shortly.
• Eight mic/line inputs on XLR/6.35 mm (1–4-inch) combo jacks (channels 1 to 8).

Now, let’s go into a bit more detail about some of the things we like, and some that we don’t: 

The construction is remarkably sturdy, featuring high-quality materials and connectors. Ergonomically, the device is well-designed, with well-separated sections on the front panel, and certain mechanical elements, such as lever-operated selectors — a specialty of the iD series — which stand out in the current production of mass-market audio devices and retain their tactile charm. In the same vein, adjusting each gain with a knob (which has good inertia) gives the user a rather pleasant sensation of physical control. On the other hand, the two headphone amplification level controls are a little too close together, making them less practical.

The IO count is quite satisfactory, and the presence of eight insert lines, or ADC inputs that allow a line-level signal to be injected without passing through the preamps (and thus employing external preamps, for example), is a beneficial addition that offers the user additional flexibility.

To be more precise, the DB25 connectors (pictured here) offer some intriguing possibilities, namely, they can:

– serve as an insert line between the internal preamp and the converter.

– enter directly into the converters, with a microphone signal processing chain upstream (with preamps, analog compressors, for example) to keep the simplest path inside the interface between the input and the DAW, after the processing you wish to give to the microphone signal.

– mix with external processing, sending up to eight USB channels to eight line-level analog outputs, which can then be processed in an outboard effects chain and then sent back to the DAW through the ADC inputs. (The selection of insert and ADC modes is precisely controlled through the Audient mix software.) 

Mixer software: routing, inserts/ADC and monitoring functions

Audient’s elegant and ergonomic console software is a pleasure to use, as always. There’s no need to explain its basic functions (faders, panning, phantom power), which are all obvious to the user. The quick overview is that it consists of a display of mixer channels that control analog inputs (left), digital inputs (center), and USB channels (right). You can choose which of these sections to display. The following section, located on the right, allows you to switch between mixes. You can configure up to five different mixes, including the Master mix and four Cue mixes. Clicking on a mix brings up its independent channels. Each mix has a different color code. Finally, a light gray section on the right allows you to control the channel sets displayed (analog, digital, USB) and the various monitoring functions (alternative listening, mute, phase).

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From this known architecture, the software adapts to the possibilities offered by the iD48: selection of ADC inputs or insert lines. The software also lets you select some really useful functions, such as the attenuation level of the DIM function or the fine-tuning of the ALT output (plus or minus 6 dB), or the mono listening source (left, right or center). Added to this is a routing matrix that lets you send any mix (including DAW THRU, i.e., the output of your sequencer software) to any output: monitoring on a 6.35 mm (1/4-inch) jack, line level via the DB25 connector, digital outputs (ADAT or S/PDIF) and talkback. This last function is interesting, as it allows an external talkback source to be used, and therefore, no interface channel to be used for a communication function.

Measurements: dynamics, distortion, latency and frequency responses

The iD48 works at a maximum resolution of 24 bit/96 kHz. A quick look at RTL Utility tells us that the actual latency is as follows:

To test the interface, we ran a benchmark using our trusty APx515 from Audio Precision. As usual, we’re publishing the results obtained in THD, THD+N, channel deviation and IMD (except for the headphone output), then the amplitude response of each measured channel. For all configurations, I adjusted the gain to obtain the best possible result.

Dynamic range: 108,2 dB (AES-17, A-weighted)

1 – Let’s start with the line inputs: 

Deviation: ±0.49 dB (reference frequency: 1 kHz)

THD+N: –95 dB / THD: –96 dB (@ 1 kHz)

Intermodulation distortion: –84,8 dB (SMPTE type, @ 1 kHz)

In amplitude, we measured: 

2 – Let’s move on to the micro inputs:

Deviation: ±0.1 dB (reference frequency: 1 kHz)

THD+N: –96 dB / THD: –106 dB (@ 1 kHz)

Intermodulation distortion: –95.8 dB (SMPTE type, @ 1 kHz)

Amplitude:

Max gain: 68.2 dB (mic input, @ 1kHz)

3 – What about the headphone output?

Deviation: ±0.11 dB (reference frequency: 1 kHz)

THD+N: –96 dB / THD: –107 dB (@ 1 kHz)

Amplitude:

4 – And finally, the line output:

Deflection: ±0.03 dB (reference frequency: 1 kHz)

THD+N : –92 dB / THD: –103 dB (@ 1 kHz)

Intermodulation distortion: –93.9 dB (SMPTE type, @ 1 kHz)

Amplitude : 

Technical characteristics

• 19 inch 1U rack format  

• USB-C connection; 24 bit / 96 kHz max. 

• 8 mic/line inputs on XLR/jack combos, +48 V independent per channel; HPF and PAD. 

• 2 instrument inputs (6.35 mm jack) on front panel. 

• 4 TRS monitor outputs (1/2 main + 3/4 ALT). 

• 2 headphone outputs with independent settings. 

• 2× ADAT In + 2× ADAT Out (up to 8 additional I/Os depending on frequency). 

• Word Clock In/Out (BNC). 

• 2 DB25  connectors: 8 line outputs / insert sends + 8 direct ADC inputs / insert returns. 

• LED multi-section VU meter, rotary encoder, ALT, TB, F1, F2 buttons. 

• Mixing software with five mixes (Master + 4 Cues), DIM, ALT ±6 dB, mono L/R/C, flexible routing matrix and external talkback. 

FAQ

Can I bypass the internal preamps to use external ones?

Yes. The “ADC” inputs accessible via the DB25 allow you to directly attack the converters at line level, without going through the internal preamps. 

Are the inserts analog?

Yes. The first DB25 provides eight insert outputs/sends before conversion, and eight returns via the second DB25, allowing the insertion of analog processing between preamp and ADC. 

How many independent headphone mixes can I create?

Up to four Cue mixes in addition to the Master. Each has its own settings and routing, which can be sent to the headphone/line outputs of your choice. 

Is the latency suitable for live-monitoring recording?

Yes, the interface displays low latency, and the software allows direct monitoring. 

Does the iD48 support Word Clock for an existing digital studio?

Yes, the interface offers BNC Word Clock input and output, allowing it to integrate as a clock master or slave. 

Can I reamp or send stems to outboard?

Yes. The eight line outputs via DB25 allow you to send tracks from your DAW to external effects and then back via the ADC inputs.