Status, October 2026: current. Audient still lists the iD4.
What it is
The iD4 MKII is a two-in, two-out USB-C audio interface from Audient, announced on 6 January 2021 as the second generation of the iD4, alongside the iD14 MKII (audioXpress, Audient product page). It is bus powered, and the MKII moved to USB-C with USB 3.0 power, which Audient says lets it supply a full 48 V of phantom power and gives the headphone amp more headroom.
The mic input, a combo XLR and jack socket on the back, uses the same discrete Audient Console mic preamp as the ASP8024-HE desk, with 58 dB of gain and phantom power at 48 V, 10 mA. A JFET instrument input on the front is designed, Audient says, to replicate the input stage of a valve amplifier for guitar and bass. The converters run at 24-bit up to 96 kHz. Outputs are a pair of balanced 1/4" line outputs for speakers and two headphone outputs, 1/4" and 3.5 mm, that work together and drive headphones up to 600 Ω (Audient tech specs).
On top sit two gain knobs, a Monitor Mix knob that blends the inputs with playback for monitoring without latency, a speaker on/off button and a large volume encoder; pressing the iD button turns the encoder into ScrollControl, a scroll wheel for plug-in parameters. A loop-back mixer captures the mic and computer audio together for streaming. It runs on macOS 10.11.6 or later, Windows 10 or later and iOS or iPadOS devices, and registration brings the ARC software bundle (iD4 MKII manual). The all-metal case has a 133 x 120 mm footprint, and the box holds the iD4, a USB-C to USB-C cable and a quick start guide. Audient covers it with a three-year limited warranty. The best audio interfaces guide sets it against the Focusrite Scarlett Solo.