Waldorf - Iridium Desktop MK2

The Waldorf Iridium Desktop MK2 is the second generation of the multi-engine desktop synthesizer that Waldorf introduced back in 2020. The original Iridium brought together wavetable, virtual analog, granular sampling, resonator, and kernel synthesis in a single instrument — sharing its engine with the larger Quantum keyboard — and has since become a go-to for sound designers, film composers, and anyone drawn to the kind of synthesizer where you can lose an afternoon in intricate timbral details and still feel like you've barely scratched the surface. Five years on, Waldorf has given the Iridium a meaningful upgrade. New CPU board, expanded RAM and flash memory, a refreshed design, and a fresh round of synthesis features that make an already deep instrument go deeper still.

The MK2 now allows for up to four layers of multitimbrality — up from two on the original — with layer, split, round-robin, and random-robin modes. This opens up a lot for sound designers, film composers, and anyone who likes stacking textures into rich, evolving arrangements. The expanded memory makes this possible: sample flash has doubled to 6 GB (preloaded with 2 GB of factory samples), and the factory library has grown to over 1750 patches, with a pretty staggering 7000 user slots available. The step sequencer now runs up to 64 steps for notes and parameters. A new Mutator patch randomizer — borrowed from Waldorf's Microwave plugin — is a great way to stumble into unexpected territory. The arpeggiator gains polyphonic modes, and microtonal tuning settings can now be saved per patch. Worth noting: the MK2 ships with OS 4.0, and existing Quantum and Iridium owners get a good share of these new features through the same update — Mutator, polyphonic arpeggiator, microtonal saving, and more.

Then there's Seeds — a sixth synthesis mode available to each of the three oscillators. Inspired by wavetable synthesis but working quite differently under the hood, Seeds generates timbral journeys from dynamic sub-oscillators (the "seeds") rather than from static waveform snapshots. You can combine these with ring modulation, FM, and noise to create evolving, complex textures. Waldorf ships a set of predefined soundscapes to get you started, but you can also build and edit your own. Alongside the existing five modes — wavetable, waveform, particle, resonator, and kernels — this gives each oscillator six distinct synthesis engines to choose from. The breadth is hard to overstate.

Two more features also deserve a closer look. Per-Note Parameter Locks, developed in collaboration with Aphex Twin, allow you to assign up to 16 individual parameter variations to each of the 128 MIDI notes — including oscillator synthesis mode and effect parameters. The changes are stored per patch and edited on a dedicated page. It's a powerful tool for creating timbral variety across the keyboard. Then there's Flavour, first introduced on Waldorf's smaller Protein synth, which adds subtle micro-variations in timing, pitch, and timbre across voices — a small detail that brings organic life to patches without you having to think about it. On the connectivity side, the MK2 adds a headphone output with level control, a USB-A host port (for storage media and MIDI devices), MIDI 2.0 compatibility, and a VESA 75 mount on the bottom for those who like their synths on a monitor arm. The rest of the I/O — stereo audio in/out, four CV inputs, gate/trigger/clock, DIN MIDI trio, USB-B, microSD — carries over from the original.

The Iridium has always been one of those instruments where you could spend months and still find new corners. With the MK2, Waldorf has made that space considerably larger. Deep. Expansive. More of everything that made the original worth your time!

Features:

• 16-voice polyphonic desktop synthesizer
• 3 oscillators per voice, each with 6 synthesis modes: Wavetable, Waveform, Particle, Resonator, Kernels, and Seeds
• Seeds: new waypoint synthesis mode using dynamic sub-oscillators with ring modulation, FM, and noise
• 4 multitimbral layers with layer, split, round-robin, and random-robin modes
• True stereo dual digital filters per voice (12/24 dB LP/HP/BP) with Nave, Largo, PPG, Quantum, and State Variable models
• Digital Former section with comb filters, bit crusher, drive, ring modulation, and formant filters
• 6 envelopes, 6 LFOs, Komplex Modulator with user-definable shape and morphing
• Per-Note Parameter Locks (up to 16 parameter variations per note, developed with Aphex Twin)
• Flavour control for micro-variations in timing, pitch, and timbre
• 40-slot modulation matrix with fast-assign mode
• Advanced arpeggiator with polyphonic modes
• Step sequencer with up to 64 steps for notes and parameters
• Mutator patch randomizer
• Microtonal tuning settings, saveable per patch
• 4×4 RGB pad matrix assignable to notes, scales, or chords
• 1024×600 touch screen with XY control and wheels emulation
• MPE capable
• Over 1750 factory patches, 7000 user patch slots
• 6 GB sample flash memory (2 GB factory samples preloaded)
• 5 effect slots per layer with various routing options (reverb, delay, chorus, phaser, flanger, drive, EQ, compressor, tremolo)
• Stereo audio out (2× TS), stereo audio in (2× TS), headphone out (TRS) with level control
• DIN MIDI In/Out/Thru, USB-B (device), USB-A (host)
• MIDI 2.0 compatible
• 4 high-resolution CV inputs, analog clock in/out, gate and start inputs
• MicroSD slot
• Sturdy metal case, 440 × 305 × 85 mm, 4.8 kg
• VESA 75 mount on the bottom, 19″ rack parts available