Coltrane Supreme Extreme: engineering without limits

We’ve always believed that real progress in audio comes from removing the usual limits — and trusting our instincts. When our design team has the freedom to explore bold ideas, innovation follows. With Leif Olofsson leading the way, we pursued that philosophy without compromise.

Coltrane Supreme Extreme is the result. Not born from a product brief, but from a desire to take our craft further — to shape a loudspeaker so refined, so ambitious, that it expands what we thought was possible in high-end audio.

This is the most ambitious project we’ve ever undertaken. Years in the making, Coltrane Supreme Extreme is the result of uncompromising engineering, obsessive material selection, and the kind of deep listening that only comes with time and experience. It represents a new summit not only for us, but possibly for loudspeakers as a whole.

Coltrane Supreme Extreme is a four-tower loudspeaker system — a dual-tower, five-way design with dedicated bass and main towers. Each is optimised for mechanical isolation and maximum sonic control. The cabinets use a carbon fibre monocoque construction, reinforced with a sandwich of aluminium and solid wood. This creates an acoustically inert structure with incredible rigidity and transparency.

1" and 3" diamond plus a 7" beryllium driver

The driver configuration is our most advanced to date. Coltrane Supreme Extreme features a 1” pure diamond tweeter and a 3” pure diamond high midrange, delivering effortless clarity and upper-frequency detail. At the centre of Coltrane Supreme Extreme is a 7” pure beryllium midrange — the largest ever created — designed to handle the critical vocal band with speed, control and breathtaking realism. Supporting this are four 8” Crystalid mid-bass units, built from an exclusive ceramic-based material that’s remarkably light and stiff, offering performance characteristics well beyond typical ceramic materials.

For the low-end, we’ve developed a powerful bass tower using five 10” aluminium sandwich bass drivers and ten 10” passive radiators. Together with the main towers, the system covers an exceptional frequency range of 17–60,000 Hz (±2 dB), ensuring detail and coherence across the full audible spectrum and beyond. The result is a deep, tightly controlled bass performance that remains coherent at every volume.

Coltrane Supreme Extreme is fitted with Jorma Paragon wiring from Jorma — their highest-grade flagship cabling, selected for its exceptional purity and value — and uses a proprietary first-order crossover with custom-built components. Signal path integrity is preserved throughout, aided by Marten’s bespoke bi-wire terminals. Upgraded Marten Isolators — integrated into a mirror-polished stainless steel stand — allow the units to be free from the listening environment, greatly enhancing resonance control.

Each speaker takes more than 800 hours to build by hand at our Swedish facility, and is offered in four finishes: Matte Walnut, Matte Cherry, Matte Maple, and Matte Oak. Because of its scale, Coltrane Supreme Extreme is best suited to environments that can support its full potential — both acoustically and spatially.

The first public display took place at High End Munich 2025. The world premiere listening session will be held in August in Hong Kong, followed Tokyo International in October. Other international demos are still being planned, so watch this space.

Coltrane Supreme Extreme is more than a new flagship. It’s a statement — of who we are, what we believe, and what’s possible when you build without compromise.

When the feeling is real.

We don’t just want to hear music. We want to feel it—deeply and without compromise. Coltrane Supreme Extreme was born from that desire. A five-way, dual-tower speaker that removes every barrier between artist and listener. It’s the closest we’ve ever come to pure sound.

Hear what was always there.

This is where the voice gives form to feeling. The diamond tweeter and high midrange bring breathtaking clarity and articulation. The beryllium midrange wasn’t the goal—just the perfect solution. And the new Crystalid mid-bass drivers reveal the subtle textures where true emotion lives.

Challenge Everything.

Building Supreme Extreme meant starting from a blank page and asking harder questions. How can we optimise dynamics? Control resonance? Honour the music? The answer was clear: separate towers, each engineered with absolute precision to reveal the full emotional range of a performance.

Strength together

Solid wood and aluminium are bonded in a rigid sandwich structure. This layered construction reinforces the cabinet, controlling vibration and enhancing stability—so every frequency rings true, without interference.

Nothing in the way

The cabinet should disappear. That’s why we designed a seamless carbon fibre monocoque, layered with aluminium and solid wood. Inert and acoustically invisible—it lets the sound do its thing.

X marks the spot

This is the moment it all aligns. Every element of Coltrane Supreme Extreme—crossover, isolators, structure and flow—is designed to meet here, in perfect harmony. It’s the point where distractions fade and the music lands exactly where it’s meant to be: right in front of you, fully alive.