The XOP standard

We won't trade truth for theatre.

XOP exists for the unreasonable listener — the one who wants to hear what was recorded, not a flattering impression of it. Every curve of the cabinet and every gram of the cone serves one of three ends, and each is proven with measurement.

I.

Clarity

Low distortion and controlled directivity keep dense mixes legible — every voice and instrument holds its own place in the room.

II.

Scale

Sealed bass systems that pressurise a real room without strain, delivering physical weight that stays clean as it grows.

III.

Composure

Linear dynamics at live levels. No hardening, no compression — the sound holds its shape when lesser designs break up.

Under the skin

Clarity, scale and composure — bought driver by driver.

Those three virtues aren't slogans. They're paid for with some of the finest transducers in the world — chosen for the job, never to a budget — and the cabinet and DSP are then engineered around them.

BlieSMa beryllium tweeter

A 25 mm BlieSMa T25B beryllium dome — so light and so stiff that its first breakup sits beyond human hearing. Extended, effortless, utterly uncoloured treble, from a tweeter widely regarded among the finest in the world.

Purifi midrange

A 6.5″ Purifi PTT6.5 midrange — engineered to among the lowest distortion ever measured in a driver of its kind, thanks to a patented surround and ultra-linear motor. Uncanny clarity, true timbre.

FaitalPRO 15″ woofer

A 15″ FaitalPRO woofer — 98 dB efficient and built for high-output systems, clean and uncompressed where lesser drivers harden. The scale and slam of live music, without a hint of strain.

Eminence 21″ bass

For the subwoofers: a 21″ Eminence NSW6021 on a 2,500-watt neodymium motor with 21 mm of clean travel — vast, controlled displacement that pressurises a real room and never runs out of headroom.

The Collection

A small range, built to be kept.

From a 1.5-metre sculptural floorstander to a 125-kilogram reference subwoofer — each model is designed in-house and cut on our own machine. No filler, no contract factory.

XOP MP1 flagship three-way floorstanding loudspeaker in red

Flagship · Three-Way Floorstander

MP1

A 1.5-metre sculptural floorstander — a BlieSMa beryllium tweeter, a Purifi midrange and a 15″ FaitalPRO transmission-line woofer, conceived to outperform the world's reference floorstander.

By commissionFull spec →

Reference Subwoofer

AP1-S

A 21-inch sealed active subwoofer — 1,100 watts of onboard DSP, seismic spring isolation as standard. Serials 001 & 002 in build now.

POA · autumn 2026Full spec →

XOP HP1 three-driver 21-inch sealed bass tower in red

Statement Bass Tower

HP1

Three 21″ Eminence drivers in three sealed chambers, driven by 4 kW of onboard amplification — two metres of room-pressurising, plug-and-play low end. Balanced XLR in, presets, done.

By commissionFull spec →

The MP1 · Flagship Loudspeaker

The reference, reimagined.

A three-way, actively tri-amplified floorstander built to a single brief: exceed the world's reference standard in clarity, midband intelligibility and dynamic authority — inside a sculptural body that owes nothing to anyone. The tapered transmission line wraps around itself to form the signature open "through-window"; acoustic function, expressed as sculpture.

FormatThree-way · active tri-amp · transmission line

Drivers25 mm BlieSMa beryllium · 6.5″ Purifi · 15″ FaitalPRO

CrossoverActive DSP · LR4, 24 dB/oct · 380 Hz / 2.8 kHz

Response28 Hz – 40 kHz · ±1.5 dB, 100 Hz – 15 kHz

Max SPL≈ 112 dB · peak, in-room

AmplificationOnboard DSP tri-amp · 500 / 500 / 100 W per driver

Control & inputsBalanced XLR & RCA · voicing presets · 230 V mains

Dimensions1520 × 550 × 700 mm · H×W×D, with plinth

Weight≈ 75–85 kg each

Modelled system response28 Hz – 40 kHz

Modelled from the driver parameters · verified by measurement on each unit.

Piano-gloss finish, hand-lacquered — true mirror-imaged pairs, their through-windows facing each other like bookends.

Commission the MP1 ↓ Spec sheet (PDF)

XOP MP1 flagship floorstander, sculptural spiral form

XOP HP1 three-driver 21-inch bass tower, two metres tall, next to a six-foot figure for scale

The HP1 · Statement Bass Tower

Two metres of pure foundation.

Three 21-inch drivers stacked in three independent sealed chambers, driven by a single 4-kilowatt onboard amplifier. A floor-to-ceiling column of effortless, articulate low end — the bass the mains were always meant to stand on.

FormatSealed · active · triple 21″ array

DriversThree 21″ Eminence · three sealed chambers

Amplification4 kW onboard amplification · balanced XLR · DSP presets

AlignmentSealed · ≈ 220 L net per chamber · DSP-extended

Output≈ 132 dB peak · in-room to ≈ 14 Hz

Dimensions≈ 2060 × 620 × 560 mm · H×W×D, with plinth

Control & inputsBalanced XLR · DSP presets · phase · 230 V mains

SetupPlug-and-play · XLR in, mains, Preset 1

Modelled response · sealed vs DSPto ≈ 14 Hz

Modelled from the Eminence NSW6021-6 parameters · three sealed chambers.

Hand-built to order in any XOP finish — one sculpted column per side.

Commission the HP1 ↓ Spec sheet (PDF)

The AP1-S · Reference Subwoofer

Twenty-one inches, floating on springs.

A single-driver, DSP-controlled sealed subwoofer built around a 21-inch Eminence driver and a bridged 1,100-watt Class-D amplifier. Deliberately over-damped, then extended in the digital domain — bass that stays composed when the room is working hard.

FormatSealed · active · single 21″

DriverEminence NSW6021-6 · 21″ · 6 Ω · 21.8 kg · BL 33.8 T·m

AmplifierBridged Class-D · ~1,100 W @ 6 Ω · onboard DSP/FIR

Control & inputsBalanced XLR & RCA · DSP presets · phase · 230 V mains

AlignmentQtc ≈ 0.41 · Fc ≈ 38 Hz · DSP-extended

Output≈ 122 dB peak · in-room to ≈ 16 Hz

Cabinet≈ 1060 × 735 × 710 mm · W×H×D, + plinth · ≈ 305 L net sealed

Isolation4 × encapsulated spring mounts · standard

Weight≈ 125 kg

Serials 001 & 002 complete autumn 2026 — the build diary, mistakes included, ships with the speakers.

Commission an AP1-S ↓ Spec sheet (PDF)

The range at a glance

Three speakers, one system.

A deliberately small range, designed to stand alone or work together — a full-range flagship, a statement bass tower, and a reference subwoofer to sit beneath either.

	MP1	HP1	AP1-S
Role	Flagship floorstander	Statement bass tower	Reference subwoofer
Format	Three-way active tri-amp	Sealed triple-21″ active	Sealed single-21″ active
Drivers	25 mm BlieSMa · 6.5″ Purifi · 15″ FaitalPRO	Three 21″ Eminence	21″ Eminence NSW6021
Low end	28 Hz	to ≈ 14 Hz	to ≈ 16 Hz
Max SPL	≈ 112 dB	≈ 132 dB	≈ 122 dB
Amplification	DSP tri-amp · 500 / 500 / 100 W	4 kW onboard	Bridged 1,100 W
Size (mm)	1520 × 550 × 700	≈ 2060 × 620 × 560	≈ 1060 × 735 × 710
Weight	≈ 75–85 kg each	by commission	≈ 125 kg

Figures are design targets, verified by measurement on every unit built. Enquire for full specifications.

↓ Download the range brochure (PDF)

Made yours

Any model. Any finish you can imagine.

Every cabinet is hand-lacquered to a deep gloss — across the whole range. Choose a house finish, or commission a bespoke livery, right down to a full Union Jack.

Ferrari Rosso

Metallic Silver

Gloss White

Union Jack

Bespoke

The Workshop

Handbuilt, not assembled.

No flat-pack. No contract factory. Our own 1.5-metre CNC cuts every panel; two-layer laminated walls and an 80-millimetre faceted baffle are glued, filled and finished by hand — on a CNC we built by hand from a kit, in a workshop in Staffordshire.

01

Cut in-house

Every panel machined on our own CNC — the baffle from two 40 mm halves glued to one solid 80 mm face.

02

Braced to the core

Twin ring-hub X-braces lock all four walls at the driver's centre of mass; a sealed pod isolates the amplifier from 305 litres of working air.

03

Signed & numbered

Assembled, measured and finished by hand in Staffordshire — each cabinet signed and numbered, with its honest build diary in the crate.

The star-hub brace inside a primed XOP cabinet, locking all four walls at the driver's centre of mass

Mark, founder of XOP Acoustics, at the CNC in the Staffordshire workshop

The maker

One man who couldn't accept "that'll do."

XOP is the work of Mark Poxton. By profession an analyst, he spends his days taking problems of bewildering complexity and resolving them into something clear, correct and simple — for clients who don't get to be wrong. He is also, by temperament, unable to accept "good enough": the sort of man who builds his own homes and commissions rather than settles, because "that'll do" is the one answer he can't live with.

He turned that obsession on the loudspeaker — three years from the first sketch to the first panel cut, measuring everything and taking nothing on faith. The engineering around it is drawn from the best specialist talent in Britain, and it all converges in Staffordshire, where every cabinet is assembled, measured and finished by hand, and signed before it ships. Not a faceless factory. Not a lone hobbyist. One exacting vision, built with the best in the country.

Where it all began →

Radical transparency

We publish what others hide.

AP1-S — modelled responsecomputed from driver parameters · Fc 38 Hz · Qtc 0.41

DSP-extended sealed alignmentModelled from the driver's Thiele-Small data · every unit measured

If we claim it, we measure it. Every cabinet is characterised before it leaves — and the numbers travel with it, in a build diary that records the honest story of its making.

✦Sealed by design. Qtc ≈ 0.41 for a naturally over-damped, articulate low end.
✦DSP-extended. A Linkwitz transform reaches below the natural roll-off without unsealing the box.
✦Isolated amplifier. A sealed pod keeps 305 litres of air off the electronics — the alignment stays true.
✦Seismic isolation. Encapsulated spring mounts are standard, not a £2,000 accessory.

Commissioning

How a pair comes to be.

Every XOP is built to order, in a limited run. There's no shelf stock — there's a build queue, and a place in it with your name on it.

01

Enquire

Tell us your room, how you listen, and the finish you have in mind. We'll tell you honestly which model fits — if any.

02

Specify

We agree the model, the finish and any bespoke details, and confirm where you sit in the build queue.

03

Build

Your cabinets are cut, assembled, hand-lacquered and measured — every step logged in your build diary.

04

Deliver

Delivered by arrangement, serial-numbered, with its measurement card and the diary of its making.

Prices are by commission and depend on model and finish. Enquire for pricing and lead times.

Good to know

Questions, answered plainly.

Why active and DSP-controlled, rather than passive?

Because it removes the compromise. Each driver gets its own dedicated amplifier and a crossover computed in the digital domain — flatter response, tighter control, and driver protection that lets you use every watt without fear. It is the same reason the world's best studio monitors went active long ago.

How long is the wait?

Every XOP is built to order in a limited run, so there is a build queue rather than shelf stock. We confirm current lead times when you enquire — expect a matter of months, because the cabinet, hand-lacquering and measurement stages are not rushed.

How are they delivered and installed?

By arrangement. These are serious objects — the AP1-S alone is around 125 kg — so we plan the logistics and placement with you rather than leaving a pallet at the kerb.

Are they guaranteed?

Yes. Every XOP is guaranteed against defects in materials and workmanship, with the full terms set out in your commission agreement. Because each speaker is measured before it ships, we know exactly how yours behaves — and so do you.

Do you really measure every one?

Every cabinet is characterised before it leaves the workshop, and the measurement data travels with it in the build diary. If we claim it, we can show it — the honest numbers, this cabinet, not a brochure ideal.

Can I hear one first?

Where possible, yes — talk to us. Auditions and commissions are arranged individually. Tell us your room and how you listen, and we will take it from there.

The art of truthful sound.