Bowers & Wilkins 801 D4

The 801 D4 is the flagship floorstanding loudspeaker in the 800 Series Diamond range — a three-way design that represents the full extent of Bowers & Wilkins' engineering capability. The return of the 801 designation is significant: this is a model name with decades of history in professional and domestic audio, and its reintroduction signals that Bowers & Wilkins consider the D4 generation worthy of the lineage. At its heart, every technology the 800 Series Diamond has to offer is present and working in concert.

Diamond Tweeter and Solid Body

The 801 D4 uses a diamond dome tweeter — not diamond-coated, but solid diamond, machined to a precise profile. Diamond is the stiffest natural material available, which means the tweeter dome resists deformation at high frequencies far more effectively than any metal or fabric alternative. The result is a treble that remains composed and detailed well beyond the limits of audibility. The tweeter is housed in a Solid Body enclosure — a sculpted, cast aluminium housing precision-machined to minimise diffraction and provide a mechanically stable, resonance-free mounting point.

Tweeter-on-Top

The tweeter assembly sits above the main cabinet rather than being integrated into the baffle. This Tweeter-on-Top arrangement isolates the tweeter from the vibrations generated by the mid and bass drivers, keeping the high-frequency output clean and free from cabinet-borne colouration. It is a structural commitment to performance — it is not the simplest way to build a speaker, but it is the right way.

Continuum FST Mid-Range Driver

The midrange driver uses Bowers & Wilkins' Continuum cone material, mounted in a Fixed Suspension Transducer (FST) configuration that eliminates the conventional foam surround. Continuum was developed specifically to remove a sonic character that Bowers & Wilkins identified in their previous Kevlar cones — a particular resonance that, once heard in isolation, could not be unheard. The FST mounting reduces intermodulation distortion in the mid-range band, where the ear is most sensitive.

Turbine Head

The midrange driver is housed in the Turbine Head — an all-aluminium enclosure with a profile derived from fluid dynamics research. The ribs of the Turbine Head are not decorative; they are structural, breaking up the internal standing waves that would otherwise colour the midrange output. The Turbine Head is mechanically decoupled from both the bass cabinet below and the tweeter body above, so each driver operates in its own acoustically isolated environment.

Aerofoil Bass Cones and Anti-Resonance Plug

The bass section employs Aerofoil profile bass drivers — cones with a cross-section that varies in thickness from edge to centre, providing the optimal balance of stiffness and mass at each point across the cone surface. An Anti-Resonance Plug sits at the rear of the bass chassis, reducing back-wave energy within the motor system. Together, these technologies aim to deliver bass that is controlled and articulate rather than simply powerful.

Biomimetic Suspension

The spider — the component that centres the voice coil within the motor gap — uses a Biomimetic Suspension design inspired by natural structures. Conventional spiders introduce a degree of non-linearity as they move through their range of travel. The Biomimetic design maintains more consistent behaviour across the driver's full excursion, contributing to the 801 D4's composure at high listening levels.

Matrix Cabinet

The cabinet uses Bowers & Wilkins' Matrix internal bracing system. Interlocking aluminium panels are bonded inside the enclosure, subdividing the internal volume and dramatically increasing the rigidity of the cabinet walls. A resonant cabinet adds its own colouration to the sound; Matrix exists to prevent that. The D4 generation uses an upgraded Matrix design with more extensive aluminium reinforcement than its predecessors.

Technical Specifications

Who Is It For?

The 801 D4 is for the listener who has heard what the best systems are capable of and will not accept anything less in their own home. It demands a serious amplifier — something of genuine quality and power — and a room large enough to let it breathe. If you are building a reference system with no ceiling on ambition, this is the loudspeaker to start from.

Buying from Martin's Hi-Fi

Martin's Hi-Fi has been in Norwich since 1968. Elizabeth Gould runs the business today, and we stock only brands we have heard properly and stand behind. Martin's Hi-Fi is the second oldest Bowers & Wilkins dealer in the world, and the 801 D4 is available to hear in our Norwich showroom. Dave and Chris can walk you through the full 800 Series Diamond range, discuss amplifier matching, and help you understand exactly what the 801 D4 will do in your listening room. A private demonstration can be arranged at a time that suits you.

Contact us at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martin's page (https://www.martinshifi.co.uk/about-us/why-martins/). We are at 85–91 Ber Street, Norwich, NR1 3EY.

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