British audio specialist Bowers & Wilkins introduced its seventh-generation 800 Series Diamond Loudspeakers in 2021, continuing the lineage of the company’s flagship, first seen in 1979. The original 801 loudspeakers quickly became a reference standard, and later models were adopted by major recording studios such as Abbey Road and Skywalker Sound.

The 801 D4 is the 800-pound gorilla of the latest 800 series, well, actually, 480 pounds per pair. Once positioned in the listening room, these monoliths are the star attraction of any stereo sound system. And with the 801 D4 Signature, priced at US$55,000 (HK$429,605) per pair, audiophiles get some technological and aesthetic perks that go beyond the already impressive 801 D4, priced at US$35,000 (HK$273,385) per pair.

The 801 D4 Signature has been available for almost a year, and so it was high time we took a closer look at this rare and elusive audio gem. The basic configuration of the big floor-standers features a unique three-piece cabinet, curvaceously designed to accommodate two 10-inch woofers in the main section. These transducers employ B&W’s Aerofoil cone, a composite carbon-fibre skin over a light foam core of varying thickness, achieving maximum stiffness where required but lower mass overall. This improves transient speed and the impact of bass frequencies. Exclusive to woofers in the Signature are upgraded and improved magnets in the motor systems that deliver even more impressive control of low-frequency output.

Above the main cabinet is a six-inch composite Continuum cone midrange driver, which occupies an organically shaped, cast-aluminium Turbine head mid-range enclosure. On top of this is the one-inch diamond-dome tweeter that gives the 800 Series Diamond its name. More rigid than aluminium- or cloth-dome transducers, diamond-based domes (fabricated using the chemical vapour deposition of diamond material on a substrate) have a dynamic stiffness that eliminates breakup and ensures near-perfect linearity well beyond human audibility.

The tweeter, using an improved and more transparent grill mesh for the Signature, is enclosed in an anodised and tapered tube, one that’s milled from a solid block of aluminium to eliminate resonances inherent in traditional enclosures. A two-point decoupling system further isolates it from the midrange and woofers below. This is sophisticated engineering, as far removed from cones in a box as a McLaren Speedtail is from a Ford Model T.

Further enhancing the Signature’s performance is a redesigned crossover that uses upgraded bypass capacitors throughout. Its frequency range is stated as an impressive 13 Hz to 35 kHz, and a nominal impedance of 8 ohms, dipping to 3 ohms. Due to its medium sensitivity of 90 dB, the manufacturer recommends a minimum of 50 watts, though considerably more power will not be wasted on the big B&W; after all, these Signatures deserve the very best amplification and source components available.

Each 801 D4 Signature enclosure requires a complex fabrication process that uses bent plywood with an elaborate internal-matrix bracing structure of interlocking panels for maximum rigidity. A stiff aluminium plate on the inside face of the cabinet further eliminates resonance, with a cast aluminium, leather-wrapped top plate.

Importantly, the Signature Series is available in only two exclusive cabinet finishes. The mile-deep Midnight Blue metallic paint, which requires 18 hours to apply, is identical to the paint used on the company’s iconic Nautilus loudspeaker. Trimmed in blue Connolly leather on the top plate, this is contemporary sculpture that makes music. More traditional listeners will likely opt for the exquisite California Burl Gloss wood veneer, trimmed in black Connolly leather. Bowers & Wilkins is quick to point out that the veneer is sustainably sourced, engineered wood from Italian specialist ALPI. With 14 coats of lacquer, followed by sanding and polishing, each single loudspeaker enclosure requires more than 24 hours of labour to complete.

We called the original Bowers & Wilkins 801 D4 “a bit of a bargain in the world of top-echelon loudspeakers.” The Signature raises the price, and adds a lot of pizzazz, while remaining a solid deal in the high-end-audio landscape.

Click here for more photos of the Bowers & Wilkins 801 D4 Signature loudspeaker.