Most loudspeaker companies tend to take an evolutionary approach to product development; they use the same basic design and refine it over time, a bit like a BMW 3 Series car. This is what B&W has been doing with its 800 series since the Nautilus design came about in 1998. That was the point when the cabinets went from being square to rounded, and the Nautilus ‘head’ was introduced. There have been three iterations of that model, the main change being the gradual introduction of a diamond tweeter across the entire range, starting back in 2005. For the latest D3 800 series models, there has been a ground up revision of pretty much every element of the various models. In fact, the only parts that have carried over from the previous range are the diamond dome itself and the cable terminals, which is good because they were (and are) rather nice.
At a glance, the D3 models look very much like their predecessors, especially the 802, but take a closer look and you’ll see that they are slimmer, deeper, and proportionally different. The ‘head’ is smaller in diameter, but longer and less tapered. Perhaps most significantly, the driver it holds is no longer yellow Kevlar but silver ‘Continuum’, a proprietary material that has been in R&D for several years waiting patiently for the new generation models. The head itself is no longer made of Marlan, but cast in aluminium for greater stiffness where it matters. You wouldn’t think that something as solid as synthetic stone could be vibrated by a relatively small drive unit, but it turns out that Marlan is not very stiff at 2kHz, which is bang in the midrange so crucial to this application. This, like most of the changes made for D3, is a means of reducing cabinet vibration and results in a ‘quieter’ loudspeaker that adds less of its own character to the music.
The cabinets are still made of curved plywood but, and this is strangely not obvious, the curve has been reversed. The bass drivers have to be mounted on aluminium rings to make this work and the open ‘end’ of the U-section woodwork is now covered with a full height aluminium heatsink that holds the crossovers and terminals. Internally the matrix structure that gives the cabinet rigidity has fewer parts but is made from plywood that’s much beefier than the MDF it replaces, they also feature metal parts to provide maximum rigidity at the point where the drivers are fixed. In the past, Bowers & Wilkins has used computer modelling to design its drive units; for D3 this technology has been used on the cabinet as well and this is why the designs have changed so much. The new ‘Turbine’ head is smaller and wider at the back for stiffness; it’s made from a single aluminium casting and has internal bracing in the form of radial fins. To stop it ringing, the whole thing is damped with TPE (thermoplastic polymers), as used in modern Kango breakers.
The change of colour and name of the midrange driver is fairly significant as well; apparently they have been working on Continuum since 2007, but couldn’t get consistent enough results for the 2010 800 series revision. The company now has a patent pending on it. It’s a woven material like Kevlar, but is damped on the back; apparently this makes the midrange faster, has lower noise, and better self-damping. More critical is that Kevlar is anisotropic; its performance depends on the direction of weave. I recall Bowers & Wilkins mentioning that driver orientation is critical and this must be why.
The bass drivers are no longer Rohacell, but consist of carbon fibre skins over a sintactic foam core that the company is calling ‘Aerofoil’. Unlike pretty well any other driver these cones are thicker in the middle than at the in- and outside. This stiffens the cone while keeping weight down and helps to push the first break-up mode to between 400 and 550Hz. The tweeter is still a diamond dome, but it has a new motor assembly, and it sits in a milled aluminium pod that’s shorter than it used to be. It now has a permanent grille to protect the very fragile diamond dome and avoid the thousand pound cost of having it replaced. Apparently, R&D spent many hours sweating over the precise nature of the grille frets or holes, in order to find a design that did not compromise the sound.