B&W Unveils New 800 Series
Most notable is the incorporation of a diamond diaphragm for the tweeter of the top units in the line, in place of the aluminum dome used in the past. This material was employed after Finite Element Analysis (FEA) indicated that the physical properties of other exotic materials, such as titanium and beryllium, did not offer significant advantages for audio performance despite being, variously, stiffer and/or less dense than aluminum. The production of the polycrystalline diamond diaphragms via a vacuum deposition procedure is expensive, and that is reflected in the retail pricing for these models. That said, I found it striking that the development engineers extolled, at length, the audible performance rather than the measurements.
The new series' tweeters, diamond and aluminum alike, are fitted with a suspension which relocates the free-air resonance down into the 300Hz range, several octaves from the crossover point. This permits a gentler electrical and more predictable acoustic HP filter roll-off and, as a result, B&W has been able to use a single carefully selected capacitor for the midrange-to-HF filter to achieve a smooth, second-order L-R response. Furthermore, B&W moved the tweeter mounting forward by one-half a wavelength to avoid the vagaries concomitant in polarity inversion, which is often used to compensate for network phase shift in second-order crossovers. This forward-mounted position is one of the few external identifiers of the new 800 series.
The other major change is in the composition of the woofer diaphragms, which are now constructed of a central 8mm layer of Rohacell, a polymethylacrylimide hard foam, between two laminae of carbon fiber. Both the animated FEA results and the performance tests clearly showed the advantages in stiffness, internal damping, and linearity over the paper-Kevlar material used previously. I was amused to hear Dr. John Dibb, senior development engineer, describing how a single Rohacell woofer cone could support his entire weight. Shades of Harold Leak standing on his original Sandwich cone in the 1950s!
The signature, with a small "s", feature of the 800 models, the yellow Kevlar FS-T midrange is retained, but with streamlined magnet structure and support. The general cabinet design—the distinctive Nautilus midrange and tweeter compartments, the matrix bracing, the dimpling of the port surface to reduce airflow turbulence, and the one-piece molded construction—is also retained. The crossover networks are refined and simplified, due to the improved driver performance.
The top models in the new line are three three-way units with all these features, including the diamond tweeter, FS-T midrange, and a supporting base that controls output from the LF port on the bottom of the main enclosure: the 800 with two 10" Rohacell woofers ($10k/speaker), the 801 with one 15" Rohacell woofer ($8k/speaker), and the 802 with two 8" Rohacell woofers ($6k/speaker). The 804 and 805 retain the Nautilus-inspired tweeter mounting, but use an FS-T midrange in a conventional enclosure and an aluminum tweeter but the three-way 803 models straddle this dividing line. The 803 is available with the diamond tweeter and three 7" Rohacell woofers (803D, $4k/each) or with an aluminum tweeter and two 7" Rohacell woofers (803S, $2750/speaker). Also updated are the three-way 804 with two 6.5" Rohacell woofers ($2k/speaker) and the two-way, stand-mounted 805 with a single 6.5" Kevlar bass-midrange unit ($1250/speaker).
Those are just the tip of the iceberg, as B&W fills out the line with four new center-channel models, including the humongous three-way HTM1 with three 8" Rohacell woofers ($8k/speaker), two surround speakers, and three subwoofers, all of which will come with 1000W amps—two with DSP-eq to make them very room-friendly.
I am certain that B&W's website will, in due course, offer technical and other information in exquisite detail, but it will never be able to convey the sheer beauty of these designs, which one cannot fail to appreciate on sight. Unfortunately, the press presentation did not favor us with an audition and that is something we all greatly anticipate.