Полочная акустика — B&W (Bowers & Wilkins) 805 D4

The 805 D4 is the compact two-way monitor in Bowers & Wilkins' 800 Series Diamond, the fourth generation of the line first launched in 1979 and developed at the company's Worthing research facility. It is the only stand-mount in the current 800 Series and shares its tweeter technology and cabinet construction principles with the 804 D4 and larger towers above it.

Key specs that matter

It uses one 25 mm diamond dome tweeter and one 165 mm (6.5 in) Continuum cone bass/midrange in a vented-box system. Frequency response is 42 Hz to 28 kHz (+/-3 dB), with an extended frequency range of 34 Hz to 35 kHz at -6 dB. Sensitivity is 88 dB at 2.83 V/1 m, nominal impedance is 8 ohms, and the recommended amplifier power is 50 W to 120 W into 8 ohms on unclipped programme. Second and third harmonic distortion at 90 dB is below 1% from 90 Hz to 20 kHz and below 0.3% from 120 Hz to 20 kHz. The cabinet measures 440 x 240 x 373 mm and weighs 15.55 kg per speaker.

Engineering and use context

The diamond dome combines low mass and very high stiffness, which pushes its first break-up mode far above the audible band. The dome is mounted in B&W's Solid Body Tweeter-on-Top enclosure, milled from a single aluminium block, with an elongated tube-loading chamber behind the dome and decoupling from the main cabinet. B&W's Continuum cone uses a composite construction designed to avoid the abrupt changes in behaviour that occur in conventional cones as they move into break-up. The D4 generation introduced a Reverse-Wrap cabinet, which curves the side panels towards the rear and frees a dedicated compartment for the crossover, isolating capacitors from air pressure inside the enclosure. Internal Matrix bracing, an anti-resonance plug in the drive unit and a dimpled Flowport complete the construction, and the speaker terminals were upgraded for this generation. Standard cabinet finishes are gloss black, white, satin rosenut and satin walnut, and a later 805 D4 Signature version adds a revised crossover mounted on aluminium spines that also act as a heatsink.

Pairing

The 805 D4 is not a difficult load, but its dip to around 4.6 ohms rewards an amplifier with a solid power supply rather than bare rated watts. B&W specifies a maximum cable impedance of 0.1 ohm. The dedicated FS-805 D4 stand places the tweeter at seated ear height and is designed to lock to the cabinet.

Alternatives

The 804 D4 moves to a three-way floorstanding design with a dedicated midrange and twin 165 mm bass cones.