B & W 801F Specifications

B&W 801F
¥ 450,000 (1 unit, released in November 1982)

Commentary

This floor-type speaker system has been adopted as a monitor speaker in many studios such as EMI in the UK.

The units are subjected to detailed tests such as vibration analysis tests using a laser interferometer. In addition, units with a characteristic difference of less than 0.25 dB are assembled as one pair.
Also, the actual measurement data was attached to each completed system.

A 27 cm cone type woofer is installed in the low range.
The cone is made of Bexstrain, a highly crystalline, highly rigid polymer with excellent linearity and resistance to distortion and deflection in response to low-frequency transient input. The cone stroke is 6 mm to provide a maximum sound pressure level comparable to the 120 dB of Live Sound.

The mid-range is equipped with 10 cm cone type mid-range.
The diaphragm is made of aromatic polyamide fiber with excellent transient characteristics and linearity. Polyamide fiberglass, which is almost the same as that used for heat treatment of spacecraft, is resin-processed by a special processing method patented by B & W.

A 2.6 cm dome-shaped tweeter is installed in the high range.
The diaphragm is woven of polyester single fiber to ensure frequency characteristics up to the outside of the audible band.
Nickel cobalt with high magnetic flux density is used for the magnet, and by making the unit volume as small as possible, dispersion in the high range is improved.

The Network Division has introduced computer analysis technology and is designed by applying a design technique called numerical optimization developed in-house. This system combines the characteristic data of each unit with circuit constants to simulate the operation of a crossover network on a computer display. It can pursue ideal connections between units with high accuracy.
We also use high-quality network components to prevent deterioration of sound quality.

Equipped with an APOC (Audio Powered Overload Circuit), which was developed for the first time in the world as a protective circuit, it prevents damage to the unit due to excessive input caused by accidents such as falling of the microphone stand in the studio.
The APOC system reads the voltage applied to the voice coil of each unit, and when the limit value is exceeded within a certain period of time, the relay operates to cut the input signal, protecting the unit from thermal damage due to overload.
The red LED lights up when the APOC system is in operation, and when the overload condition is cleared, the LED turns off and the speaker operation automatically starts.

The enclosure of the enclosure has an independent block structure to reduce interference between units. Each unit is placed in-line with a step to compensate for phase shift between units and improve horizontal spread. In addition, detailed delay compensation is applied to eliminate the time lag that occurs in the crossover network itself.
The enclosure for the woofer is made of 25 mm particleboards with studs on both sides to improve airtightness. The inside is reinforced with 25 mm thick plywood in the shape of a frame to reduce resonance of the enclosure itself. The woofer is separated from the enclosure by a thick rubber gasket, and the surface vibration of the enclosure is improved by 12 to 14 dB by blocking propagation of vibration.
The mid-range enclosure uses a glass-reinforced concrete called fiber-cleat inside, and the hard-polystyrene enclosure is lined with fiber-cleat to improve vibration by 10 dB in the 300 Hz to 3 kHz band compared to wooden enclosures.
The tweeter and mid-range enclosures are separated from the woofer enclosure by a rubber mount and can be rotated to the left or right to adjust the directivity depending on the listening position.
All edges of the enclosure have been cut diagonally to prevent diffraction from disturbing sound localization.

The mid-range enclosure is equipped with a Sound Field Correction Controller on the back of the mid-range enclosure that enables you to adjust the mid-range and high-range levels according to the sound conditions in the listening room.

The total design is based on a form obtained from a scientific approach at the Pentagram Design Institute.
In addition, there were 2 kinds of variations of the exterior finish, walnut finish and black finish.