Bowers & Wilkins manual PV1 Concept

These effects are related to the ratio of the sound

wavelength to the dimensions of the enclosure. The

resulting pressure and force gradients allowed the

reintroduction of bending forces on the walls of the

sphere, which raised the level of radiated sound and

coloration. Going back to our soap bubble analogy it

could be likened to the way a bubble flexes as it moves

through the air.

The obvious course to ameliorate this effect was to add a

second driver to power the enclosure from the opposite

end. Because of symmetry, this effectively halved the

volume loading each driver and doubled the frequency at

which these two effects began to cause a problem. The

second prototype, shown here, used two 380mm (15 in)

diameter drivers, one mounted at each end of a steel

marine floatation device. This prototype was capable of

producing prodigious levels of clean, articulate bass, but

was hardly a viable commercial proposition. Furthermore,

the resonances were still only just outside the effective

bandwidth of the device, due to its large dimensions.

However, the stage had been reached where a more

compact and visually appealing product could be

developed.

PV1 - Concept

The PV1, launched in June 2004, was developed directly from this prototype. From a sphere that comfortably passes through a basketball hoop, it creates truly extended bass that defies its diminutive and gorgeous exterior in both quality and quantity.

Although the Pressure Vessel concept was proven in very large enclosure, it was obvious that its prime technical merit of reducing cabinet stress was always going to find a particular relevance with a smaller product. Indeed, the PV1 represents a joyous meeting of minds for both engineer and industrial designer.

The problems inherent to small subwoofers are often compounded further by the industrial designer’s desire to shave off centimetres here and there. The beauty of the PV1 is precisely that its non-bending cabinet design permits the use of a relatively thin aluminium shell, maximising the internal volume and therefore minimising the amount of equalisation required from the amplifier.

Early pressure vessel prototype