Introduction - Bowers & Wilkins Nautilus Owner's Manual

Introduction

B&W monitors are widely considered to
be the benchmark in music reproduction
by professional musicians and audiophiles
alike. The Matrix # 801 has become the
industry standard monitor in recording
studios around the world, and it would be
easy to rest on our development laurels.
However, the team of audio scientists
at B&W's Research Laboratories at Steyning
are perfectionists. For them, there are
always areas which could be improved
upon or refined.
Company founder, John Bowers, was
an exemplar of the type. For him, the most
glaring compromise in loudspeaker design
lay in the cabinet. The standard rectan-
gular enclosure only partially achieves its
goal of absorbing the rear radiation from
the drive unit.
Worse, it contributes resonances and
reflections from the inside, and diffraction
and reflection from the outside.
The B&W breakthrough of Matrix
cabinet construction offered a significant
improvement to the panel stiffness of the
rectangular box, but ultimately, the
solution, John felt, was to remove the
cabinet completely and create a dipole
source. Sadly, time and ill-health
intervened to prevent John Bowers from
exploring this avenue of research further.
Custody of this work was passed to
Matrix inventor and top acoustic designer,
Laurence Dickie, with an enviable record
of transducer and cabinet problem solving.
Laurence had been experimenting with
drivers mounted in the curved surface
of a cylinder and encountered results
not dissimilar to those of the dipole.
Namely, that external cabinet effects
could be virtually eliminated and the
intrinsic sound of the unit heard.
He used a ring magnet outside the coil with
a thin-walled cylindrical pole piece to allow
a smooth transition from dome to enclosure.
Only one type of enclosure will provide
absolute freedom from aberration – the
infinite pipe or waveguide.
Excitingly, it became possible to
imagine that an entirely waveguide-based
system could actually work. Research
showed that the exponentially tapered pipe
was an even better absorber than the cylin-
der. So complete was its absorbing action
that the pipe could be left open or closed.
This was the breakthrough. Thereafter,
the usual disciplines of the acoustic
engineer's art came into play. Juggling the
variables of driver diameter, dispersion,
break-up, excursion, practicality, and of
course, economics.
It was decided that the system should
be four-way with 300mm (12in), 100mm
(4in), 50mm (2in) and 25mm (1in) units
– all mounted in tapered lines within a
diffraction limiting enclosure.
The enclosure evolved from the original
cylinder into the sleek rolling vent design
you have purchased. The massive rolling
vent disposes of rear bass driver radiation,
whilst the exponential line loaded
transmissions effectively deal with internal
reflection and external diffraction at mid
and high frequencies.
The drive for sonic purity is reinforced
by using an active crossover design
allowing separate amplification of each
drive unit, cutting out component crosstalk
and driver inter-reaction. Overall, the
elimination of straight lines defeats
diffraction and helps achieve virtually
transparent music reproduction.
What results is arguably the most
musical loudspeaker ever made.