Bowers & Wilkins 804 - Manual (Page 5)

if the links are left in place, may cause
damage to the amplifier by shorting its
output terminals.
Fine tuning
Before fine tuning, double check that all the
connections in the installation are correct
and secure.
Moving the speakers further from the walls
will reduce the general level of bass. Space
behind the speakers also helps to create an
impression of depth. Conversely, moving
the speakers closer to the walls will
increase the level of bass.
If the bass is uneven with frequency it is
usually due to the excitation of resonance
modes in the room. Even small changes in
the position of the speakers or the listeners
can have a profound effect on how these
resonances affect the sound. Try mounting
the speakers along a different wall. Even
moving large pieces of furniture can have
an effect.
If the central image is poor, try moving the
speakers closer together or toeing them in
so they point at or just in front of the
listeners. (figure 4)
If the sound is too harsh, increase the
amount of soft furnishing in the room (for
example use heavier curtains), or reduce it
if the sound is dull and lifeless.
Test for flutter echoes by clapping your
hands and listening for rapid repetitions.
Reduce them by the use of irregular
shaped surfaces such as bookshelves and
large pieces of furniture.
Ensure the speakers stand firmly on the
floor. Whenever possible fit the spike feet
supplied after you have optimised the
positioning. They are designed to pierce
through carpeting to the floor surface.
Initially, screw the lock nuts fully onto the
spikes and screw the spikes fully into the
threaded inserts in the base of the speaker.
If the cabinet rocks, unscrew the
appropriate spikes until the speaker stands
firmly on the floor and lock them in place
by tightening the lock nuts against the
base. If you do not have a carpet, use a
protective disc under the spikes to protect
the floor surface.
For the most discerning listening, remove
the cloth covered grille as described below
in the section “Aftercare”. The tweeter is
very delicate and its grille should be left in
position for protection. For this reason the
grille retaining ring is designed to provide
the optimum acoustic environment for the
unit and the response is less smooth with
the grille removed.
Running-in period
The performance of the speaker will change
subtly during the initial listening period. If
the speaker has been stored in a cold
environment, the damping compounds and
suspension materials of the drive units will
take some time to recover their correct
mechanical properties. The drive unit
suspensions will also loosen up during the
first hours of use. The time taken for the
speaker to achieve its intended
performance will vary depending on
previous storage conditions and how it is
used. As a guide, allow up to a week for
the temperature effects to stabilise and 15
hours of average use for the mechanical
parts to attain their intended design
characteristics.
Ancillary equipment
Speakers of this ability deserve signals of
the highest quality. Choose your electronic
equipment and interconnecting cables with
care. We can give guidance on what to
look for when choosing ancillary
equipment, but cannot recommend specific
items. The standards of such products are
improving all the time and your dealer will
be able to demonstrate a variety of suitable
up-to-date products.
In the specification we recommend a range
of amplifier powers. The higher figure is
defined by the power handling capability of
the speaker. When calculating the power
handling, it is assumed that the amplifier is
not run into clipping, which distorts the
frequency power spectrum of the signal,
and that the signal is normal programme
material. Test tones from oscillators and the
like are not applicable. The lower figure is
the minimum we consider necessary to
achieve reasonable listening levels without
audible distortion in the smaller room (less
than 60 m
3 or 2000 cu ft). The higher the
power you use, the less likely you are to
experience amplifier clipping. You can often
tell how good an amplifier is at driving
complex speaker loads by looking at its
power rating into both 4
Ω and 8Ω loads.
The nearer the ratio is to 2:1 the better, as
it indicates a good current capability.
In order to reduce the effect the cable has
on the frequency response of the speaker
to inaudible levels, the impedance of the
cable at all frequencies (measuring both
positive and negative conductors in series)
should be kept as low as possible and
certainly below 0.1
Ω. At low frequencies,
the DC resistance of the cable is the
dominant factor and you should choose a
gauge of wire sufficient to achieve the
impedance requirements over the length of
cable you need to use. At mid and high
frequencies the inductive component of the
impedance can dominate the DC
resistance. This and other properties
influenced by the detailed construction of
the cable become important. Ask your
dealer for advice on the best cable for your
needs.
Aftercare
The cabinet surface usually only requires
dusting. If you wish to use an aerosol
cleaner, remove the grille first by gently
pulling it away from the cabinet. Spray onto
the cleaning cloth, not directly onto the
cabinet. The grille fabric may be cleaned
with a normal clothes brush whilst the grille
is detached from the cabinet.
The surface of the tweeter housing will
benefit from the use of an anti-static
cleaner. Do not attempt to remove the
tweeter grille.
Avoid touching the drive unit diaphragms,
especially the tweeter, as damage may
result.
Français
Garantie limitée
Cher Client,
Bienvenue à B&W.
Ce produit a été conçu et fabriqué en vertu
des normes de qualité les plus rigoureuses.
Toutefois, en cas de problème, B&W
Loudspeakers et ses distributeurs
nationaux garantissent une main d’œuvre
(exclusions possibles) et des pièces de
rechange gratuites dans tout pays desservi
par un distributeur agréé de B&W.
Cette garantie limitée est valide pour une
période de cinq ans à compter de la date
d’achat ou une période de deux ans pour
les composants électroniques, y compris
les haut-parleurs amplifiés.
Conditions
1 La garantie est limitée à la réparation
de l’équipement. Les frais de transport
ou autres, les risques associés à
l’enlèvement, au transport et à
l’installation des produits ne sont pas
couverts par cette garantie.
2 La garantie est exclusivement réservée
au propriétaire d’origine et ne peut pas
être transférée.
3 Cette garantie ne s’applique qu’aux
produits faisant l’objet de vices de
matériaux et/ou de construction au
moment de l’achat et ne sera pas
applicable dans les cas suivants :
a détériorations entraînées par une
installation, connexion ou un emballage
incorrect,
b. détériorations entraînées par un usage
autre que l’usage correct décrit dans le
manuel de l’utilisateur, la négligence,
des modifications ou l’usage de pièces
qui ne sont pas fabriquées ou agréées
par B&W,
c. détériorations entraînées par un
équipement auxiliaire défectueux ou
qui ne convient pas,
d. détériorations résultant de : accidents,
foudre, eau, chaleur, guerre, troubles
de l’ordre public ou autre cause ne
relevant pas du contrôle raisonnable de
B&W ou de ses distributeurs agréés,
e Les produits dont le numéro de série a
été modifié, effacé, éliminé ou rendu
illisible,
f. les produits qui ont été réparés ou
modifiés par une personne non
autorisée.
4 Cette garantie vient en complément à
toute obligation juridique nationale /
régionale des revendeurs ou
distributeurs nationaux et n’affecte pas
vos droits statutaires en tant que
client.
Comment faire une réclamation
en vertu de la garantie
Veuillez respecter la procédure ci-dessous,
si vous souhaitez faire une réclamation
sous garantie :
2