Bowers & Wilkins ASWCM Importantes Instructions Concernant La Sécurité, All applications

2-channel audio

The optimum settings of the PHASE switch and the LOW-PASS FREQUENCY control are inter- related and also dependent on the low-frequency cut-off characteristic of the satellite speakers and the relative positions of all the speakers in the installation.

Set the system up in the preferred position and play some programme with a steady bass content. The optimum setting for the LOW-PASS FREQUENCY depends on several variables; the bass performance and power handling of the satellite speakers, the number of subwoofers used and their position relative to the satellite speakers. The range 80 – 90Hz is a good starting point for the LOW-PASS frequency. Unless two subwoofers are used to preserve separate right and left channel information and are sited close to the relevant satellite speakers, using a higher cut-off frequency may compromise the stereo image and should only be considered if the bass performance of the satellite speakers is particularly limited.

At each setting of the cut-off frequency, listen with the phase switch in both positions. The correct one is that which gives the fullest bass and that will depend on the bass characteristics of your satellite speakers and the relative distances of the subwoofer(s) and the satellite speakers to the listeners. When using more than one subwoofer, ensure that each one has its cut- off frequency and phase switch set the same way.

Set the loudness of the subwoofer relative to the satellite systems to your liking. Use a wide variety of programme material to get an average setting. One that sounds impressive on one piece may sound overpowering on another. Listen at realistic levels as the perception of balance varies with sound level.

Home theatre

The situation with home theatre is somewhat different from 2-channel audio. The subwoofer (LFE) signal is a separate channel rather than an extension of the signal to the satellite speakers. The LOW-PASS filter is switched out, because the decoder provides all the filtering for any speakers set to “small”. However, the position of the phase switch must still be assessed. Normally the phase will be set to 0˚, but if the subwoofer is positioned at a distance significantly different from the other speakers, or the power amplifier driving the other speakers happens to invert the signal, the 180˚ position may be preferable. Listen with the switch in both positions and choose the one that gives the fullest sound. If there is little difference, leave the switch at 0˚.

Decoders normally have a calibrated noise signal that can be used to set the relative levels of all the speakers, making the task somewhat more straightforward than for 2-channel audio. However, do not be afraid to alter the settings to your personal preference. It is all too easy to get carried away with the capabilities of the subwoofer, especially with some special low-

frequency effects. Often a more realistic portrayal, and one more satisfying in the long term, is to be had by setting the subwoofer level lower that the standard calibration level.

All applications

If you get problems with lumpy bass – if certain bass notes are exaggerated more than others – then you probably have a room interface problem and it is worth experimenting with the placement of the subwoofer. What may seem like small changes in position – 15cm (6in) or so

–can have a profound effect on the sound. Try raising the subwoofer clear of the floor as well as lateral movement. The use of multiple subwoofers can smooth the effects of room resonances, as each subwoofer will tend to excite resonances at different frequencies. If you alter the relative distances from the subwoofer(s) and satellite speakers to the listeners appreciably, reassess the phase switch setting. You should also check the level setting of the subwoofer (using either the decoder output levels or the volume control on the subwoofer amplifier as appropriate), but only after setting the phase correctly.

Taking care of the subwoofer

Do not use the subwoofer as a table. When in use, objects left on top of the subwoofer are liable to rattle. In particular, avoid the risk of liquids being spilled (eg from drinks or vases of flowers).

If the system is taken out of use for a long period, disconnect the subwoofer from the power supply.

Note: The subwoofer will automatically shut down if driven excessively. If this occurs, re-set the subwoofer by turning it off then on again, using the power on/off switch on the amplifier panel.

FRANÇAIS

IMPORTANTES INSTRUCTIONS CONCERNANT LA SÉCURITÉ

ATTENTION

RISQUE D’ÉLECTROCUTION

NE PAS OUVRIR

Attention :

Pour réduire le risque d’électrocution, ne pas démonter le panneau arrière et ne pas exposer l’appareil à l’humidité ou à la pluie. Il n’y a aucun élément susceptible d’être modifié par l’utilisateur à l’intérieur. Adressez-vous toujours à un technicien agréé.

Explication des symboles graphiques :

L’éclair dans un triangle équilatéral indique la présence interne de tensions électriques élevées susceptibles de présenter des risques graves d’électrocution.

Le point d’exclamation dans un triangle équilatéral indique à l’utilisateur la présence de conseils et d’informations importantes dans le manuel d’utilisation accompagnant l’appareil. Leur lecture est impérative.

PRÉCAUTIONS IMPORTANTES :

1Lisez ce manuel d’utilisation – Tous les conseils de sécurité et de fonctionnement doivent être attentivement lus avant de faire fonctionner l’appareil.

2Conservez ce manuel – Vous devez pouvoir vous y référer dans le futur, notamment pour les instructions concernant la sécurité.

3Suivez les recommandations – Toutes les recommandations concernant la sécurité durant le fonctionnement doivent être rigoureusement suivies.

4Suivez les instructions de fonctionnement – Veuillez exclusivement vous conformer aux instructions qui suivent, concernant l’utilisation et les réglages de cet appareil.

5Installation – Veuillez respecter les consignes données par le constructeur.

6Alimentation – Cet appareil doit exclusivement être alimenté suivant les caractéristiques (tension, fréquence du secteur) indiquées sur l’étiquette collée en face arrière. En cas de doute, consultez immédiatement votre revendeur.

7Mise à la terre ou en phase – Cet appareil ne nécessite pas de mise à la terre.

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