Bowers & Wilkins owner manual 2800D, 3DS8S, Fine Tuning

The ear is at its most sensitive in the midrange, so we recommend that, when single wiring, you connect the cable from the amplifier to the terminals that directly feed the midrange driver.

Bi-amplification goes a stage further and involves the use of two separate power amplifier channels for each speaker. It is not the same as having a fully active system, because the speaker's internal passive crossover is still used.

If using bi-amplification, ensure that each amplifier channel has the same gain, otherwise you will change the balance of the speaker. Check the absolute polarity. Some amplifiers invert the signal, and a mixture of different types may cause a dip in the overall response. If you have a mixture of inverting and non-inverting amplifiers, reverse the polarity of the connections from any inverting amplifier to the speaker.

Bear in mind that, even though midrange and, even more so, tweeter drivers can (and only need to) handle less continuous power than bass drivers, the amplifier feeding them needs to have an adequate voltage swing in order to supply the short-term high-frequency peaks in music without distortion. A high voltage capability implies high power, so it is not particularly desirable to have a lower powered amplifier feeding the midrange and tweeter than is used for bass drivers.

Model f Go to

800D4.2

All other models (not DS8S) Continue

On delivery, the two pairs of terminals are electrically separate from one another ready for bi-wiring. (figure 32)

For single wiring, short cables are provided to link both positive and both negative terminals together. Each cable carries a spade connector at one end and a 4mm banana plug at the other.

When single wiring, connect the cable from the amplifier to the lower terminals on 2-way systems (805S, HTM4S, SCMS) and the upper terminals on 3-way systems.

On these terminals, use the opposite type of connector on the link cables to what you have terminating your main cable. For example, if your main cable terminates in spade connectors or bare wires, use the banana plug end of the link cables in the same terminals. (figure 33)

fGo to section 5.

4.2800D

On delivery, both positive and both negative terminals are connected together by link plates.

When single wiring, leave these links in position and connect the cable from the amplifier to the centremost pair of terminals. (figure 34)

When bi-wiring or bi-amplifying, remove the links after loosening the lower, larger diameter terminal caps. (figure 35)

The 4mm hole in the end of the terminal post features a collet that may be tightened around a banana plug using the upper, smaller diameter terminal cap.

fGo to section 5.

4.3DS8S

In addition to the normal speaker terminals, there is an additional pair of screw terminals to operate an internal 12V relay that switches the speaker between monopole and dipole modes from a remote trigger. (figure 36)

You cannot use this facility if:

aYour processor does not feature a 12V trigger at all.

bYour processor only offers a simple trigger that outputs a 12V signal when the unit is switched on. This can only be used to switch other equipment on and off at the same time.

Some of the most expensive processors allow you to assign a trigger to the type of programme being played. They recognise information on the disc that distinguishes between movies and multi- channel music. Others allow you to assign triggers to different inputs; so if, for example, you use a multi-channel SACD or DVD-A player for music and a separate DVD player for movies, you can set up a trigger accordingly.

The relay in the speaker needs a certain amount of current to operate, so check the specification of your processor first before proceeding. You will need to draw 45mA for each speaker you want to switch.

The relay in the speaker only works when the manual switch is set to the monopole

(•)position. If there is no voltage to the trigger input, the speaker stays monopole. If a 12V DC signal is present, the relay overrides the manual monopole setting and switches the speaker to dipole mode. If you have the switch set to the dipole (••) position, the trigger feature will not work.

fContinue to section 5.

5 FINE TUNING

Before fine tuning, double check that all the connections in the installation are correct and secure.

Floor- and stand-mount speakers only

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.

803D, 803S, 804S, 805S, HTM1D, HTM2D, HTM4S, SCMS only

These vented-box systems are supplied with foam plugs fitted in the ports. Normally, the speakers should be used with these plugs removed for maximum bass output, but if the bass is too heavy due to room effects and you cannot move the speakers further from the walls, refit the plugs to reduce the bass output. (figure 37)

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 positioning the speakers along a different wall. Even moving large pieces of furniture can have an effect.

For the most discerning listening, remove bass and midrange grilles as described in section 8 – Aftercare.

Tweeter diaphragms are very

delicate and easily damaged. The tweeter grilles are held in place with magnetism and any mishandling of the grille close to the tweeter may result in the grille being attracted into the tweeter diaphragm. For these reasons, we recommend that you leave tweeter grilles in place.

800D, 801D, 802D, HTM1D only

If you use these systems without the midrange grille, replace the plastic centre plug of the midrange drive unit with the solid aluminium plug in the accessory pack. Simply unscrew the fitted plug and screw in the replacement. Hand tighten only. (figure 38)

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.

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