Bowers & Wilkins CT SW Series Subwoofers

Carton Contents

Please check the subwoofer carton for the following items:

• 1 Accessory pack containing:
• 4 x M6 spike feet
• 4 x M6 rubber feet
• 4 x Lock nuts (10mm across flats)
• 1 x Two-pole Neutrik Speakon plug

The CT SW10, CT SW12, and CT SW15 subwoofers are designed for both Home Theatre installations and to augment the bass performance of 'full range' speakers in 2-channel audio systems. This manual will guide you through the process to ensure optimal performance. Keep this manual in a safe place for future reference.

Subwoofer Installation and Positioning

The CT SW Series subwoofers are intended for installation within existing or custom-designed home theatre system cabinetry, placed close to, or on, the floor.

Cabinet Installation

If installing within cabinetry, ensure the cabinet can support the subwoofer's weight and is structurally reliable. Significant vibration of cabinet panels can negatively affect the audio system's performance. Screw-in rubber feet are provided to protect the cabinet finish and reduce vibration.

Floor Installation

If installing the subwoofer free-standing on the floor, ensure it stands firmly using the supplied spike feet. The spike feet are designed to pierce carpet and rest on the floor surface. Initially, screw the lock nuts onto the spikes so they float just above the carpet when the spikes rest on the floor beneath. Screw the spikes fully into the threaded inserts at the base of the cabinet. If the cabinet rocks, unscrew the spike not touching the floor until the cabinet rests firmly without rocking. Finally, lock the nuts against the cabinet. Fitting and adjusting spike feet may be more convenient after the speaker positioning has been optimised.

Positioning Considerations

The human ear perceives low-frequency sound sources less critically than full-range speakers, making subwoofer placement generally less critical. For best results, place the subwoofer between the left and right main speakers or near one of them. If using two subwoofers, position one near the left speaker and the other near the right speaker. Placing a subwoofer behind the listening position may result in inferior imaging, but can be an acceptable compromise if domestic considerations dictate.

As with all speakers, room boundaries affect subwoofer sound. Bass volume increases with proximity to surfaces. Unlike full-range speakers, the overall system balance can be corrected by adjusting the subwoofer's volume level. However, placing subwoofers near corners can generate more low-frequency room resonances, leading to uneven bass response. Experimentation is recommended, as all rooms behave differently. Use music with ascending or descending bass lines to assess bass response smoothness, listening for exaggerated or quiet notes.

Using Multiple Subwoofers

Using multiple subwoofers can improve performance by:

• Maintaining stereo separation down to the lowest frequencies.
• Smoothing out the effects of low-frequency room resonances.
• Enabling a higher maximum sound output.

In a 2-channel system, stereo separation improves if each channel has its own subwoofer located close to its appropriate satellite speaker.

Stray Magnetic Fields

The subwoofer drive units create stray magnetic fields extending beyond the cabinet. Keep magnetically sensitive items (CRT televisions, computer screens, computer discs, audio/video tapes, swipe cards, etc.) at least 0.5m (20 inches) away from the speaker. LCD and plasma screens are not affected by magnetic fields.

Grilles

The CT SW Series subwoofers are fitted with magnetically attached fabric grilles that can be removed if desired. Take care not to damage the drive units when removing or replacing the grilles.

Connecting the Subwoofer

Ensure all equipment is switched off before making connections.

The CT SW10, 12, and 15 feature a pair of binding post connection terminals and a Neutrik Speakon socket on their rear panels. Binding posts offer quick and easy connection of stripped wires, while Speakon sockets provide a more secure and reliable connection method.

Using Binding Posts

Connect the positive cable to the red terminal and the negative cable to the black terminal. Incorrect connection can result in poor imaging and loss of bass. Refer to Figure 1 for illustration.

Using Speakon Connectors

If using the Speakon option, disassemble the Speakon plug as shown in Figure 2. Connect the speaker's '+' terminal to the amplifier's right channel (R) '+' terminal. Connect the speaker's '-' terminal to the amplifier's left channel (L) '-' terminal. For a bridged pair of speakers, the terminals are marked 1- and 2+.

In bridge mode, both amplifiers in the zone combine to create a mono output with double the power. Once the plug is reassembled, insert it into the socket and lock by twisting clockwise.

Consult your dealer for advice on selecting speaker cable. Keep its total impedance below the maximum recommended in the speaker specification and use a low-inductance cable.

Running-in Period

The speaker's performance will subtly change during the initial listening period. If stored in a cold environment, damping compounds and suspension materials will take time to recover their mechanical properties. Drive unit suspensions will also loosen up during the first hours of use. The time required for the speaker to reach its intended performance varies with prior storage conditions and usage. As a guide, allow up to a week for temperature effects to stabilise and 15 hours of average use for mechanical parts to attain their design characteristics.

Longer run-in periods (up to a month) have been reported, often attributed to the listener adapting to the new sound. For highly revealing speakers like these, the increased detail may initially sound 'up front' or hard, but will mellow over time without losing clarity and detail.

Aftercare

Cabinet surfaces typically only require dusting. For cleaning, remove the grille by gently pulling it away from the cabinet. Spray cleaner onto the cloth, not directly onto the product. Test on a small area first, as some cleaners may damage surfaces. Avoid abrasive, acid, alkali, or anti-bacterial products. Do not use cleaning agents on the drive units. The grille fabric can be cleaned with a normal clothes brush while detached.

Do not use the subwoofer as a table, as objects placed on it may rattle. Avoid spilling liquids onto the subwoofer.

If the system is to be unused for an extended period, disconnect the subwoofer amplifier from the mains supply.

Neutrik® and Neutrik® product names are trademarks and/or service marks of Neutrik®.

Diagram Descriptions

Figure 1: Wiring Diagram

Illustrates two wiring configurations for connecting the subwoofer to an amplifier in "Subwoofer (bridge tied-load) Mode". The first shows binding post connections (positive to red, negative to black). The second shows a Neutrik Speakon connector (NL4FX 4-pole) with terminals 1-, 1+, and 2+ connecting to the amplifier.

Figure 2: Speakon Connection Detail

Details the Speakon connection. It shows a Neutrik Speakon connector (NL2FX 2-pole) and NL4FX (4-pole) connecting to the amplifier. The wiring connects the speaker's '+' terminal to the amplifier's right channel (R) '+' terminal, and the speaker's '-' terminal to the amplifier's left channel (L) '-' terminal. Terminals for a bridged pair are marked 1- and 2+.