Bowers & Wilkins DS7 2-Way Closed-Box Surround Speaker

The DS7 is specifically designed as an on-wall surround speaker for multi-channel audio and home theatre installations.

Surround speakers generally fall into two main types – those that one might describe as 'normal' speakers - so-called monopoles, where the sound comes from a set of drive units mounted on the front of the enclosure - and those that give a more diffuse sound field, such as dipoles. Each type has its advantages.

Most multi-channel music is monitored using monopole surround speakers, whatever the multi-channel recording format. This enables better location of side and rear images, although the formation of such images is never quite as precise as it is between the front speakers.

Most films are originally balanced for cinemas, where a large number of speakers spread around the auditorium are used to create a surround sound field that gives an all-enveloping effect. Dipoles are better at recreating this type of sound field in the home, but using fewer speakers to do it, and they make the installation easier to balance for a larger listening area.

The DS7 offers a choice of both monopole and dipole operation, either via a switch located on the front baffle, or remotely, using a 12V trigger from the surround processor. Some processors allow you to program the 12V trigger according to the type of material being played, so you can automatically switch between the two modes if desired.

In monopole mode, only the two drive units on the front face operate. In dipole mode, the front tweeter is disconnected; the two side firing drivers are brought into operation and the crossover frequency to the bass unit is lowered. The side units are connected out of phase with one another, which creates a wedge-shaped null zone at right angles to the wall. If the listeners sit within this zone, they become less aware of the location of the speakers and hear more reflected sound; hence the diffuse nature of the sound field.

Technical Specifications : DS7
Description	2-way closed-box selectable dipole/monopole surround system
Dimensions	Height: 302mm (11.9 in) Width: 383mm (15.1 in) Depth: 165mm (6.5 in)
Net Weight	8.5kg (19 lb)
Freq. Response	80Hz – 22kHz ±3dB on reference axis (monopole mode) 80Hz – 10kHz ±3dB power averaged over front hemisphere (dipole mode)
Freq. Range	-6dB at 60Hz and 42kHz (monopole mode) -6dB at 60Hz and 15kHz (dipole mode)
Sensitivity	89dB spl (2.83V, 1m)
Normal Impedance	8Ω (minimum 3.0Ω)
Power Handling	25W – 120W into 8Ω on unclipped programme 12V trigger current requirement 45mA
Drive Units	Unit 1: ø165mm (6.5 in) woven Kevlar® cone bass/midrange Unit 2: 2x ø100mm (4 in) midrange/high frequency Unit 3: ø25mm (1 in) alloy dome high-frequency
Finish	Cabinet: Black or white paint Grille: Black or white cloth
Dispersion	Description: Dipole mode: horizontal figure of eight Effective null zone ±30º (250Hz – 15kHz) Monopole mode: within 2dB of reference response Horizontal: over 40º arc Vertical: over 10º arc
Harmonic Distortion	2nd and 3rd harmonics (90dB, 1m) <1%110Hz – 20kHz
Crossover Frequency	250Hz (dipole mode) 4kHz (monopole mode)
Max. Recommended Cable Impedance	0.1Ω

(Quantity: Select 2 for pair)