B & W DS7 Surround Speakers

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, 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, which makes for a more naturally diffuse sound field.

DS7 Specifications