B&W 805S Speaker System
By Mark Fleischman
Loudspeaker technology is inherently conservative, bordering on dull. New twists have emerged over the years—surround sound, the sat/sub set, electrostats, ribbon drivers, flat panels—but most speakers are still cones and domes built into the front baffle of a rectangular box. Bor-ing!
B&W, however, has long departed from design convention, reshaping the box and realigning the drivers. Experience brings expertise, and its 805S monitor, HTM4S center and ASW825 sub are polished performers; in fact, they're eye-openingly, ear-ravishingly, soul-stirringly listenable.
But before we discuss how they sound, let's explain why a client might want to pay extra for an irregularly shaped speaker with a tube on top.
The one-inch aluminum-alloy tweeter, which hails from B&W's higher-end Signature series, is attached to a tapered aluminum tube that sits inside a plastic housing atop the speaker. It looks cool, and with big-box speakers struggling for survival in decor-conscious homes, that's an advantage when trying to win over a "sensible spouse."
Sonically, let's consider diffraction. The tweeter-on-top design prevents soundwaves from bouncing off the front baffle and corrupting the sound. B&W's explanation: "Sound waves from the tweeter [in other designs] not only radiate towards the listener but also travel along the baffle surface towards the cabinet edges. When they meet the sharp cabinet edges they re-radiate (a process known as diffraction) and, due to the time delay, interfere with and time-smear the sound coming directly from the drive unit." Raising the tweeter above the baffle avoids this problem.
The other benefit also relates to time alignment. When tweeter and woofer are built onto the front baffle surface, they're slightly misaligned. Placing the tweeter on top allows it to be moved farther back, where it aligns perfectly with the acoustic center of the woofer. Simply recessing the tweeter farther inside the baffle would also accomplish this—a lot of decent speakers work that way—but the recess itself would add cupped-hands coloration and reduce dispersion. B&W's method results in an almost startling clarity that follows you around a room.