Say 'Bowers & Wilkins' to non-audiophiles and they might assume you mean BMW, but to audiophiles B&W is one of the most well-known loudspeaker manufacturers on the planet. The company was founded in 1966 by John Bowers and Peter Hayward, and today its speakers are found in more AV systems than any other brand in the world.
Taking advantage of trickle-down technology from the firm's higher ranges, the 684 uses a pair of 6.5-inch woven Kevlar cone bass/bass-midrange drivers and a Nautilus tube loaded aluminium tweeter in a curved enclosure shaped like a golf ball. This helps create an open presence that's able to reveal subtle musical details and sounds smooth, clear and coherent at all volume levels.
The 684's reworked bass/midrange driver chassis has been made smaller and the two Kevlar cone drivers have been given smaller voice coils to increase sensitivity. B&W's Anti-Resonance Plugs have also been included, a technology that eliminates unwanted vibrations in the voice coil and smoothes response.
A small but noticeable downside to the 684 is that it lacks the kind of dynamic impact you can expect from a speaker at this price. This is most obvious when listening to rock music, where the top end can sound a little hard and abrasive at high volumes. Whether this is related to the slight upper treble peak that showed up in our room measurements or not, we're not sure but it's certainly something to bear in mind when considering this model.