Room-filling sound without a room-filling speaker cabinet. Slimmer than ever before, the 684 S2 offers an amazing combination of floorstander power, audio performance and unbeatable value.
Switching to 5-inch bass/midrange drivers from the previous 6.5-inch cones, means the 684 S2 is now significantly slimmer than its predecessor, with simultaneously improved audio performance, thanks to Bowers & Wilkins innovation. The two Kevlar cone drivers benefit from smaller voice coils to increase sensitivity.
The 5-inch drivers now also feature Anti-Resonance Plug dustcaps, technology taken from our high-end PM1 speakers, that improve pistonic movement inside the voice coil. This helps to deliver amazingly distortion-free midrange performance, all in a smaller space.
As well as slimmer, improved driver performance, the 684 S2 also features a Decoupled Double Dome tweeter. Double dome technology, brought across from the CM10, increases tweeter rigidity for a more precise sound, while the tweeter sits in a gel-filled cavity, decoupled from the surrounding cabinet - which removes resonances and vibrations, for a more natural, spacious sound.
Not all sound is good. Sound from the rear of a driver or tweeter can bounce around a cabinet and undermine the good sound coming from the front. Nautilus Tapering Tubes, filled with absorbent wadding, reduce unwanted sound to a minimum.
Preventing cabinet vibrations reaching the tweeter leads to cleaner, sweeter high-frequency performance. Synthetic gel cushions a Decoupled tweeter, with the assembly isolated from the mounting. The result is a more natural, spacious sound.
The same properties that let Kevlar stop a bullet also make it ideal for soaking up standing waves in a speaker cone, so they don't colour midrange sound. That's why our midrange cones have been made with Kevlar since 1974. It delivers a cleaner sound, to a wider group of listeners. The new 600 Series continues this trend.
'Fixed Suspension Transducer' Kevlar cones are mounted in a narrow ring of foam. This 'surroundless' suspension minimises distortion by converting unwanted energy into heat, not sound. The result is the cleanest midrange around.
Unlike most dust caps, these mushroom-shaped devices - first seen in the PM1, and now in the 600 Series - fit tightly inside the voice coil bobbins. This ensures better pistonic movement, reducing higher-frequency break-up for a superior performance.
In the 600 Series, both the 683 and HTM61 speakers feature improved bass drivers that feature a new Dual Layer aluminium construction, similar to that of the new Double Dome tweeter. This new construction technique shifts the break-up frequency of the driver from 4kHz to 5.5kHz, ensuring a richer, distortion-free bass response and improved integration with the midrange.
The surface dimples around the 600 Series Flowport minimise turbulence by generating tiny eddy currents over which air can flow smoothly, like a golf ball. This reduces turbulence and leads to improved bass response at higher volumes.
The crossover sends the audio signal to the right driver, depending on frequency. The simpler this vital component is, the better. And the better the drivers, the simpler it can be. In the 600 Series the high-frequency crossover uses just one capacitor.
Trusted Reviews August 2014
"With wonderful sound quality, low-key design and impressive driver technology, 684 Theatre is deserving of your hard-earned cash."
Read the full review
|Nautilus Tapering Tube|
|Technical features||Decoupled Double Dome aluminium tweeter with Nautilus™ tube loading|
Kevlar® brand fibre cone bass/midrange drivers
|Description||2-way vented-box system|
|Drive units||1x ø25mm (1 in) aluminium dome high-frequency|
2x ø130mm (5 in) woven Kevlar® cone bass/
|Frequency range||-6dB at 45Hz and 50kHz|
|Frequency response||72Hz - 22kHz ±3dB on reference axis|
|Dispersion||Within 2dB of reference response|
Horizontal: over 60º arc
Vertical: over 10º arc
|Sensitivity||87dB spl (2.83V, 1m)|
|Harmonic distortion||2nd and 3rd harmonics (90dB, 1m)|
<1% 140Hz - 22kHz
<0.5% 180Hz - 20kHz
|Nominal impedance||8Ω (minimum 3.5Ω)|
|Recommended amplifier power||25W - 150W into 8Ω on unclipped programme|
|Max. recommended cable impedance||0.1Ω|
|Dimensions||Height: 920mm (36.2 in) cabinet only|
Width: 160mm (6.3 in) cabinet only
Depth: 234mm (9.2 in)
|Net weight||14.2kg (31.2 lb)|