Bowers & Wilkins 600 Series Loudspeakers Preview

Bowers & Wilkins is a company that needs little introduction. With a history dating back to the 1960’s, and speakers in illustrious studios like Abbey Road and Skywalker Ranch, most audiophiles are at least  somewhat familiar with the name, as well as their bread and butter 600 series. However, not content to let the 600 series stagnate, B&W has refreshed their entry level lineup, bringing some trickle down technology and one new trick to help boost performance. An evolution rather than a revolution, we’ll examine what B&W is bringing to the table with their new lineup.

What’s New?

Suffice it to say, B&W’s new 600 series offers a mouthful of technology to discuss, the first being their Decoupled Double Dome Tweeter from the CM10. The “Double Dome” utilizes two layers of aluminum for the diaphragm: a standard aluminum dome and a second layer with the center cut out and glued to the rear of the first. B&W claims this significantly increases the rigidity of the diaphragm, and notes that the first breakup frequency of the new tweeter is well beyond human audibility at 38kHz. Also as one might imply from the name, the tweeter assembly is decoupled from the cabinet via a gel ring to keep unwanted resonances from interfering with the tweeter.

Exploded view of B&W’s Decoupled Double Dome tweeter. The added metal screen covering is a nice touch to keep little fingers out.

The next piece of technology to trickle down is B&W’s Anti-Resonance Plugs for their Kevlar mid/woofer units, brought down from the PM1. Ostensibly a mushroom shaped dust cap, the “stalk” of the plug extends tightly down tightly the voice coil former. As a result, B&W states their mid/woofers should achieve a smoother response at the top of their passband, and ultimately a more detailed and refined sound.

Last but not least for the 600 series, B&W is rolling out all new Dual Layer aluminum bass drivers. Like the “Double Dome” tweeters, these woofers consist of a layer of aluminum which is then reinforced at the edges with a second layer. Again, the end result is improved rigidity to push cone breakup further away from the driver’s operating band, which is particularly important given the low order slopes used in B&W’s minimalist crossovers.

The Speakers

Along with their technical improvements, B&W has six new models to talk about. At the top of the heap is the new and improved 683, a 3-way floorstanding speaker featuring the new 1” dome tweeter, B&W’s familiar 6” FST midrange driver, and dual 6.5” aluminum woofers. Priced at $1,650 a pair, the 683’s offer a frequency response of 52Hz-22kHz (+/-3dB), along with an average sensitivity rating of 89dB with 2.83V at 1 meter, and an 8 ohm nominal impedance (3 ohms minimum). It should be noted due to the minimum impedance that you will want to pair the 683 with an amplifier stable into a 4 ohm load.

Old (left) vs new (right), the B&W 683. The refreshed 600 series features a slimmer profile to improve SAF (Spouse Acceptance Factor).

Moving down the line, we run into the 684, a 2-way floorstanding model priced at $1,150 a pair, and boasting dual 5” mid/woofers along with a 1” tweeter. Frequency response is rated from 72Hz-22kHz (+/-3dB), indicating that you’d need to pair the 684 with a subwoofer to get meaningful low end response. The 87dB sensitivity and 4 ohm minimum impedance (8 ohm nominal) again suggest that the 684 would be best utilized with an amplifier rated down to 4 ohms.

Looking at the bookshelf models, B&W offers the 685, which boasts a 6.5” mid/woofer and will set you back $700 a pair, as well as the 686, which makes do with a 5” mid/woofer and is priced at $550 a pair. The 685 and 686 are rated down to 52Hz and 62Hz (-3dB) respectively; depending on your tastes, a subwoofer may be necessary to help fill in the low end, though the 685 may be sufficient to satisfy many listeners on its own. In terms of sensitivity, the 686 again has the advantage, delivering 87dB with 2.83V at 1 meter, versus 85dB for the 685; however, with a minimum impedance of 4 ohms versus 5.2 ohms for the 686, it may not be much (if any) easier of a load for a partnering amplifier.

Finally, we get to B&W’s surround sound offerings, namely two center channels, the HTM61 and HTM62. Priced at $750 apiece, the HTM61 is a full-fledged 3-way design boasting a 1” tweeter, 4” FST midrange, and dual 6.5” aluminum woofers. With a frequency response of 50Hz-22kHz, sensitivity of 88dB, and a minimum impedance of 5.2ohms, it looks like it shouldn’t have any trouble keeping up with the 683 tower. On the other hand, the HTM62 is a simple two way design sporting a pair of 5” mid/woofers and costs $450 per speaker. Frequency response is rated from 70Hz-22kHz (+/-3dB), with a sensitivity of 87dB and a nominal impedance of 8 ohms (5.2 ohm minimum). Worth noting, horizontal dispersion of both models appears to leave something to be desired. While on the vertical plane, both speakers achieve a response within 2dB of the on axis response over a wide 60 degree arc, on the horizontal plane, that window is achieved only through relatively narrow 20 degree arc.

Summary

While it’s unlikely that B&W’s new 600 series will create a revolution in the loudspeaker market, it’s nonetheless nice to see the product line evolve. Stiffer woofers and tweeters that push cone breakup further up the frequency range are always a good thing, particularly in the case of the woofers when used with B&W’s typical minimalist crossover networks. In addition, the slimmed down look improves the aesthetic appeal considerably, making it more likely for your wife/significant other to approve. Overall, it looks like the new 600 series is a worthy successor to the old. Now, we’d just like to get our hands on a pair or two for further evaluation…

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.