B&W 683 Surround Speaker System Page 2

Both the woofer/midrange in the 685 and the woofer in the HTM61 employ "conventional" Kevlar cone/butyl rubber surround design. But the two 6.5-inch woofers in the 683 are unique in that they aren't used in any other 600 series models. B&W uses what it calls a "mushroom" structure for these drivers (see photo), and their cones are composed of bonded layers of aluminum, paper, and Kevlar.

The aluminum-dome tweeter in the 600 series incorporates a tube-loading chamber similar to the type now used in many of B&W's audiophile models, but first developed for its flagship designs. The long, tapered, damped tube eliminates reflections back into the rear of the dome.

The high frequency response of this driver is also rated to 50kHz. Proof of the usefulness of response above 20kHz is thin on the ground, but the market appears to demand extended response. But if extending the response to ultrasonic frequencies pushes the inevitable resonance of a metal dome tweeter well beyond the audible range, it can't be bad.

While the 683 floor stander and 685 "bookshelf" are more or less conventional in the way they configure these drivers, the HTM61 center channel design is not. It uses a single 6.5" Kevlar cone woofer and the FST midrange positioned on either side of a single 1" tweeter, a configuration designed to eliminate (or at least minimize) the off-axis response problems that, based on our testing to date, appear to be unavoidable in two-way, horizontally-configured woofer-tweeter-woofer center channel designs.

The HTM61 is magnetically shielded but the other speakers in the system are not. In any event, magnetic fields affect only CRT displays and are no problem for any of the new digital display technologies, either flat panel or rear projection.

The ASW610 subwoofer combines 10-inch cone of Kevlar-impregnated paper and a 200W class D amplifier in a remarkably small and light package. It offers both line- and speaker-level inputs, each with its own volume adjustment. The power switch has positions for On (always on), Auto (becomes active when it senses an input and stays on for 5 minutes without an active input signal) and Standby (turns on in response to an external 12V trigger). There also are also the usual controls for phase (0/180-degrees), low-pass crossover (25-150Hz), and a switch to defeat the latter where the crossover is performed in an AV receiver or surround preamp-processor.

Less common are the ASW610's EQ (equalization) and Bass Extension switches. EQ offers two positions. A is designed to compensate for the effects of corner placement or a smaller, resonant room with excessive "bass gain." Position B is for positioning away from a corner, and/or in a less resonant room. Bass Extension offers three positions: A for the maximum bass extension, C for the least.

I set up the B&Ws in my main home theater room, a space approximately 26' x 15.5' x 8'. The 685s, used as surrounds, were positioned on 24" stands at the back of the room. The HTM61 center was placed on a B&W Nautilus center channel stand beneath the projection screen. The left and right 683s were positioned to either side of my projection screen (retracted for music listening) and toed-in toward the main listening seat. All of the front speakers were positioned 3 feet or more from the side or front walls, and except as noted all the speaker grilles were removed. I also used the full foam plugs in the ports of the 683s and the HTM61. While this rolled off the bass rapidly below about 50Hz, with an 80Hz crossover to the subwoofer this was not an issue.

The subwoofer was positioned in the front right corner of the room. I used both high pass and low pass filters set to 80Hz, with all main channel bass (including that from the floor-standing L/R speakers) directed to the subwoofer. Both the EQ and Bass Extension switches on the sub were in their "A" positions (for maximum extension plus compensation for the near-corner position). The phase switch was set to 0-degrees.

The Onkyo receiver used for the review system provides the option of Audyssey room compensation and equalization. This was not used in any of my auditions. The receiver was connected as a pre-pro to drive the front speakers through an external amp from its preamp outputs for some of the listening tests, but its onboard amps were used to drive the surrounds at all times.

Sweet Music
I set up the B&Ws directly after finishing my review of the Revel Ultima2 Studio 2 speaker package, the latter retailing for more than 10 times the cost of the 683 surround system. A pair of Studio2s alone will set you back $15,000, vs. $1,500 for two B&W 683s.

You may be thinking that I must have suffered intense withdrawal pains in the change to the B&Ws. I did not. Make no mistake, the Ultima2 setup is a stunning accomplishment. Had I the ready cash, and the ability to use the system seven days a week for 52 weeks a year (a reviewer's personal stuff gets shunted aside 90% of the time in favor of other stuff that's in-house for evaluation, and shunting the Revels aside, considering both their sound and their bulk, isn't a pretty thought), it would be at the top of my "buy in 2008" list. (I would, however, want to give a few other worthy candidates—including B&W's own 800 series—a serious spin before making up my mind about such a purchase!)

But such is the law of diminishing returns that the B&W 683 system, chump change in comparison, takes you at least 75% of the way for a fraction of the cost.

Not all of my time is spent with movie soundtracks. Listening to music in a two-channel setup is still important, and if a speaker can't do music right it doesn't matter how well it performs with anything else.

Unless noted otherwise, my music listening for this test was done with the home theater setup (including the ASW610 subwoofer crossed over at 80Hz) but using only the left and right 683s. No pseudo-surround nonsense.