Despite their reasonable price points, the 600 series is filled with truly advanced features. The aluminum dome tweeters are mounted in an oval-shaped alloy plate, which gives all the speakers in the series a distinctive look when their grilles are removed. The tweeter assembly uses trickle-down technology from the unbelievable, cost-no-object Nautilus series of speakers, tube loading, Neodymium magnets and a first-order filter. While all of the 600 series feature Kevlar midrange drivers, the 683s feature B&W's FST (fixed suspension transducer), previously only available in the high-end B&W series. The FST technology places a ring of foam with mechanical properties matching that of the driver in the place of a traditional surround to reduce distortion of the cone face. The bass drivers are a paper/Kevlar mix, with an aluminum skin. Bass is supplemented with the Flowport. The Flowport has been used in other B&W speakers and is simply described as a port with golf ball-type dimples to reduce port noise. A rubberized, soft touch material is placed on the front side of the cabinets. This, coupled with the elimination of visible screws around the drivers, makes for a very attractive package. The rest of the cabinet is finished in a choice of four vinyl veneers, with the floor standers resting on black plinths, which are both attractive and functional, as they add stability. The 683's 57-pound cabinet is 38.8 inches tall, 7.8 inches wide, 13.4 4 inches deep and houses four drivers, a one-inch tweeter, a six-inch midrange and a pair of six-and-a-half-inch woofers in a three-way configuration. Frequency response is 38Hz to 22kHz, with a sensitivity rating of 90 dB. The HTM61 is the larger of the two center-channel options at 7.8 inches high, 21.5 inches wide and 13.4 inches deep. Frequency response and sensitivity match that of the 683s.
The new 600 Series sounds more refined than its predecessors. I was particularly impressed by the 683's neutrality. The midrange did a good job with both female and male vocals. The highs, while perhaps just a bit forward, were clean, extended and should compete favorably with most options in this price range. The soundstage was open and deep, with relatively solid placement of the individual sources. With R&B or pipe organ concertos, the 683s benefit from the use of a subwoofer to handle the lowest frequencies, but are clean and detailed within the bounds of their response curve. The HTM61 was a capable performer, but I did not feel that it was up to the same performance level as the 683s. I was able to give the 685s, the larger of the two bookshelf speakers, a listen at a local retailer and would consider trying one of them in center position.