Surround Sound Speaker Systems

Canton GLE 490 Floor-standing Speakers, GLE 455 Center Channel, GLE 430 Bookshelf Speakers, and AS 105 SC Subwoofer

ARTICLE INDEX

Design

The refreshed Canton GLE series was unveiled at this year's CES. Notably, Canton also announced an expanded line of reference speakers ranging from $4,000 to $17,000 a pair. While the aluminum oxide ceramic tweeters did not make their way into the GLEs, Chief Designer Frank Gobl did manage to bring a high degree of sophistication to the value line from Canton. The design approach, development tools, and modeling are shared across all of Canton's product offerings.

The GLE 4x0 series is an update to the older GLE 40x series from Canton. Not having spent time with the previous iteration, I inquired as to the major revisions in the new series. Mr. Gobl was kind enough to provide some insight into the design of the GLE series.

Canton Speakers

High on the list of improvements is a refined crossover between the mid and low-end woofers. The result is said to be a closer approximation of the Linkwitz-Riley crossover. The Linkwitz-Riley filter function has a steep 24 dB/octave rolloff at the crossover point. While the GLE uses a shallower rolloff of 12 dB/octave, the choice was made in light of the driver performance. The output of an ideal L-R crossover has zero peaking, while maintaining the drivers' radiation patterns in phase at the crossover point. The elimination of peaking (or cancellation) at the crossover, due to the summed acoustic output of drivers on-axis, maintains consistent behavior throughout the listening area for the crossover region. Even a rudimentary look at driver interaction and crossover networks shows it to be much more complex than the average listener might appreciate. The analysis extends far beyond setting the appropriate crossover frequency and applying a suitable rolloff.

A rather unique feature of the Canton line is the relative arrangement of the tweeter relative to the woofers. The majority of speaker designers opt for a straightforward tweeter, mid-woofer, woofer arrangement vertically aligned, in that order. In 3-way designs, Canton places the tweeter below the mid-woofer, and above the woofer. Canton's analysis showed a superior vertical dispersion pattern through the crossover spectrum with this arrangement. This further illustrates the extensive work Canton does to tune the crossover networks in their speaker lines.

As with many of Canton's other subwoofers, the AS 105 SC incorporates a number of design elements to improve the quality of the bass. What is referred to as SC technology is an active filter circuit intended to improve the linearity of the subwoofer. Improving the linearity and limiting the harmonics results in a cleaner and tighter bass output. More often that not, it is the upper order harmonics from grossly distorted subwoofers that is associated with boom. The other element that trickled down from the higher end units is room compensation. Two equalizer presets are available to compensate for the extent of room loading.

Cost optimization is a difficult exercise in any industry. Picking the wrong corner to cut can result in a product that might well be characterized as having more style than substance. The audio industry certainly has its fair share of offenders hiding pedestrian electronics behind thick brushed aluminum faceplates. Obviously the tradeoffs going from a $17,000 or even $4,000 speaker down below $2,000 involves certain tradeoffs. Inquiring Mr. Gobl as to what those might be, I was told cabinet construction, form factor and surface styling are the first items to be cost optimized. Give the detail to construction, and solidity of the cabinets, there certainly were no significant compromises as compared to any other product at the price point. It is apparent looking up the line that more exotic isolating feet, more extensive internal cabinet bracing, among other features, are sacrificed to meet the lower price requirement. Mr. Gobl did say that beyond a certain point some of the acoustic components are affected by cost optimizations, but was quick to also note that the magnets, cones, spiders and baskets remain substantially the same.