Karat DC 2 Speaker Components
The Karat Reference 2 DC speakers were equipped with a 1" bi-metal tweeter, two aluminum cone mid-ranges, one 12" cellulose woofer and one passive bass reflex system all combined with an enormous and sophisticated 16-lb crossover. Canton stated that all of the drivers used in the Karat Reference 2 DC (and all their speakers for that matter) were designed and manufactured exclusively by Canton .
Tweeter Chamber - Note the potting material around wire.
Canton used a modified version of their lauded 1-inch aluminum-manganese dome tweeter in a D'Appolito style configuration. This tweeter featured the company's signature one-piece dome and voice-coil former which was said to offer improved linear coupling and heat dispersion. When we interviewed Frank Gobl (head of research and development) during CES, we asked what he thought was the reason for the stellar performance of their metal dome tweeter. Having a personal preference for soft dome tweeters based on my experience with the Scan Speak models (as well as others), it was a treat to hear a metal dome tweeter which sounded natural and detailed without being bright or harsh. Frank told us the reasons for the improved performance of the Canton designed tweeter are several. Firstly, Canton implemented two distinct metals in the dome, aluminum and manganese, in order to minimize detrimental resonant frequencies which can occur from single metal domes. In addition, Frank informed us that unlike soft dome tweeters, a metal dome design could be shaped and molded into specific patterns that prevented ringing while providing a predictable and accurate frequency response. What ever the reason, this metal dome tweeter made a believer out of me.
To further improve the performance of the tweeter, Canton isolated the tweeter in a separate chamber. The wires which passed through the chamber were potted into place filling the hole and thereby totally isolating the tweeter.
Two 180-mm (7") aluminum cone drivers with a 1" voice coils created
the mid-range section of the Karat Reference 2 DC speakers. What struck
us as odd upon examining these mid-range drivers was the fact that they
baskets were made from a polycarbonate, not cast aluminum or magnesium
which tend to be more common.
Furthermore, the webs of the basket were spread out far apart with only
4 in total.
Other aluminum dome drivers with cast aluminum frames this size
typically have at least 6 webs.
We pondered on this for a bit and then asked Frank Gobl the reasoning
behind such a design. Frank told us that the baskets were made from
with 20% glass pellets
which he stated was more inert and stiffer than metal. He also
explained that by using this material, it ensured that the major
resonance behavior was well outside the used frequency range of each
He added that you can literally stand on the basket and not be
concerned over it breaking or crumbling.
But even so, we couldn't help but wonder what the Karat Reference 2 DC
speakers may have sounded with a more traditional driver.
Another noticeable item was the smaller sized magnet when compared to other drivers of this size. Once again, Canton points out that there is rhyme and reason. Canton implemented a high power neodymium magnet which reduced its overall size while improving internal venting. Neodymium magnet driver designs, if not properly vented, can essentially lead drivers into thermal compression. While we have heard this problem on lesser designs, it didn't seem to be an issue with the Karat 2 DC.
The Bass Reflex System
To Port or not to Port? - That is the question.
Canton utilized a passive radiator design on the Karat Reference 2 DC speakers. In the past, I have not been an advocated of this solution as many of the mass produced speaker companies tended to use this only to show more driver space. But Canton once again has made a believer out of me. During our meeting with Frank Gobl, we asked him to comment on Canton 's design and the radiators ability to produce such deep, tight and accurate bass. Frank told us that they did not just implement a passive radiator; they created a bass response system. He went on to explain that port noise is very common with many ported cabinet designs. Furthermore, in order to prevent port noise, it's important to tune the cabinet below the audible range, which is below 20-Hz, as well as below the resonance frequency of the driver, which in this case, was 10-Hz. In order to do this, the port size became so large that it would have resulted in an increased cabinet size which would in turn ripple into a list of other issues. Frank told us that the Canton solution to this design challenge was to create a passive radiator that acted as more than a bass reflex system. It also tuned the cabinet below 10-Hz thereby eliminating port noise and resonance. The result is the deepest, most natural bass I've heard from a non-powered loudspeaker.
External View of Passive Radiator
Internal View of Passive Radiator
Woofer Bass Driver
What passive radiator design would be complete without a woofer to drive it? In this case, the Canton Karat Reference 2 DC speaker implemented a 310-mm (12") cellulose graphite material woofer.
Unlike the mid-ranges, the basket for the woofer was cast-magnesium with 6 webs thereby adding to the weight and robustness of this massive driver. Frank explained that the magnesium basket was much stiffer than a cast aluminum design and that the resonance was much lower than the low frequency response of the woofer, thereby improving the bass handling of this driver. For the record, magnesium is 1/3 lighter than aluminum and is a silvery-white, and fairly tough metal that ignites upon heating over 500 degrees in air. There aren't too many manufacturers that use magnesium due to the hazards involved during casting and machining, both of which are heat related processes.
The Crossover Electronics
Upon examining the cabinet, Gene and I couldn't help but wondered what was behind the 12 screws that mounted a rather large back plate. So we began the unscrewing process thereby revealing what was probably the largest crossover electronics we've ever cast our eyes upon.
The massive 16 pound 3-way crossover network featured quality components such as ICW capacitors, hand-wounded coils, and it was mounted in its own decoupled hermetically sealed chamber providing optimal microphonic isolation from the speaker's mechanical and acoustical parts. The crossover also included Linkwizt filters to combine 12-dB/octave electrical filter with 12-dB/octave acoustic filtering for a 24-db/octave roll-off. Fast Audio 6M cabling was soldered to each speaker with twisted triples extended to all drivers.
We asked Frank Gobl how Canton can incorporate such a vast array of electronics while minimizing insertion loss. Frank assured us that their design and build quality was such that insertion loss was minimized and not an issue.