Canton Karat Reference 2 DC Speakers Review

Canton uses computer simulations and FEA models, along with CAD software to design their speakers. After the basic design is completed, they build a full prototype which is then immediately placed in an anechoic chamber for testing and verification. The prototypes and production speakers are all assembled by hand and immediately checked against the specifications from the reference unit.

Canton introduced the new Reference 2 DC speakers as their ultimate flagship. "We put everything into this development that is currently possible. Our team analyzed, simulated, made constructed handmade models to work out details, built prototypes and tuned the acoustics in countless auditions, until we were finally satisfied with the results. What we have achieved is a masterpiece that is the embodiment of a great deal of love and respect for detail", stated Canton 's CEO, Günther Seitz.

Some of the pictures in this article were provided by Canton and can also be found in their marketing literature. They were meant to provide accurate representation of the Canton Karat Reference 2 DC design. The Canton pictures were paired with our own pictures to enhance this article by providing as much detail and information as possible. Their pictures showed the internal chambering of the cabinet and exploded isometrics of the drivers which would normally be impossible to provide on our own. We hope you enjoy the unique visual representation of these speakers.

With such a mighty, well constructed cabinet, we pondered on an internal feature. Canton did not panel the internal sides of the cabinet with dampening panels which was found in many other speakers we reviewed. While the standing wave from the trapezoid cabinet design may indeed be reduced, there are still internal reflections that occur. The question is, how detrimental to performance are these reflections? Many speaker manufacturers, coated the internal sides of the cabinet walls with a self adhesive dampening material to absorb the side to side reflections. Canton did not implement this convention in their cabinet design, perhaps for several reasons. It's possible that the trapezoidal shape reduced detrimental reflections from interfering with the drivers as there wasn't an easy path back to the driver as in a boxy designed cabinet. In addition, the cabinet was constructed of two different densities of material including a High Density and Medium Density. While this reduced cabinet resonance, it may also have helped absorb some of the potentially detrimental reflections. What ever the case, I'm reasonably sure Canton thought of this prior to constructing such a rugged, sturdy well engineered cabinet.

The cabinet was constructed from 1 ¼" thick multilayer HDF and MDF and coated in satin silver lacquer which Canton indicated that this was a tedious manufacturing process. This silver lacquer made Reference 2 DC seem surreal.

Without question, the Canton Karat Reference 2 DC cabinet was one of the best built cabinets I've seen thus far in a speaker at or under $10k. From the bracing to the coating and finish, it's easy to see how technically solid and difficult this cabinet was to build.

Perhaps due to our engineering background which makes us wonder how everything works, or our general curiosity, combined with our desire to create a complete review, we took the liberty of dissecting the Karat Reference 2 DC by removing the drivers. It was only after the fact that we asked forgiveness from the Manufacturer, who was gracious in their response. Given their price, I proceeded with much caution, and enthusiasm. Upon removing all the drivers, I began my thorough examination of the foam and internal bracing.

The internal structure was a vast array of bracing and baffles creating five chambers all designed to dampen and stiffen the cabinet as well as reducing standing waves.

To me, nothing is more annoying than opening a pair of speakers, moving them into position, and then having to install spikes, especially when they weight almost 140-lbs each. What's equally annoying is trying to find coins, or some other sufficient item, to wedge beneath the spikes so they do not scratch, dent or mare the tile/hardwood floor. For those who share this dislike, Canton has provided the solution. The cabinets for the Karat Reference 2 DC are equipped with built in floor plates and shock absorbers making the installation of these speakers nothing more then locating them, and plugging them in. No spikes, no coins, no scratches, no balancing, just simply drop, plug and play. The base plate and shock absorbers provided sufficient decoupling of the speaker to the floor, thereby possibly potentially improving the performance of the speaker.

One very unique feature of the Canton design was that there were no visible mounting holes for the grill covers. Canton cleverly implemented the holes in the mounting flange of the mid-range to make them non obtrusive for those "nudists" who prefer to go grill-less.

Another redeeming quality incorporated in the design was regarding Canton's method for mounting the drivers. Instead of using wood screws in the MDF material, Canton incorporated metal insert fasteners for all drivers and secured them with machine screws. This was especially useful for us when we removed the drivers and installed them back in place as we didn't have to worry about the MDF threads stripping. The foam gasket behind the drivers was a light weight, thin foam material unlike some of the rubber gaskets we've seen in other designs. But what was probably more important and commendable was that the wiring connecting of all the drivers were soldered instead of using lugs. Canton also used twisted triple wires for the + and - connections of each driver, thereby reducing resistance between the crossover electronics and the drivers.

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 .

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 this poly-carbonate 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 driver. 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.

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.

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.

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.

 

The picture below shows the cone of the R2 midrange driver with a theoretical displacement of 5mm at around 1kHz . Of course it is impossible to produce a displacement of 5mm at 1kHz with a real driver, but it shows impressive the behavior of the cone.

Theoretical Displacement R2 Midrange Driver Cone
The next two pictures are from our simulation software "OERSTED" from IES. The pictures show the B-field of a standard motor in comparison to the motor of the Reference 2. Two screenshots show the magnetic field within the air gap and the other two shows the magnetic flow within the material.