ELECTRONICALLY REPRINTED FROM JANUARY 2003

CANTONS KARAT

A Reference $10K Speaker

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espite my 26 years in audio journalism, the amount of stuff I need to know seems to increase faster than I can cope with it. Thus it didnt come as too much of a surprise for me to learn that speaker manufacturer Canton, the Teutonic equivalent of Englands B&W, a) was 30 years old in 2002, and b) claims the dominant market share of the German market. Yes, Id been peripherally aware of Canton through the years, but for various reasons had never auditioned any of their models. I was amenable, therefore, when Canton USAs Paul Madsen suggested to me last May, at Home Entertainment 2002 in New York City, that I review their flagship speaker. The Karat Reference 2 DC yes, that name will never trip off the tongue was introduced to celebrate Cantons 30th anniversary and is the result of the companys design team, headed by Frank Gbl, in effect being given free rein to design both the drive-units and the system that would use them. With its metallic-silver lacquer finish (alder and beech veneers are also available), the Reference 2 DC is a handsome speaker standing some 4' tall. Despite its mass and bulk, it doesnt visually dominate a room, because only the upper-frequency drivers are mounted on the enclosures narrow face. The
12" woofer and Auxiliary Bass Radiator (ABR) are mounted opposite each other on the large sidewalls. I first saw this idea on the Acoustic Research AR9 from two decades ago, and it resurfaced in the early 1990s on the AudioPhysic Virgo. Not only does it allow the speaker to have a slim frontal profile, which benefits upper-frequency dispersion; it also ensures that the cabinets largest panels, whose vibrations are the most difficult to control but which couple most efficiently to the air, are facing away from the listener. Even so, the Karat References trapezoidal enclosure has been heavily braced and reinforced to minimize panel vibrations, and is constructed from a laminate of two different particleboards with different densities. To minimize the effects of internal space resonances, there are no parallel internal surfaces, and the interior is divided into several different-sized vaults, according to Cantons White Paper on the design. The 2 DCs drive-units have been designed with the latest in finite-element analysis and magnetic-circuit simulation programs, to maximize linearity at large diaphragm excursions and minimize the prevalence of unwanted diaphragm breakup modes. The 1" metal-dome tweeter handles frequencies above 3.2kHz. Its low-mass dome and coil for-
Description: Three-way, ABR-loaded, magnetically shielded, floorstanding loudspeaker. Drive-units: 1" (25mm) aluminum-manganese dome tweeter, two 7" (180mm) aluminum-manganese midrange cones, 12" (310mm) graphite-loaded paper-cone woofer, 12" (310mm) flat-diaphragm Auxiliary Bass Radiator (ABR). Crossover frequencies: 150Hz and 3.2kHz, 24dB/octave acoustic slopes. Frequency range: 18Hz30kHz. Sensitivity: 89dB/2.83V/m. Nominal impedance: 8 ohms (4 ohms minimum). Recommended power: up to 350Wpc. Dimensions: 47.2" (1200mm) H by
11.8" (300mm) W by 20.9" (530mm) D. Weight: 139 lbs (63kg) each. Finishes: Alder or beech veneers, or silver lacquer, with black fabric grilles. Serial numbers of units reviewed: L 100024, R 100024. Price: $10,000/pair. Approximate number of dealers: 350. Manufacturer: Canton Electronik GmbH, 61276 Weilrod/Niederlauken, Germany. Web: www.canton.de. US distributor: Canton USA, 1723 Adams Street NE, Minneapolis, MN 55413. Tel: (612) 706-9250. Fax: (612) 7069253.
mer are formed in one piece from what is specified as aluminum-manganese I wondered if they meant magnesium and uses a powerful neodymium magnet with a vented polepiece to achieve the necessary high sensitivity. The twin 7" midrange units are constructed on diecast polycarbonate chassis and arranged above and below the tweeter. Canton calls this array DAppolito, but this is not strictly true: the crossovers acoustic slopes are described as fourthorder, with 24dB/octave slopes. To the best of my understanding, the benefits regarding vertical dispersion that accrue from Joe DAppolitos array arise when odd-order filter slopes are used. The midrange units also use a neodymium magnet and an aluminum-manganese diaphragm, this time in the shape of a cone but with a dustcap of the same material continuing the profile to result in a dish shape. This smoothly extends the units response an octave above the crossover frequency. The maximum linear excursion of the 4.75" diaphragm is said to be an astonishingly large 0.87", but below a 110dB SPL the excursion doesnt exceed 0.12", which should result in low distortion. The 12" woofer is constructed on a diecast magnesium chassis and features a pulp cone doped with graphite fibers, this terminated with a rubber half-roll surround to give good linearity and high excursion capability. The ABR uses a flat diaphragm, again terminated with a large rubber half-roll surround. Despite a moving mass of only 5oz, the ABR is claimed to have a resonant frequency below 10Hz, to optimize its reflex behavior. The DC in the Karat Reference 2 DCs name refers to Cantons Displacement Control circuitry, which reduces the level of infrasonic signals both to maximize low-frequency dynamic range and to minimize the production of midbass muddiness. The 16-lb crossover is mounted in its own sealed, decoupled subenclosure behind the upper-frequency drivers. It uses hand-wound coils and ICW capacitors. Electrical connection is via two pairs of sturdy binding posts at the base of the rear panel.

Stereophile, January 2003

Equipment Report

John Atkinson
Canton Karat Reference 2 DC loudspeaker

ERIC SWANSON

Canton Karat Reference 2 DC
System & Setup Vinyl was played on my Linn Sondek/Cirkus/Trampolin/Lingo/Ekos /Arkiv LP player sitting on a Sound Organisation table and amplified by a Linn Linto. CDs were played on a Musical Fidelity Nu-Vista 3D CD player and a Mark Levinson No.31.5 CD transport driving a Mark Levinson No.30.6 D/A processor via a Kimber Illuminations Orchid AES/EBU datalink. I also used an Accuphase DP-85 SACD player, a Technics DVD-A10 DVD-Audio player, and a Z-Systems rdp-1 digital equalizer. A Mark Levinson No.380S preamp fed Mark Levinson No.33H monoblocks via balanced Madrigal CZ Gel-1 interconnects. DiMarzio unbalanced interconnects were used for the Musical Fidelity and Technics players. Speaker cables were AudioQuest Gibraltar, AC cables Synergistic Research Designers Reference2 and PS Audio Lab Cable. A PS Audio Power Plant 300 running at 90Hz supplied power to the preamp and digital players. AC power comes from two dedicated 20A circuits, each just 6' from the breaker box. A No.33H was plugged into each. Sound After some experimentation, the Karat Reference 2s were set up in pretty much the positions in my dedicated listening room where the Wilson Sophias had worked so well last July: 30" (left) and 72" (right) from the side walls and 54" from the wall behind them (all distances measured from the woofer dustcaps). The woofers were on the speakers inner sides, the passive radiators facing the sidewalls. The Cantons were not toed in all the way to the 10'-distant listening seat; my ears were level with the 37"-high tweeters.

Measurements

he big Canton was significantly more sensitive than average, at an estimated 92dB(B)/2.83V/m. However, as shown by its plot of impedance magnitude and electrical phase against frequency (fig.1), it actually draws more like 2W from the amplifier to achieve this rating. With a true 1W drive, its sensitivity will be exactly to specification at 89dB/W/m. The impedance stays within tight 3 and 6 ohm limits from 70Hz to 40kHz, meaning that there will be
Stereophile Canton Karat Ref.2 Impedance Mag (ohms) & Phase (deg) vs Freq (Hz) 20.000 18.000 16.000 45.00 14.000 12.000 10.000 8.0000 6.0000 -45.0 4.0000 2.0000 0.100 1k 10k 50k -67.5 -90.0 22.50 0.0 -22.5 90.00 67.50

Fig.1 Canton Karat Reference 2 DC, electrical impedance (solid) and phase (dashed). (2 ohms/vertical div.)
only small modification of its response when used with a tube amplifier having a higher-than-average source impedance. However, the phase angle does become large in the midbass, with a combination of 5 ohms magnitude and 45 phase, implying that the partnering amplifier should have good current delivery. The rise in impedance below 20Hz suggests the presence of large capacitors in series with the woofer which limit excursion when it is unloaded at subsonic frequencies. Two discontinuities are apparent in the fig.1 magnitude trace. The one above the audioband, at 22kHz, is due to the ubiquitous metal-dome tweeter resonance and will be benign. However, the one between 100 and 200Hz suggests the presence of one or more vibrational resonances in the 2 DCs enclosure. Fig.2, a cumulative spectral-decay plot calculated from the output of a simple PVDF acceler-
ometer fastened to the back panel level with the woofer and ABR, indicates two quite-well-defined resonances the higher-frequency mode could be detected on all surfaces. All things being equal, I would have thought these low enough in level not to mess with the speakers sound quality. But I could hear them with the Test CD 3 warble tones, and I suspect they added to the extra warmth heard in Joni Mitchells voice and in the double bass. The saddle at 35Hz in the fig.1 impedance magnitude trace suggests that this is the tuning frequency of the big ABR. However, the minimummotion point in the woofers nearfield output (fig.3, blue trace) lies a little lower than this, at 30Hz, while the ABRs output (green trace) peaks a little higher in frequency, at 40Hz. Note that both the woofer and ABR roll out below resonance with twice the usual reflex slope 24dB/octave rather than 12dB/octave due to Cantons Displacement Control technology. This results in a very steep

0 Amplitude in dB

-40 10

100 Frequency in Hz

Fig.2 Canton Karat Reference 2 DC, cumulative spectral-decay plot calculated from the output of an accelerometer fastened to the cabinets back panel above terminals. (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz.)
Fig.3 Canton Karat Reference 2 DC, nearfield midrange (red trace), woofer (blue), and ABR (green) responses plotted below 1kHz, 1kHz, and 800Hz, respectively, with their complex sum (black) plotted below 1kHz.

Since I picked up our April 2000 Recording of the Month, Joni Mitchells Both Sides Now, first on CD (Reprise 47620-2), then on the Bob Ludwigmastered DVD-A (47620-9), Ive been listening to a lot of the Canadian singer. Recorded at Air Lyndhurst in North London, Both Sides Now presents Mitchell working through a collection of standards in lushly orchestrated arrangements that sounded suitably rich via the Cantons. Her sexy, smoky voice the huskiness indeed courtesy of her years of smoking sounded a little smokier than
I remembered from the Mission Pilastros I reviewed last month, but the Karat Reference 2 DCs shared with that English speaker the ability to hold separate and keep distinguishable low-level instruments in the mix, even when others are playing loudly. For Joni Mitchell to explore the jazz vocal repertoire so successfully should come as no surprise to anyone who appreciated her reading of Summertime on Herbie Hancocks 1998 George Gershwin tribute (Verve 707-2). Again, her voice on this cut sounded
smoky through the Karat References, but it also sounded superbly articulate, as did Stevie Wonders harmonica solo. The Cantons reproduced Ira Colemans double bass not only with plenty of weight, but also with an excellent uniformity, notes neither jumping forward nor sounding recessed. Of course, Joni Mitchell was also taking her listeners into improvisational voyages almost a quarter century ago, on Mingus, her tribute to Charles Mingus (Asylum K53091, LP), which in turn reminded me that it had been too long
rolloff for the combined output of the units (black trace). The crossover between the woofer (blue) and midrange units (red) appears to lie at 150Hz, as specified, but with asymmetrical filter slopes. The midranges roll off at 24dB/octave below 100Hz, the woofer at 12dB/octave above the same frequency. Fig.4 splices the black low-frequency trace from fig.3 to the Karat Reference 2 DCs farfield response, averaged across a 30 horizontal window on the tweeter axis. There is a notable absence of peaks and dips in the response. While the upper bass is humped up by 5dB or so, this will be due at least in part to the fact that this is a nearfield measurement, which assumes a 2pi (hemispherical) environment. The tweeter seems to be balanced a couple of dB hot, but as the top octaves only occasionally sounded lifted up, I suspect that the listener identifies the relative lack of energy through the upper midrange as politeness rather than the treble as being excessive.

The Cantons midrange units get a little directional at the top of their passband (fig.5), but the corresponding flare at the bottom of the tweeters passband doesnt extend as high in frequency as is usually seen, the driver also starting to get directional above
5kHz. All things being equal, this might tend to work against the onaxis energy excess in rooms with typically absorptive furnishing. The radiation pattern in the vertical plane (fig.6) reveals that the listeners ears need to be at a level between the cen-
Fig.5 Canton Karat Reference 2 DC, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 905 off-axis, reference response, differences in response 590 off-axis.

1000 Frequency in Hz

Fig.4 Canton Karat Reference 2 DC, anechoic response on tweeter axis at 50", averaged across 30 horizontal window and corrected for microphone response, with the complex sum of the nearfield responses plotted below 300Hz.
Fig.6 Canton Karat Reference 2 DC, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 205 above axis, reference response, differences in response 510 below axis.
since Id played 1980s Shadows and Light (Asylum HDCD 704-2). What a band she put together for this set: Michael Brecker on tenor sax, Pat Metheny on guitar, Lyle Mays on keyboards, Don Alias on drums and percussion, and the incomparable Jaco Pastorius on fretless Fender Jazz Bass. Goodbye Pork Pie Hat is included, of course, but what a joy the jamming is on The Dry Cleaner from Des Moines. Joni scats and spirals the vocal line over initially brushed drums and a walking bebop bass line in which Jaco uses every technique in his immense arsenal to explore the songs changes. Toward the end of Breckers Coltraneish solo, with Alias switching to sticks, Jaco boogies up the B-flat scale in 10ths, adding so much to the tension that, after a couple of choruses and a brief coda, there is nowhere for the music to go other than to stop. Which it does. This was musical magic. The Karats effortless dynamics both macro and micro superb clarity, and generous but well-defined presentation of the kick drum and Jacos bass all helped raise the musics emotional temperature, and allowed me to join in the involvement shared by the musicians. However, this track did reveal a touch of excess treble energy in the Cantons balance, the tenor sax and snare drum sounding a little too fierce and cymbals a bit too hissy. Jaco also appeared on Mitchells Don Juans Restless Daughter (Asylum HDCD 701-2), his awesomely detuned C (32Hz) announcing the transition from the Overture to Cotton Avenue. The Cantons reproduced Jacos bass in full measure, with the evenness of tone I noted above. But again, Jonis voice occasionally sounded a bit thinned on top, with slightly more lower-midrange formant apparent than Im used to. Of course, these are old recordings, and its perhaps unfair to demand that a speaker cover up what might well have been a slightly heavy hand on the treble EQ. And the Karats high frequencies were superbly free from grain. Despite my feeling that the top two octaves were balanced somewhat on the generous side as I said, cymbals could sound slightly too hissy, with less of a burnished sheen than is ideal violins did not sound wiry. With recordings that had been made with audiophile sensitivities in mind, the Karats lack of high-frequency grain allowed instrumental tonal qualities to come over in an extremely convincing manner. Yuri Naumovs nine-string guitar on Sneaky Blues, from his selfrecorded Guitar Stories CD (2001, YN03, available from www.russian blues.com), was recorded with the very neutral-sounding Earthworks microphones and sounded about as uncolored through the Cantons as I have experienced. (Well, no, I have not heard any other nine-string guitars, but there are commonalities shared by all acoustic guitars.) Of the Cantons midrange I have nothing to say, other than to note that it shares the trebles effortless clarity without being disturbed by discontinuities

ters of the two midrange units 33"41" if the low treble is not to sound recessed. This vertical-plane behavior contributes to the in-room balance (fig.7), meaning that it pretty much corresponds to the on-axis response, with the low treble somewhat lower in level than the upper octaves. In the time domain, the step response (fig.8) indicates that the tweeter and midrange units are connected in inverted acoustic polarity, while the woofer is connected in positive polarity. Because of the speakers mass, I couldnt lift it off the ground for the measurements, which means that an early reflection from the floor can be seen at the far right of this graph. I windowed this reflection out before performing any FFT-derived responses, and also to generate the farfield cumulative spectral-decay plot (fig.9). This is overall quite smooth and clean, though a very slight amount of delayed energy can be seen at 5.5kHz, the frequency of a small step in the on-axis response. These measurements indicate a well-engineered design that, while not being completely neutral, will offer excellent sound in all but small, John Atkinson lively rooms.
Fig.7 Canton Karat Reference 2 DC, spatially averaged, 13-octave, freefield response in JAs listening room.
1.5 1.0 0.5 Data in Volts 0.0 -0.5 -1.0 -1.5 -2.Time in ms 6 7
Fig.8 Canton Karat Reference 2 DC, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).
Fig.9 Canton Karat Reference 2 DC, cumulative spectral-decay plot at 50" (0.15ms risetime).
and colorations. It could sound a little polite, however. The low frequencies were extended and powerful, the warble tones on Stereophiles Test CD 3 being reproduced in full measure down to 32Hz. Useful energy was still apparent at 25Hz, but there was nothing to be heard at 20Hz. The 2 DC did not boom, but there was plenty of energy present in the upper bass musics power region. When there were low frequencies present as in the excerpt from Elgars Dream of Gerontius on Test CD 3, where the bass pedals of Ely Cathedrals organ are used to underpin and reinforce the harmonies at the grand climax it spoke with authority. The Karat References produced a big sweep of sound on well-recorded orchestral recordings. Our Recording of the Month for June 1998, Elgars Enigma Variations and In the South over-
ture with the Bournemouth Symphony under George Hurst (Naxos 8.553564), was reproduced with the appropriate majesty and with a clear window into the inner voices, the latter so important to Elgars scoring. And when the melodies are restated by the brass, the Cantons accurately reproduced the blatty brassiness of the trombones, as Stereophile founder J. Gordon Holt refers to the instruments characteristically spiky and asymmetrical waveform, which needs both treble bite and plentiful energy in the lower midrange to sound correct. However, the bass drum and double bass in the Elgar did tend to woof a little more than they did with the similarly priced Wilson Sophia, which actually put out more low-frequency energy. This appeared to be associated with narrowband cabinet resonances

between 150Hz and 200Hz. Conclusion When I asked what a pair of the wellengineered Canton Karat Reference 2 DC costs, I expected to hear considerably more than $10,000. The Cantons smooth but somewhat trebleforward balance will work better in larger, well-damped rooms than in small, sparsely furnished spaces. The speaker will also benefit from being used with high-quality source components and electronics. When those conditions are met, the result should be very satisfying music. With its powerful-sounding low frequencies, clean and grain-free highs, coloration-free midrange, high sensitivity and dynamic range, and stable, precise stereo imaging, the Karat Reference 2 DC easily justifies its flagship position in s Cantons range.
Posted with permission from the January 2003 issue of Stereophile Copyright 2003, PRIMEDIA Inc. All rights reserved.
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pure design

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Karat Series

Reduction to the essentials: The Karat series from Canton combines pure design with pure listening pleasure. State-of-the-art technology in simple yet elegant furniture quality cabinets represents the Canton ideal of loudspeakers. Information about the Karat series as well as the complete line of Canton loudspeakers is available in our new Living HiFi Magazine. To receive a free copy, please contact Canton, 1723 Adams Street NE, Minneapolis, MN 55413, call 612-706-9250, or visit www.cantonusa.com.