Coincident Digital Master Speaker
Audio - Feb 97
by Len Schneider
Old MacDonald's audio farm has produced some strange harvests lately; witness the recent bumper crop of single-ended triode amplifiers. Unfortunately, this retro-mutation has caused a small-scale musical famine, as most speakers just murmur when tickled with the low-power output delivered by many of these watt-not designs. But, given their popularity among some avant-garde practitioners of the audio art, it was inevitable that designers would soon offer speakers with the high-efficiency and benign impedance curves demanded by these little glowing gremlins.
A case in point is Coincident Speaker Technology's Digital Master, a smallish two-way, stand-mounted loudspeaker with some interesting qualities. Available in a variety of veneers in addition to its standard black-lacquer finish, the Digital Master measures 18 inches tall x 11 inches wide x 16 inches deep. Lest you think "box," be advised that this enclosure has no parallel surfaces and looks, uh, different. It has an 11 x 16 inch footprint and narrows to 8 x 11 inches at the summit. But you can't even rest a wine glass on it because the top surface slopes down to meet a backwards-canted, fully finished front baffle that's beveled to help minimize diffraction. Coincident calls the design AWE (Asymmetrical Wall Enclosure) and claims that it, along with the absence of internal bracing and damping materials, eliminates internal standing waves and sonically destructive reflections.
This version of the AWE enclosure also eliminates any grille covering, revealing the drivers in all their unprotected splendor. Although this helps improve high-frequency dispersion, Coincident recognizes that some people may not like the look and thus provides foam covers that attach with Velcro.
The Digital Master's drivers, though relatively conventional, are carefully matched. For the ferrofluid-damped silk-dome tweeter, Coincident claims a 30-kHz upper limit. Bass/midrange is left to an 8-inch polypropylene woofer driven by a 2-inch voice coil situated in the gap of a large, 5½-pound magnet structure. The basket is magnesium casting, and the surround has been optimized for use in the vented enclosure.
The speaker's crossover is a first-order (6-db/octave) Butterworth alignment at 2 kHz and consists of just two components, a polypropylene cap in series with the tweeter and an inductor on the woofer leg.
A single set of gold-plated binding posts, thankfully unrecessed, makes amplifier connections easy, The crossover design doesn't support bi-wiring, so there are no additional terminals or jumpers to juggle. The only other rear-panel element is the reflex port.
Finish, if the mahogany samples auditioned are any indication, is good and should withstand casual cleanings. Although I had to remove residue from adhesive tape securing protective Styrofoam rings around the tweeters (a somewhat crude packing technique for speakers selling for $1995 per pair!), the enclosures were not affected by the recommended solvent.
Coincident suggests a 50-hour break-in period for the Digital Masters before attempting serious listening. I complied, placing the speakers face-to-face and driving them out of phase with a continuously repeating complex phase sweep tone from a "system burn-in" track.
As I began to play music, I experimented with room placement and did not find any unexpected anomalies. The Digital Masters were quite happy in the same spots where I've placed many small dynamic speakers over the last few months. They ended up about 3½ to 4 feet from the back wall and five feet apart, with the midpoint between the two offset toward the right of the room. One hint: Don't place the Digital Master (or any other stand-mounted speaker, for that matter) so that the woofer's center point is the same as that from the floor to the woofer. If you do, you'll probably reinforce room standing waves to the detriment of lower-midrange clarity. Toe-in, at least in my room, didn't much change tonal balance or imaging, so I aimed the speakers straight ahead. I suspect that the tweeter's relatively even dispersion and the beveled baffle's shape contributed here.
I'm not convinced that single-ended triode amps offer the sonic salvation claimed by their advocated, so I disregarded Coincident's repeated references to the synergy resulting from using such an amp with its speakers. Instead, I used two solid-state amps: a pair of Rotel RMB-100 MOS-FET monoblocks and a slightly older Adcom GFA-555II bipolar behemoth. Neither the Rotels nor the Adcom caused any hemorrhaging (internal or external) of the Digital Masters, despite my rather cavalier approach to volume control.
The Digital Master's high sensitivity (rated at 91 dB) proved a real benefit. Even at high volume, I had no sense of the system strain that often clouds less well-matched combinations. Because the Adcom's brute power, a requirement with many gourmand-appetite speakers, was totally unnecessary, I quickly went to the less-etched sounding Rotel amps for the balance of my listening sessions.
If there's any one track that reveals dynamic compromises, it's the (in)famous "Tricycle" from the Flim & The BB's album of the same name. About a year or so ago dmp's Tom Jung remastered the original 1982 recording and released a limited-edition disc (dmp Gold-9000) that is significantly better in many ways than the original. The Digital Master speakers rendered the initial drum and synthesizer shots with impressive delineation and body. High frequencies, particularly he nicely syncopated stick work on hi-hat cymbals, were also well presented. Further on, the speakers did justice to Flim Johnson's Alembic bass as he ran through some upper-fret gymnastics (listen particularly to the segment beginning at 1:17). On the downside, I did miss the bottom octave. Track 1 has significant content below 60 Hz that the Digital Master did not render clearly. To its credit, however, the speaker did not appear to shroud this lack with an artificial mid-bass peak, (Cellos, for example, were reproduced with natural timbre.) For those who say that small speakers can't be expected to descend to the musical basement, I can only point to a few (Platinum's Solo, for one) that will go significantly lower than the Digital Master, but they demand far more powerful amplifiers. In the world of speakers, there's no free lunch!
Further listening, this time to Stravinsky's The Rite of Spring (Reference Recordings RR-70CD), brought other elements into clearer focus. The Digital Masters convincingly conveyed the brassy, urgent stridency of "The Sacrifice". While maintaining orchestral coherency, these Coincident speakers unraveled the complex interplay between violins and brass very well. If there was a question, it centered around the Digital Masters' ability to recover from each of the successive tympani strikes beginning at 7:14. To my ears, low-frequency bloom was a bit restricted.
An old favorite, The Eagles' "Hotel California" (from Hell Freezes Over, Geffen GEFD-24725), revealed a minor midrange anomaly: The audience recognition (primarily handclapping), which begins at 1:20, sounded slightly more hollow than with some other speakers. Although that was a difficult test, I was somewhat surprised to note how quickly that became apparent.
Imaging was acceptable if not spectacular. Lateral spread was very good. The Digital Master anchored things so well that side-to-side movement produced only moderate shifts in the aural canvas. Depth was slightly less impressive, as the speaker tended to foreshorten the rear soundstage. This was not a major failing, however, as "Witchi-Tai-To" (on Oregon's Beyond Words, Chesky JD 130) placed Paul McCandless' penny whistle and soprano sax slightly outboard and far enough behind the right speaker so that they did not "crowd" other instruments. And within its lower frequency limits, the Digital Master projected Glen Moore's upright bass in a dynamically convincing and coherent manner on the same track.
I found the Digital Master a dynamically pleasing loudspeaker. Its ability to present small level differences accurately, without destroying musical integrity, makes it a member of an exclusive club. Its overall character is essentially neutral though the critical midrange, although it did appear to have a somewhat reticent quality about the frequencies immediately above-fret noise on acoustic guitar, for example, was a bit subdued. High frequencies were very extended and exhibited only a trace of stridency when hit with high-level transients, such as brass fanfares.
Although you might want some augmentation for extended low-frequency reproduction, matching this speaker to an ordinary subwoofer may be difficult, as it is clean and reasonably articulate to about 60 Hz. But the Digital Master is relatively easy to position in a room, and its driver complement and shape combine for imaging that will let you focus on individual threads in a complex aural tapestry. That ability, along with a penchant for making the most of whatever amplifier power is available, placed the Coincident Digital Master in a rather elite category. You owe yourself a careful listen.