Description: Three-way, reflex-loaded, floorstanding loudspeaker. Drive-units: two 1.1" (28mm) soft-dome tweeters, two 6" (150mm) Magnesium Silicate Polymer (MSP) cone midrange units, two 8" (200mm) MSP-cone woofers. Crossover frequencies: 730Hz, 2kHz (8kHz from two to one tweeters). Crossover slopes: 6dB/octave, first-order. Frequency response: 27Hz-25kHz ±2dB. Sensitivity: 90dB/2.83V/m. Nominal impedance: 4 ohms, 3.3 ohms minimum. Impedance phase shift: -57 degrees to +21 degrees (20-200Hz), -4 degrees to +24 degrees (200Hz-20kHz). Long-term power handling (…
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Sidebar 2: Review System
Analog source: Linn Sondek LP12/Cirkus/Trampolin/Lingo/Ekos/Arkiv LP player on a Sound Organisation table.
Digital sources: Mark Levinson No.31.5 CD transport; Mark Levinson No.30.6 D/A processor; dCS 972 upsampler; Technics DVD-A10 DVD-Audio player; Musical Fidelity Nu-Vista 3D and Ayre CX-7 CD players.
Preamplification: Linn Linto phono preamp, Mark Levinson No.380S line preamp, Z-Systems rdp-1 digital control center (updated to handle 96kHz sources).
Power amplifiers: Mark Levinson No.33H monoblocks.
Cables: Datalinks: Kimber Illuminations Orchid…
Sidebar 3: Measurements
The Dynaudio C4's voltage sensitivity was to specification, at 90dB(B)/2.83V/m. However, as the speaker's impedance magnitude (fig.1, solid trace) drops significantly below 8 ohms for three octaves in the lower-frequency range, where music has a considerable proportion of its energy, it is fair, I feel, to consider it as a 4 ohm load. The electrical phase angle (fig.1, dashed trace) is generally benign above the lower midrange, but the combination of -46 degrees and 5.1 ohms at 73Hz will rule out the use of amplifiers that are not happy with low impedances.
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Wes Phillips wrote about the Confidence C4 in March 2007 (Vol.30 No.3):
At 69" (1770mm) high by 10" (255mm) wide by 17.5" (450mm) deep, the $18,000/pair Dynaudio Confidence C4 definitely falls into that category of loudspeaker known as "freaking large." So I was startled when, after I'd had to replace them for a short period with speakers half their size, my wife referred to the C4s as "not so big."
"But these are smaller."
"Yes, but they actually occupy a larger footprint," she observed. "And the Dynaudios are so slender, they seem to disappear into the room. Besides, the…
Sidebar 4: WP's Associated Equipment
Digital Source: Ayre C-5xe universal player, Slim Devices Transporter WiFi D/A processor.
Preamplifiers: Ayre K-1xe, Krell Evolution 202.
Power Amplifiers: Ayre MX-R, Krell Evolution 600, Portal Paladin (all monoblocks).
Cables: Digital: Stereovox XV2. Interconnect: Krell CAST, Shunyata Research Aries. Speaker: Shunyata Research Lyra, Stereovox Firebird. AC: Shunyata Research Anaconda & Orion.
Accessories: Audience adeptResponse power conditioner; Ayre L5 AC line filter; Furutech eTP60, Shunyata Research Hydra power distributors; FP20A…
Sidebar 5: 2007 Measurements
The loudspeaker Wes Phillips reviewed before the Dynaudio C4 was the similarly sized but almost twice-as-expensive Canton Vento Reference 1 DC (Stereophile, November 2006). As I had published a complete set of measurements of the Confidence C4 with my original review, I thought that, to accompany Wes's Follow-Up, I would measure its response in his listening room, using the same spatial averaging technique I have used for the past 20 years. (I take nine spectra across a rectangular window centered on the listening position; the average, weighted slightly…
Wouldn't you just know it. As soon as I decide on a formal regime of measurements to accompany Stereophile's loudspeaker reviews—see Vol.12 No.10, October 1989, p.166—along comes some hot new technology that changes everything. Robert Harley reported in last month's "Industry Update" column how impressed he and I were with the new MLSSA measurement system from DRA Laboratories.
We were sufficiently impressed that we persuaded Stereophile's publisher Larry Archibald to splash out and buy one.
MLSSA is an expanded acronym for MLS or "Maximum Length Sequence." The system's…
Lars recently received a device that looks and works like a $25 digital alarm clock and is said to subtly improve the overall sound of one's system. It's the ElectroTec EP-C, from a company called Coherence Industries.
You plug it in and it's supposed to improve the conductivity of your household electrical system—have a "smoothing effect" on the motion of electrons so there is less chaos...less anarchy! More to come as I try to digest all of this. (As you can see, I'm getting into what seems to be Auntie Enid Lumley or Peter W. Belt territory, and over my head. Possibly out of my mind…
Thomas J. Norton commented on the Coherence Clock in October 1990 (Vol.13 No.10):
Time Out—Consumer Alert! Back in the May 1990 issue, Sam Tellig told of a $495 device called the ElectroTec EP-C from Coherence Industries. The EP-C precisely resembles a $25 Micronta alarm clock available at your corner Radio Shack. Employing this "clock" was claimed—by Coherence—to improve the sound of one's system—although it is only plugged into the wall, not directly connected to the system in any fashion (except by its sharing of the house wiring). Sam did note some improvement, although he was not…
Sam Tellig commented on the Coherence & Tice Clocks in January 1991, Vol.14 No.1:
Just when I thought it was safe to open the mail, someone else sends me a tweak. This time, it's TDK. That's right, the tape people—the last company from whom you might expect to receive an audiophile tweak. The world is no longer safe for Len Feldman, Hans Fantel, and Julian Hirsch!
The product is TDK Digital Noise Absorbers and should be in stores by the time you read this—$10/pair. If the product were distributed by one of the wire bandits, perhaps a pair might cost you three to five times as…